RD350 Project Mustakrakish

[bostontrackrat]

Wiring seems so far so good.  I hooked up a battery in the system where the output from the Reg/Rec would be (I'm running a batteryless system) and everything seems to work as intended.  Wont know 100% for sure until I get the engine to fire up.

I got my chain and sprocket from Economy yesterday and just went to install it.  Sadly, I'm coming up short.



I counted, it's 92 links, which is what's supposed to be for an RD350.  I emailed Economy to ask them for their thoughts.   I have a 14T front and 43T rear sprocket, which is huge, but it's what I had laying around.   So I'm wondering..... am I unable to close the chain completely because the 43T rear sprocket is just way too big?  Or is it possible I accidentally acquired an RD400 swingarm?  Does anyone have the front to back dimensions for either swingarm?  I know the 400 is longer but I dont know the dimensions to be able to confirm what I have.

So now I'm trying to figure out if I need to buy a smaller sprocket, a longer chain, or both?

[bostontrackrat]

So I went ahead and ordered up a longer chain and another sprocket to try out, on the recommendation of the guys at Economy Cycle.  In the mean time, I have other work to do.

I completely cleaned up the inside of the left side cover, and cleaned and lubed the clutch actuator.  (forgot to take an after pic)



cleaned and painted the ignition cover and center stand.



Installed all the cables.  Installed new fuel lines and clamps.   I still need to plug up the oil injection ports because I'm running pre-mix (for now, I'll add the pump back in later).



And finally, joyfully, the final touch.... putting it up on its own center stand and installing the exhaust.



That, my friends, is a complete motorcycle!     I just put oil in it and I'm heading out now to get some fresh gas!  Hopefully I can get some noise out of it today.  Wish me luck!

[bostontrackrat]

She made smoke and noise for the first time in over 3 decades today.  Very pleased.   

As you can see, it's running terribly and will not idle.  I way over-shot on the jets, and I'm beginning to dial it back.  But hey, it ran!

I'm struggling with the timing on the Vape system.  I've read and re-read Chuck's thread multiple times now.  My issue is the timing marks arent matching when it's stationary and when it's running.  I'll take some pictures later to try to explain.

[quocle603]

That's some good old smoke. You running a stock system?

[bostontrackrat]

That's some good old smoke. You running a stock system?

Stock exhaust with baffles removed. Stock carbs. Vape ignition.

[quocle603]

Not sure if this may help but here are my settings for my RD350 with Yboot and Uni filter.

VM28SC without mod.
Main: 240 (might go down to 235-230)
Pilot: 30 (might increase to 32.5 or 35)
Airmixture: 1 1/2 turns out.
Clip: 3rd position

[bostontrackrat]

Much appreciated Quocle! I forgot to mention that I also have the Y boot with the Uni, and I have not done the Dave F mod either.   So hopefully your settings will get me on the right path.  I had a 180 main jet in there, and was worried it might be too rich.  You're really running a 240? 

[JB Weld]

Not sure if this may help but here are my settings for my RD350 with Yboot and Uni filter.

VM28SC without mod.
Main: 240 (might go down to 235-230)
Pilot: 30 (might increase to 32.5 or 35)
Airmixture: 1 1/2 turns out.
Clip: 3rd position

Second guessing where my jets are right now. 65mm ProX pistons, TDR reeds, 1/4" spacers, rz intakes, individual uni pods, Dave F mod and DGs. I'm running 180 mains, 32.5 pilots on the third clip, 1.75 turns out. I can't wait to start messing with the carbs again next year.

I'm not 100% happy with my jets right now, but it's close. Probably an air screw adjustment, larger mains and change needle position. I have no noticeable flat spot which is amazing!

[quocle603]

Yeah, without the Dave F mod, you will be around the 220-240ish(+/-) range for your main. With your new filter, you're adding a ton of air into the mixture and you will need to compensate with larger jets. Obvious ride and try to grasp what the bike is telling you. Obvious start with a richer and go leaner.

[bostontrackrat]

Well bad news.   I took the bike out to an empty parking lot over the weekend and got it fired up.  I thought maybe it just needed to clear it's throat for a few minutes in order to get it to idle.



Got it fired up under about half throttle.  Wont idle but I can keep it under part throttle (not full), and give it little blips and it kept running, but was real rough.  Then, after about 2 minutes of running, instant silence.     Go to turn the engine over with the kickstarter and it's totally seized.   

I decided to put it back in the truck and take it home for the day before I decided to throw it in the river.

So, I'm sad to say this marks a significant pause in forward progress on this project.  I'm moving next week, so I'll need to focus on that for the next few weeks, getting the house and the garage setup and whatnot.  Then I'll pull the motor and inspect it.  Stay tuned!

[quocle603]

Yikes! The oil pump not work or something? You were clearly getting some oil before (from your video). This is concerning...

[bostontrackrat]

33:1 premix :/

I passed a leakdown test before starting it.   Either I have a serious problem with carbs or ignition timing, or....

The crank shaft that I didnt rebuild and said "seemed to be in good condition", wasnt.

I talked to a buddy of mine who runs a really good vintage repair shop and he said because I only ran it for about 2 minutes under no load, it seemed unlikely that the piston would get hot enough to seize.  He thinks the crankshaft had a toasted bearing that I didnt notice.

[quocle603]

Check your clutch and generator side to see if anything is binding it. 

Take off the top end to see if anything is binding. Inspect the top end, check if your circlips are still in your pistons. I had a mysterious circlip show wedge between my crank and case.

Good luck man. It would be unfortunate if it's the crank :(

[bostontrackrat]

ZOMBIEEEEE THREADDDDD!!!!!!!   

Back from the dead and back at it!

It's been a long 2021 so far and I havent had a moment to turn a wrench on the RD since my last post in October.  My wife and I bought a house, moved, and have been very busy settling in and setting the place up.  Then this spring was all busy with me running the Honda Hawk Gt at a large variety of track days and race orgs.  I was on the track 4 weekends in a row at one point.  With other projects stabilizing it's time to pull the RD350 back up to the workbench and see what's gone wrong.



First order of business was getting the engine out of the bike and onto the bench, went much faster than expected.



I got the side covers off, and the top end off and guess what....?

Rotating assembly spins smooth as silk.

Now what?



The only anomaly I've been able to find is these 2 score marks on either side of the exhaust port that coincides with slightly flattened worn marks on the piston rings.  Pressure points of some kind.  I pulled the rings off the piston and checked the end gaps again and I have plenty.  So I've chocked this one up to installation error.  I probably didnt have the ends centered perfectly around the locating pins, so I put them back together extra carefully.



A quick annealing of the head gaskets on the stove when my wife wasnt looking.



And back together the top end goes.  Quick pic of the cool little Pro Flo mark from when the head work was done.

I'll let you know when it's back in the bike.



I'm also VERY excited to announce a new addition to the fleet.  A fully race built RD400 that I'll be racing in USCRA in 2 weeks time!  This thing is built to the nines and runs like a top, should be very interesting.  This is going to be my first time actually riding a large 2 stroke bike, and it's going to be on the race track!

Quick specs:  Fully built motor with heavy duty porting, squish/compression work, running on race gas, expansion chambers look similar to Millenniums but cant say for sure, Worx shocks and Race Tech fork internals, and a modern master cylinder, all rolling on R-compound Heidenau tires.

[Czakky]

That 400 sounds like a blast. Keep us posted.