so, after breaking the rod in the 4 valve head motor back in may, been gathering parts and getting other projects wrapped up to repair it. of course.... im me so here we go. watch this space. going to go 250 2 stroke. Pipe showed up yesterday, and the schedule in the garage is clearing so this should ramp up quickly.
Complete rebuilt LT250R motor also arrrived, will start documenting when i get it back home from where im storing the bike (work)
Counterbalanced LT motor is a great choice for a little bike and should really help with the vibes 👍
Stoked to watch this progress.
Great choice of engine. They got really good in '87.
:popcorn2:
thanks. it's actually an 86 but I got a killer deal on it . still 400% more hp than a stock grom. :taz:
Quote from: m in sc on September 04, 2019, 12:20:02 PM
thanks. it's actually an 86 but I got a killer deal on it . still 400% more hp than a stock grom. :taz:
Absolutely! It'll be waaay more fun.
Hell yea I love a good engine swap!! :righteous:
it should be fairly straightforward i think, compared to the other stuff ive done. theres plenty of room from what i can tell. the pipe routing and a few small electrical unknowns are really the only things i really dont know about yet.
Hey M, why not go for a more, ehhem, interesting motor such as a motocross 250?
motocross motors are a pain in the ass on a streetbike, trust me on that. 36 hp will be quite plenty. with 27hp i could hit 95 so.... rideability is a factor here.
As is staying alive, I would think. :whistle:
I always love a good frankenbuild. Standing by... :popcorn2:
:metal: :metal: :metal:
preliminary eyeballing seems to show that this should be pretty good to fit. to that point.. i think the rear motor mount may actually line up by absolute coincidence. or be extremely close. I still need to add an upper/front, remove the stock upper mount on the grom frame, and figure out how to clock the carb out a bit.
I also just sort of set the fmf pipe i have for the 250 motor in there, i should be able to run it with minimal mods, some re-clocking and the stinger will need to be reworked. (it should sit back about 4-6" from where it is in there now) when i get the original motor out in the next day or 2 this will make things a lot clearer. :haw:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/20190911_183229-e1568301837811.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/20190911_181903.jpg)
What a great build idea. How will you keep the front tire on the ground?
eat more donuts. :cheerleader:
(http://www.2strokeworld.net/wp-content/uploads/LC-HYBRID/GENERAL-PICS/donut-torque.jpg)
(https://i.imgflip.com/3al20r.jpg)
This should be another cool build! :popcorn2:
been busy all weekend on other stuff, but got some rear plate templates made. looks like i need to shift motor to RH side about 3/8 of an inch but... its hanging in there. the measuring part. not exciting but pays off in the longrun. and yes, this will be a bolt in as much as i can so i can replace motor or frame down the road if need be.
:metal:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/20190914_210220.jpg)
so, back to the electronics. :wave:
i found they make new aftermarket -stock configuration- stators for these motors, claims 130 watts output. (and dirt cheap) since im running led headlights and such, and im sure that 130 w is ac, i can, as ben suggested, unground the windings and go full wave. the new units are like 40 bucks, so worth it. the real kicker is, i probably -could- use the whole stock harness and ecm on the bike as the motor input is only the 4 wires from the stator. 2 ac charging leads, 1 trigger and 1 for the coil. :dawg:
the stock lt250r setup is the same output. the neat thing about it is the rev-counter would still work on the stock dash, and would save me from a boatload of wiring. the downside is i would have to get the ecm reflashed to 1: disable the cel and 2: out a 2 stroke timing curve in it. lots to consider.
currently drawing up the engine plates to have them laser cut out of aluminum :science:
Sweet!
so as an update, got the rear mounts done, did them out of 1/4" steel plate, this put the sprocket offset right where it needed to be.
this moved the motor forward "0.600 and up almost an inch for chain alignment. this of course tightened up things for the intake a bit (more on that below)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/rh-plate1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/rhplate2.jpg)
if you look at the main bolt, you may recognizer it as an R5 front axle, it is, cut down with a shoulder welded on the cut side (as i need a 15mm bolt). I had a few of these with crash damage laying around, so in it went.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/rhplate1.jpg)
now that that was set, i needed to make sure the motor was set so i can get some form of an intake on there. balancing between the exhaust clearance issues that will crop up (by moving motor any further forward) and screwing up the chain alignment (which was good here now) but dropping it any further, i had to make a concession. even moving the motor up to 2" in any direction, i would have had to go this way, si i just tightened up the clearance and made the intake. the downside is it adds a bend and 2.5" of runner length. :bang: Ive read various theories on this, and hopefully it will just move the power band down some. either way, i'll have to live with it. If i lose a hp or 3 im ok with that. the upside is that the carb will be very easy to get to.
i mocked up up with a aVM35 as the flatslide for the motor isn't here yet. the exhaust is going up and over the other side of the motor.
Not ideal, but should be ok for a 220 lb bike.
clearance to the frame rail. the ID of the runner is 34mm, transitions are smoothed out and no steps.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom250intake-prelim_5.jpg)
^ the bend is a section out of a car header from a turbo'd civic. just had it laying around. the round flange is stainless tube i had lathed down, and th eend plate is just 1/4" plate i hand cut. I am going to face that on the mill as the welding warped it a bot. all filler rod used was stainless.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom250intake-prelim_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom250intake-prelim_2.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom250intake-prelim_4.jpg)
now that all that is set, i can do the fron hung mount for the motor. then, aside from the pipe, all major fab is done. (aside from cleanup, etc)
slight update, but exciting to me, found a guy that can reprogram the stock honda ecm to have a proper 2 stroke timing curve (which i will send him), and set the revlimit to 10-10,5k. also disable the check engine light. this means i can pretty much plug and play the electrical from the suzuki motor after the grom ecm is reflashed, utilising the stock key, kill switch gauges, speedometer, etc. just need to adapt the 2 ac charging wires and the trigger and ignition ac coil wires to the right plug and done. :celebrate:
Good stuff, always nice to be able to use the stock harness. I was able to jump in everything I needed to do my gamma conversion right into the stock Suzuki harness and I'm really glad I did. Same deal, stock key, stock kill switch and power for my tac and powervalve all on tap! Cheers Mark! -Ian
indeed that is awesome. :clap:
, the ignition is a huge deal for me. and the ability to use the stock digital gauges as well. did the same with the rd powered ninja 250 as well, but the cdi/ecu here is definitely a step up from what i thought i could get away with
Most righteous news Yo :metal: :metal:
Gonna be badass- hope to see it at the Gap next Spring!
you're at it again!
:toot: :science:
So cool, just what that bike needs.
This is one heck of an ineresting project! I like that you are explaining all your doing, its making the thread a good read.
thanks. its going slow as I'm gathering parts, waiting on a set of cr125 radiators. and a different pipe as I want to route it under the motor,. I'll have to do a lot of work to get that the way I want it but should pay off
mockup using aftermarket cr radiators. theres some tweaking and trimming that needs to be done. primarily the filler neck needs to be relocated to the far left and the permanent mount sneed to be put in. reclock the crossover tubes as well. when i trim back the black cowling it should clear. Ironically, the (up to now fake) vents in the sidecover will now actually be functional to let the heat out, and i will need to trim the stock front black cowlings as well to surround the radiator top tanks better.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom-rad-mockup_2.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom-rad-mockup_4.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom-rad-mockup_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/grom-rad-mockup_3.jpg)
the other exhaust pipe should be here tomorrow. thats the last time consuming fabrication thing to figure out. :devil:
exhaust layout. went with stock chamber, the fmf i had just wasnt going to work out.
tacked up. welds will be cleaned up, tabs added and removed, etc. as a side note, stock pegs going back on, will clear kickstarter beautifully with them.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/pipe-layout_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/pipe-layout_2.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/pipe-layout_3.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/pipe-layout_4.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/pipe-layout_5.jpg)
Righteous :metal: :metal:
That pipe is going to give it some serious low end.
SOME DETAIL UPDATES:
So, the radiators finally got permanently mounted (see below) with welded on mounts on the frame. But the filler neck was dead in the way of the fork at full steering lock. I didn't want to reduce that, so i needed to move the filler, and clock it around 90 degrees to get the overflow pointed back. also, the upper crossover was facing the wrong way, and the lower pipes which go over the intake at the cylinder needed to be canted 'up' a bit. So, sunday was aluminum welding day. after all this was done, i could finally place the bodywork and mod to fit.
mounted but not yet modified.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_11.jpg)
modifying the radiators:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_13.jpg)
facing filler in lathe for welding prep
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_21.jpg)
when i welded this on, was aware of the impurities int he metal, so cleaned and i rewelded some, filling the flaws.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_14.jpg)
david wanted to weld the neck, he has 35 years experience so i was like 'have at it'. i was addressing the final welding on the exhaust pipe and body work while he was doing this.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_26.jpg)
you can see it moved here. note the bodywork on on the RH side, the front cowling modified to fit around the top of the tank.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_17.jpg)
need to clean it up a bit, but you get the idea. also now the upper crossover is aimed back to connect behind the neck to the other tank.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_15.jpg)
LH side done.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_18.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_19.jpg)
i will be painting the radiators black after i pressure test them.
this is the final fitment. this needed to be done to dictate where cable ran, plumbing, coil mounting, electrical routing, etc. Had to cut the lower black trim as well, but the painted bodywork fits with one slight mod per side. this was my goal from the get go.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_16.jpg)
pipe is fully welded, need to add mounts, and address rear brake lever after that (next).
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grompipe-radiators-10-20-19_27.jpg)
sorry for the boring details but this was basically a full day of finalizing work on this part of the project. :cheerleader:
Getting closer... :taz: :taz:
Nicely done Mark ! Looks great. :clap:
Oh yeah...love it Mark!
Chuck
few updates:
moved LH subframe support to clear uni filter (yes i'll get a new filter). will clean up all this when i take the motor out to do final build.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/intake-related/carb-relocate-intake_5.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/intake-related/carb-relocate-intake_2.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/intake-related/carb-relocate-intake_6.jpg)
all fits within body work. :haw:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/intake-related/carb-relocate-intake_3.jpg)
finalising exhaust. going to move the muffler up about 2" closer tot he body work, this was just preiminary. need to cut stock mounts off muffler housing too.
Getting there.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/exhaust-muffler-mockup.jpg)
also ordered a zeel box from economy to handle the ignition curve
Guess I have to dig out my F9 motor....... :dawg:
ok...?
0h man, this thing is going to rip with that Flatslide carb and a zeel electronic controller. BRAPPPPPPP!!!!! :eek:
Quote from: m in sc on October 30, 2019, 12:16:42 PM
ok...?
Kidding, the F9 350 motor would be dragging the ground in the G3ss frame.............. :dawg:
yeah, you'd need a -slight- chassis upgrade :dawg:
got the muffler location sorted. down to cosmetics and finishing a few of the welds.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/250grommuffler-4.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/250grommuffler-1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/chamber/250grommuffler-3.jpg)
8)
Sweet :celebrate:
Gonna be one bad ass Grom! :whoop:
That's going to turn some heads. It's going to need one of your no cam no valve stickers. :clap:
Quote from: Organicjedi on November 03, 2019, 10:49:34 PM
It's going to need one of your no cam no valve stickers. :clap:
heh, was just looking at the nunja build pics the other day. man, my welding was shit on that in some spots. :dawg: strong but UGLY. :eek:
I might have to get some made up, in 'Honda' font. Also, apparently its been dubbed the 'gromzuki'
As a slight update,t he exhaust is completed, done, painted. so, on to the lower engine torque mount, then the actual engine build. :cheerleader:
Bit of an update. All the fab work is complete, and i finally got the lower end together. One thing that annoyed me was the lack of a neutral light. There was a casting recess for it, so i utilized that, and made one out of delrin ont he lathe in the least impactful way i could. Used an M4 bolt, threaded offset into the delrin end that went into the motor, and passed thru the case and outer delrin disc after i drilled the 6mm hole. used case sealant on the hole and both sides to seal it up. Used the stock grom pin and spring from the shift drum as the contact. hole was already in the suzuki drum for it. :devil:
I got the undertray back in, wiring routed, and the check engine light disabled. I will be using the stock harness and aftermarket but 'stock style' ecu (with no rev limiter). to get the timing right, i mounted a zeeltronic box from Economy Cycle. I need to advance the pickup so i can get a baseline to program a curve.
at ti spoint its just a bit of wiring and assembly, all the really hard work is done as far as installation, then i need to pretty up the radiators and mount and plumb them, should be pretty easy.
Kickstart is modded and clears pegs as well.
Nice thing is, i can tilt the motor 'forward' to work on if i just use the back mount to hold it. the lower and front mounts are removable. , the lower can actually just pivot down.
few pics. after i did all this, i took trans back out cleaned it all out with brake clean, blew out with air and reassembled.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_3.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_4.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_6.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_7.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/transmission-n-switch_8.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/rewiring-undertail_3.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/rewiring-undertail_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/rewiring-undertail_4.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/lowerend-in-frame_3.jpg)
clunky vid of n light working.
http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/motor-install/testing-n-switch.mp4
Sweet :celebrate:
Have you checked out the small bore event at Barber? This would turn some heads there
Quote from: Clem on November 20, 2019, 07:14:10 PM
Have you checked out the small bore event at Barber? This would turn some heads there
My buds from Scooter Swapshop head out there every year. Tons of insane 2Ts. 👍
Ive heard of it, prob be fun w that and the g3.
Pretty much sorted out on the wiring front.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_6.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_2.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_5.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_7.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_8.jpg)
Sweet!
Lookin good!
Is that rust (looking) spinny weighty looking thing above the rotor the counterbalance?
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/WIRING/GROM250-FINAL-ENGINE-WIRING_5.jpg)
yes, thats one half of it. the shaft goes through the motor and there's another weight on the other side as well, with a spring cushed gear to the primary drive.
slight update, was in fla the past 4 days came back last night to plan the final assembly of this.... and relaised i left a bearing retainer out of the case. DOH! look slike i'll have to pull it apart one last time. the retainer was in with the balancer parts but is for the main input bearing for the trans. glad i caught it and was looking over the diagram in the repair manual (which is how i realised it wasn't in there) :bang: at least i didn't get it completely together yet.
Somebody else had a similar idea. Looks sweet
The welder at Tyga who made that exhaust is an artist
Cool project!
yeah, im familiar with the yz grom. its cool but the details are.. if you look really close, not my cup of tea. The reason its taking me so long to do mine is the details im doing. serviceability, not cutting the frame, adding a cradle, etc. Not taking away from that one, its very cool. Just not the way i wanted to do mine.
And, it lives. Did a few fire ups but with no cooling system plumbed up, just a short test fire. this was the 2nd one. trans, clutch, and charging system all good. :metal: :haw:
next up: plumbing and tuning. I have to say, the kicstart situation on this sucks.. it clears but its awkward. I'll figure it out.
http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/grom-2ndrun.wmv
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/final-fab-black-radiators_1.jpg)
and, this cost me a day. it was one of those 'whats this part in the box?' (after the motor was assembled :bang:) No, i didnt run it prior to getting this in. luckily i caught it.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/20191127_195914-rotated.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/20191127_200240-rotated.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/20191127_221108-rotated.jpg)
Sounds good! :blah: :celebrate: :celebrate:
This is super rad!
I love little things!
Such a good job. And, I am glad to hear that there is a cradle. And, not a cut up thing.
There is a little hacking on my Derbi with the YZ motor.
I am wanting to do a cradle for a RZ350 motor I have laying around.
But, I am still pondering what frame to use.
This thing would be a hoot at the Barber!
Keep on trucking and smoking!!!
THANKS. It not really a full cradle , front and rear and lower mounts are all independent and hand made. I just got all the plumbing finished last night, had to make a really compact in-line temp sensor fitting which took a while on the lathe, but it should eb good to go. Hopefully tonight i can fill er up with coolant and get started on tuning and hopefully have NO leaks.
heres some pics from over the weekend:
made a hardline from pump to LH radiator.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grom250-initial-plumbing_1.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grom250-initial-plumbing_3.jpg)
if that proves to be a problem, i'll order up some stainless tuning and tig weld it together, the tight bends were the challenge mostly.
this is where it terminates on the LH lower radiator
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grom250-initial-plumbing_5.jpg)
the upper setup, the head outlet is just below the Y fitting. the temp sensor is (now) off to the right of this pic. (more to follow)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/radiators-exhaust/grom250-initial-plumbing_4.jpg)
I don't have a direct picture, (you can barely see the clamp & hose end in the pic above bottom of the radiator) but hands down the worst part was the lower crossover on the radiators, the clamps were near in possible to get to, have to use a LOOOONG screwdriver to get to them from the back, as it crosses over the intake on the cyl. But, its in there.
Looks really good YO.
another run video with the zeeltronic installed.
took a tip from chuck on float level on the TM and def helped.
https://youtu.be/tOFJVqmuJ_0
:clap: :clap:
Sweet!
Let me know if you need a test pilot.
I wont bore anybody with more pics as of yet, but in fiddling with it yesterday, it seems the longer intake runner likes to run it a bit richer than i anticipated. Im assuming the velocity is just cranked way up across the venturi of the carb. to the point the intake gets ice cold running it, which isn't necessarily a bad thing and not really unexpected. To the point to get it to rev cleanly i needed to lean the needle out quite a bit.
one odd problem i am having however is the cdi seems to 'double trigger' when you really rev it. to the point the zeel was reading at 5k, then just went to 10k on the readout and hit the rev limiter over 5500. so, i set the revlimiter on the zeel to 20k :eek: and now it revs happy. Im not sure exaclty whats going on there. its an oem rotor and original 'style' but new pickup
and only has 1 trigger ramp, and no debris or whatever is ont he outside of the rotor. Im going to swap the trigger and see if its defective, and also add a ferrite choke to the wiring, see if its pickup up some RF from somewhere. the tach is verifying this anomaly as well. But, its getting there. :devil:
Righteous.
sooooo...
testriding this weekend did NOT go as planned. :taz: Im not sure -exaclty- what happend but Im pretty sure i damaged the piston on the last run. I didn't even get a mile out. Im super confused. wasnt lean, timing wasnt too far advanced, etc.
Im pretty sure it was timing related though. the plug looks dark, no aluminum off throw or signs of overheating. timing, according to book, is 'supposed' to be at 6 degrees BTDC (which seems super late to me).
Jetting was on the rich side. But under load it just went super flat. was smoking a lot then just lost power. restarted to turn around and limp home maded it a bit further back and then quit again, this time water temp got hot, fast, real quick.
everything in motor is new. (well, was). upon running in shop, sounded well, cooling system would cycle and work well.
My -theory- is that the timing is too far retarded witht he box i have and it was firing with the exhaust port open, heated the front of the piston. and stuck the ring. why? my compression gauge now is reading only 70 psi kicking over.
I cant say ive ever had one run as well it did on the stand or in the shop. and then fail so gloriously on a test ride. :whatever:
On the upside, everything else seemed to work great.
jetting was 230 main, (for safety). needle middle, 45 pilot 3/4 out thats stock setting on the pilot. 32:1 ratio.
will put head tonight I think see if theres anything I can find.
so, looks like new piston time and some research :bang: on the ignition unless i find a smoking gun somewhere else
I've seen guys stick their motor on track after the engine having run amazing on the stand. Things change when you're under way, load, vibration, etc..
Man that blows! I've been there and its gotta be one of the worst feelings. I hope you get it figured out, I'm sure you will. Heres hoping it's an easy fix Mark. Cheers -Ian
Frustrating when you don't know for sure what happened.
took head off, piston dome is perfect, only got hot at exhaust side, and quick. (the face). im thinking late timing, ive never seena motor go this quickly though. going to need a bore and piston though, the cyl is smeared around the exhaust port. IMHO, the only 2 thing son this motor it could be is timing, or a blocked exhaust, which im 99.99 percent sure it cant be since i took the whole pipe apart and rewelded it. (but ive seen this with a broken baffle on a chamber before). sigh. :toot:
I hate that for you Mark but feel strongly you'll get it sorted.
Damn
Any chance of saving your cylinder bore with muriatic acid? I've only tried it once, but it worked for me.
Wade
maybe, but i also have a spare cylinder, im not worried about it. I can get it rebored, either of them and a new piston for around 200 total.
so in digging in deeper on thought about this, Im pretty sure i have the wrong rotor for the motor. i bought it off ebay, might have been off a different year or model (maybe lt500) reason being is, the trigger and pickup are fixed. the book states that timing at 6k should be 12 degrees. physically, there's NO WAY this can fire that advanced, the trigger is at 6 degrees, maybe, firing static, max advance. Im not sure it its from an RM or 500 or what, but im going to move it (the stator plate) around while im waiting for the spare cyl to get done and program the offset with the zeel and get a more advanced baseline in it. ( the zeel gives a max of 50 degrees)
if you are familiar with a programmable cdi, you need the physical pickup to be at least at max advance position, physically, for it to work right. a curve is nothing more than a programmed delay in an ignition box. :umm: :science:
as an update, i sent the spare cyl off (which was actually on the stock bore when i measured it) to be checked, probably bored 1 over and a new piston for it installed.
so, i still have the old one on the motor and am able to turn the motor over and check timing with a light. i re-positioned the stator plate which involved making new mounting holes in the plate, so there is now a static angle of 18", then i used the zeel programmer to address this, it now allows for a curve that goes beyond 6 degrees BTDC, my initial curve is now
500 = 6 degrees
1200 = 6 degrees (manual spec 6 @ 1000)
2500 = 9 degrees
6000 = 12 degrees (manual spec )
9000 = 10 degrees
12000 = 7 degrees
rev limiter set to 10k.
this should be a good start. I am able to spin the motor up to 1000 rpm with a fixture tool i made to spin the crank over at the flywheel with a drill, so i verified with a timing light. I still for the life of me figure out how this was supposed to achieve 12 degrees when the rotor/trigger was fixed. However, i suspect the rotor was the culprit since i had to bu one of those, and i'm guessing it may not have actually been for that model, and the trigger was in the wrong place. No way to verify that though. :bang:
Shit happens YO. You will get it...
oh i know. just sharing what i found. some insight to dealing with the zeel mostly.
Cool.
That pipe looks like it's machine welded? Outstanding work.
Cheers, 50gary
thanks, its appreciated. Piston should arrive this week. want to get this thing going again. In the meantime been working on some long overdue car stuff. :whistle:
Getting late in the day on your side of the continent; any luck with the Grom, or are you still under a car?
Wade
funny you mention that. I got it back together today, but its raining. This was about an hour and a half? or so ago. test ride tomorrow but it sounds WAY better. timing sitting at 12 degrees at 6k, at 8 at idle.
THIS is what VERY late ignition timing did to the last one. I had to move the plate 17 degrees :eek: to get it to fire at 8 degrees at idle and 12 at 6k. so, im assuming the rotor i bought was 'off' as everything else was original to the motor. (i didnt have the rotor so i ebayed one and burned myself not verifying)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/2nd-piston/1st-piston-fail.jpg)
new and fresh this morning:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/2nd-piston/2nd-piston-and-bore-fresh.jpg)
:patriot:
I've got a motorcycle project (non 2t) that's been fighting me. I feel your pain, makes success that much sweeter.
I can't imagine too many bikes more fun than that.
From awshit to attaboy, that sounds sweet! Hope you get decent weather in the morning for a test ride...you DID bolt a wheelie bar on that little monster, didn't you?
Wade
Sweet :taz: :taz:
It sounds good. I had no idea those motors turned 10 grand
i did get 2 test rides in yesterday. its definitely WAY better, and just the way is revved and rode def proves the timing was the cause. and that's on me.
The power delivery was VERY manageable, more so than I expected. I didnt have a speedometer hooked up yet, i still need to mount a trigger and set it, but in 5th gear it just plows up a hill. The midrange is great. Im guessing on the 2nd ride i was doing somewhere around 75-80 at one point considering how fast i passed a few cars.
I definitely need to tune it some more, and rethink the kickstarter lever as starting it is really awkward, but i can sort all that out.
water temps didn't go over 180 and the plug looked good, so, good progress so far. :toot:
Glad you got it sorted,...We knew you would :clap:
Keep us posted !
:clap: :clap:
Most Excellent!!!
thanks guys.
small update. rain day mods. had to rework the angle on the kicker. its still a bit awkward but not nearly as bad. used the end off an old worn slap out and bent rd kicker to make it easier on my foot as well. was slipping off and wheel was catching on passenger peg mount, was just terrible.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/kickermods/gromkick_1-rotated-e1579031650680.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/kickermods/gromkick_2-rotated-e1579031679111.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/kickermods/gromkick_3.jpg)
Looks like you got sum of the plastics back on too. Really cool one of a kind bike, I thought of this thread as soon as I got online! :nana:
thanks...oh, all the body work is done, has been for a month+. damn thing looks more factory than it did before for the most part, aside from the pipe on the left. (the stock rear-sets make it look deceivingly stock from 10 feet off :devil: )
LOL that is such a riot. We gotta get those Grom designers to see this.... :dawg:
so, an update.
haven't done a whole lot, but I finally found and ordered a stock CDI box for the LT250R. I wanted to get a baseline on the curve.
well, hot damn. all of a sudden, the timing was WAY advanced. so, i moved the stator plate and pickup back to the middle of the stock slots. and, there it was, timing was spot on :celebrate: . the aftermarket unit must have delayed the timing so much it was hanging back almost 17 degrees. which, is crazy, because thats how much i had to move the plate to get it right. . Im a little surprised just a non programmable box could delay it so much. So, my assumption the rotor was incorrect was, well, incorrect.
The downside is there is no aftermarket replacement for the box unless i go HPI full system. So, i'm going to try top grab another spare unit -just- in case. if the weather holds ill try to get soem test rides in this week. I also had to up the jets i had on hand, so i can actually dial it in.
:toot:
and, 1st commute complete. :cheerleader: :toot:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/grom-250-1st-commute-2-4-scaled.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/gromcommute-2-4.jpg)
I added in a remote coolant tank last night, swapped in a speigler front brake line, and just tidied up this and that. Its really good but i need to absolutely need to go down on the rear sprocket.
1st just runs out super quick, and i physically have the largest from sprocket on it i can fit.
coolant temps stayed around 140-150 on way in, might need to drop the main a touch as well, when you let down off the throttle at WOT a hair it picks up speed a bit.. Better to err on the side of rich but i have some legroom i think.
overflow, machined aluminum filter body we make at work, mounted tot he stock lower exhaust mount hole with a parker quick connect . breather tube at top. some rando clamp i had laying around, looks like an exhaust clamp for a 4 stroke.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/grom-rad-overflow_2-rotated-e1580831452722.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/running-early/grom-rad-overflow_3-rotated-e1580831476917.jpg)
Boy, did that ever turn out nice!
You're going to have to sell a hkit!
edited; fixed those dumb fingers
Most Righteous :taz: :taz:
so, i finally swapped out the rear sprockets. went from a 35 rear, to a 32, then went to a 30 (the smallest they offer that i can run). its actually a 250 nighthawk (?) rear sprocket because its a 520 chain. so, the final ratio is the (largest) front sprocket, 14t, and smallest rear, which is 30. thats a 2.14 ratio, which is insane on a bike, usually.
also dropped the main jet one size, which puts it lower than stock on jetting, but my suspicion is the velocity in the intake is so high, its just pulling a lot of fuel. which is ok. I can run it wot and it doesn't run warm and the plug chops look perfect.
The interesting thing is its so smooth, its -almost- boring, but its overall not. weird.
:patriot:
It's a elevated 2 stroke stocker!
Way better than a motocross engine....
Can't wait to see it in person at Deals Gap meet, maybe I'll feed Mark too many beers and steal it for a ride>>> :celebrate:
C
Anytime, Chuck. :clap: :patriot:
Nice Job, I bet it's a great wheelie machine. :vroom:
Quote from: Tuck on February 14, 2020, 04:02:53 PM
Nice Job, I bet it's a great wheelie machine. :vroom:
Thnaks. oddly, not as much as one would think, which is fine by me. i mean, it will but not unless you want it to or you slam it from gear to gear.
I want to ride it too!! :metal: :metal:
small update. fit an in-bar clamp flush water temp gauge from koso.
cleans up the look a bit.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/GENERAL-AFTER-SWAP/20200219_182452.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/GENERAL-AFTER-SWAP/DSCI1460-scaled.jpg)
also, did mileage runs monday, this was pretty typical, mixed riding. 31 mpg.
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/GENERAL-AFTER-SWAP/20200217_191020-scaled-e1582202280941.jpg)
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/GENERAL-AFTER-SWAP/20200217_191111-scaled-e1582202334362.jpg)
now, just need to mod the spare tank i have for more capacity, and the weather to be better.
Next, you can slap a sidecar on there :dawg:
https://www.ebay.com/itm/2014-2019-Honda-Grom-Motorcycle-GUS-Utility-Sidecar/183964009662
nooooooo :dawg:
I did a good long ride on it yesterday. zero issues for about 2 hours mixed riding, real world. ran through over 2 tanks of fuel. between final carb tuning and changing ratio to 40:1, i yielded 38.2 mpg. :haw:
water temp out of the top of the radiator never went over 148, was 65 here yesterday??.
Im pretty happy with this. By comparison the fuel injected 170 4v was somewhere in the ball park of 42 and lived over 7k all the time.
I realised i should probably put the small luggage rack back on to haul oil. I have enough room under the seat to haul enough for almost 3 tanks but still, with a 1.6 gallon tank, thats not much.
Mechanically, i think shes sorted and reliable. Now its time to get on modifying the spare fuel tank to take at LEAST another .5-.7 gallons.
:vroom:
as a follow up, did a group ride sunday. 2 hours? or so, close to 100 miles (we of course made stops).
hit 85 at one point running down a triumph scrambler, surprised him pretty good when i passed him.
good day, zero issues, 34 mpg, water temp never went over 172, was 80 degrees out..
:cheerleader:
(http://www.2strokeworld.net/wp-content/uploads/GROM/250-conversion/GENERAL-AFTER-SWAP/20200503_141908.jpg)
Rightous!!! :metal: :metal:
How many wheelies does it do? All of them?
its not as nearly wheelie prone as you would think, i tired to avoid that with gearing, etc. however, it did launch it pretty good in 2nd gear coming out of a corner. it will come up shifting into 3rd pretty easy. :toot:
Sounds like giggling-in-the-helmet fun :bacon:
Sounds really cool! I have a clone version I've been eying for a swap. Didn't know about the counterbalancer in the Lt's - like it!
Just as an update, at around 6100 miles on the bike, it was time for the 3rd set of tires. swapped 1st set at 1500 miles to the power pures. they finally got hard enough for me to not enjoy them, so ordered a new set of city grips.
Had to recalibrate speedometer since the new ones ar e a slightly different diameter (130 now vs 140) and went out and saw dad.
after the initial issues i had, this thing has been rock solid since, for 2.5? years + now. :cheerleader:
(https://www.2strokeworld.net/wp-content/uploads/GROM/2022/291808635_5788011727893839_359427197418961679_n.jpg)
(https://www.2strokeworld.net/wp-content/uploads/GROM/2022/292112997_5788011471227198_1575470692915087611_n.jpg)
I legit ran out of road, but can hit 90..93 . if i tucked id get damn close to 100. if i regeared it, would be pretty easy but i have the smallest stock rear sprocket (rebel250) i can get on it.
:haw:
And it is still badass.
I know a 125 shifter kart is good for 105mph or so and they have awful aero. With 250cc you could get more than that I'd imagine, especially in that the aero has to be slightly better. That said, first gear would be good for like 40mph or something. Probably not practical.
Makes me wonder if they make a wide range stack for that transmission.
its a pretty close ratio out of the quad, and my intake system is absolutely dismal due to packaging, im probably giving up a solid 5hp there alone. also the high end of the rpm range is maybe... 8500? Now, if i went to like an RM cylinder, might be a different story.
I like it the way it is TBH. its def plenty. and thanks for the compliment. :gentleman:
You know I love a sleeper vehicle- definitely badass!! :metal: :olaf:
It is indeed badass, very well balanced and easy to ride like a regular person if so inclined.
Plenty quick and fast but totally manageable, less bananas than Jaime's 750, we'd all buy em if they made them that way.
I'm sure M can nitpick it but I dont remember anything other than it being a very fun bike. We'll, I think the speedo didnt wasnt done yet when I was on it but it is/was? totally unnecessary @ the gap, you are well aware that you are going faster than the legal limit.
Still waiting for him to find a new shiny object and need the space:) I'm afraid its a keeper tho.
lol. yeah the speedo was def a bit off on that trip. Also, that was when the stator took a dump the last day, easy fix though. Not chap but way better now.
Thanks for the kind words, it is a LOT easier and smoother to ride than most people think.
I remember being suprised at the number of people that declined your offer, its not like someone else is on the bike controlling your right hand.
Dead stator, meh, its an old engine, things break.
I've seen plenty of adults whisky flip the kids 80/85 goin up hills on the pipe, maybe thats where all the hesitation comes from.
Just saw one of the old yzs yesterday, the Gromdinger is about the same size, think yz sits higher but is softer.
I had a YZ85. those things are fkn gnarly. would pull 3rd gear power wheelies with me on it, dead stock. :devil:
I love it.
Not much of an update, this thing just keeps trucking on. rode it to work today.
while i can hit a faster top speed, I ran out of road and the gps (from phone to watch) lags, I saw 84 indicated.
I did throw in an iridium plug yesterday, and have a nology coil I added (had it leftover from the old 4 stroke setup). while it does nothing better up high as far as feel, down low it def idles cleaner and takes off better.
(https://www.2strokeworld.net/wp-content/uploads/GROM/2023/gromcommute-3-1-23_3.jpg)
(https://www.2strokeworld.net/wp-content/uploads/GROM/2023/gromcommute-3-1-23_2.jpg)
(https://www.2strokeworld.net/wp-content/uploads/GROM/2023/gromcommute-3-1-23_1.jpg)
Iridium plugs tend to be hard to read but water temp stays at 140-ish and no signs of being lean or too rich. This plug has maybe 15 miles on it.
(https://www.2strokeworld.net/wp-content/uploads/GROM/2023/gromcommute-3-1-23_3-plugchop-rotated.jpg)
I want one!