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The 2-Stroke Garage => Haus of Projects => Topic started by: m in sc on April 08, 2019, 11:45:57 AM

Title: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 08, 2019, 11:45:57 AM
So, since the thread is lost to time, I will start a new one as Im basically finished.

it started as this, a sweet 4130 frame built by danny (27 cycles) we collaborated on, and he did a fan-fucking-tastic job on.

(http://www.2strokeworld.net/wp-content/uploads/lightweight-rd/featherlight-frame-arm_10_zpsiwylsnoy.jpg)

as it currently sits:

(http://www.2strokeworld.net/wp-content/uploads/lightweight-rd/TI-fender-hl-ears/rdftfender-ti_5_zpsk7vouaxd.jpg)


the target goal was , arbitrarily, 235 lbs. Just a sort of a guess of where i think i could get it.

I weighed it at wheelers shop at deals gap 3 years ago, came in at 261. way out of line. changed a BUNCH of things, the next year it came in at 246 with a gallon of fuel.

This was pretty good, but wanted to do more to get to goal. I also chased all SORTS of weird tuning issues. I finally got all that sorted out after a few years. Stuff i never have issues with, but thats another story.  :bang:


so, being very skeptical of the scale at the bike shop,(its an outside unit, just old and im sure hasn't been calibrated in a decade or more) I wanted it measured on a certified scale . so happens a friend of mine works at a metal fabrication house ( mass production stuff) and just had their scale calibrated.

I know, for a fact, over the past year i have shaved over 6 lbs off just in comparative components changes (weigh one vs the other and swap), plus all the titanium hardware ive swapped onto it. there's been a LOT.

The final weight, no fuel, on a certified scale, is 245 lbs with no fuel. But otherwise ready to ride.

I'm extremely happy with that.  I'll continue to shave oz here and there when i get the bug to do do, but not an all out assualt on mass reduction as i was for the past 10 mos.

I've read stock weight numbers from 340-378 lbs., including some old books and articles, etc the 378 lb number from the guy that built the 'brew dude' bike, and also claims his is 2 lbs lighter than mine (of which i dont believe the 1st number, and skeptical of the 2nd number.. but then again, it has no lights. Mine has full running gear).

From what ive read, it seems 355-360 seems to be about the consensus for a stock rd350 ( a or b). does anybody actually have a stock weight, from a scale? not an article.

I'll have it at the gap this year, again. Since i got the issue sall sorted out (fingers crossed), it should be a good trip.


(http://www.2strokeworld.net/wp-content/uploads/lightweight-rd/webco-heads-rprd/rprd-superior-_monospine-11_zps8o0svs72.jpg)







Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: SoCal250 on April 08, 2019, 12:27:57 PM
Quote from: m in sc on April 08, 2019, 11:45:57 AM
From what ive read, it seems 355-360 seems to be about the consensus for a stock rd350 ( a or b). does anybody actually have a stock weight, from a scale? not an article.

Mark, you don't think the Yamaha factory spec weight is correct?  The weights in your post above seem to be quite a bit more
RD350B: 315 lbs dry 
RD250B: 309 lbs dry
RD400C/D: 342 lbs dry

245 is damn light! :science:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 08, 2019, 12:57:02 PM
To be honest, not really. I mean looking at period tests they were all over the place weight wise. what i need to do is weigh a stocker, i have access to one but would be a while before i could get it up there.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Czakky on April 09, 2019, 08:45:18 PM
One of the coolest builds out there IMO.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on April 19, 2019, 08:29:01 AM
Quote from: SoCal250 on April 08, 2019, 12:27:57 PM

Mark, you don't think the Yamaha factory spec weight is correct?  The weights in your post above seem to be quite a bit more
RD350B: 315 lbs dry 
RD250B: 309 lbs dry
RD400C/D: 342 lbs dry

245 is damn light! :science:

The factory numbers would be absolutely dry, that would be no fuel, no gear oil, no forkoil, no brake fluid, and NO BATTERY. So not anywhere near the actual curb weight......
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 19, 2019, 10:08:31 AM
yeah. im going to at some point weigh my stock r5, its going to be very close to an rd. :cheers:

Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Kawtriplefreak on April 19, 2019, 10:30:18 AM
I have ridden it. It is sweet and it rips. The craftsmanship is superb :patriot: :patriot:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on April 21, 2019, 01:16:31 PM
Powerdynamo or HPI ignition? If HPI, how much lighter is it, compared to a Powerdynamo setup?
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 21, 2019, 08:57:05 PM
hpi now. compared to a banshee cdi its almost 4.2 lbs lighter if i recall. i never weighed it compared to the powerdynamo. i think it came in at 2.4? lbs. i had a picture somewhere cant find it right now.

i remember, the heads came in, thay added almost ~2 lbs, but the ignition dropped 4 ish, so it was a net savings of around 2.2 total.


Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on April 22, 2019, 09:17:45 AM
Quote from: m in sc on April 21, 2019, 08:57:05 PM
hpi now. compared to a banshee cdi its almost 4.2 lbs lighter if i recall. i never weighed it compared to the powerdynamo. i think it came in at 2.4? lbs. i had a picture somewhere cant find it right now.

i remember, the heads came in, thay added almost ~2 lbs, but the ignition dropped 4 ish, so it was a net savings of around 2.2 total.
I just checked the VAPE webshop, the PD kits kome in around 2.3 kg or 5 lbs. So the HPI definitely saves some weight.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: retaRD on April 22, 2019, 12:21:54 PM
Mark let's build some LIGHT wheels  :haw:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on April 22, 2019, 03:09:27 PM
Quote from: retaRD on April 22, 2019, 12:21:54 PM
Mark let's build some LIGHT wheels  :haw:
3 options, maybe?
Lighter hubs, alloy rims, and butted ss spokes, maybe alloy spoke nipples. Downside is need for inner tube.
Magnesium wheels. 18" would most likely be older cast TZ race wheels. I guess forged magnesium would only be available in 17" ?
Carbon fiber would be optimal, but hardly available in suitable sizes. Although Blackstonetek do make 19" flat track wheels.....
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 23, 2019, 08:47:18 AM
Quote from: retaRD on April 22, 2019, 12:21:54 PM
Mark let's build some LIGHT wheels  :haw:

i do have a few spool mx hubs in my possession for the rear.   :devil:

nathan, when you ride it in a few weeks, you may rethink. its almost -too- light. i was riding it around sunday and its pretty ridiculous. you'll see.  :metal:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: retaRD on April 23, 2019, 01:16:32 PM
Quote from: m in sc on April 23, 2019, 08:47:18 AM
Quote from: retaRD on April 22, 2019, 12:21:54 PM
Mark let's build some LIGHT wheels  :haw:

i do have a few spool mx hubs in my possession for the rear.   :devil:

nathan, when you ride it in a few weeks, you may rethink. its almost -too- light. i was riding it around sunday and its pretty ridiculous. you'll see.  :metal:

If you're gonna force me on it...
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 23, 2019, 01:37:45 PM
 :tough:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on April 29, 2019, 08:48:47 AM
Quote from: m in sc on April 23, 2019, 08:47:18 AM
I do have a few spool mx hubs in my possession for the rear.   :devil:

Most interesting. Any hint of what MX hubs are easy conversions? Preferably with a cush drive....
For My XS650 project, I ordered a new "Talon" brand KTM 500 hub, and had Central Wheel in the UK lace up a wheel with SS spokes and a 2 1/2" unflanged Morad alloy rim. Flanged rims look better, but are harder to keep clean
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on April 29, 2019, 11:49:46 AM
i have some cr hubs available. i havent tried to be honest, they are just sitting on my rack at work.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on May 09, 2019, 01:10:25 PM
Quote from: Dvsrd on April 22, 2019, 09:17:45 AM
Quote from: m in sc on April 21, 2019, 08:57:05 PM
hpi now. compared to a banshee cdi its almost 4.2 lbs lighter if i recall. i never weighed it compared to the powerdynamo. i think it came in at 2.4? lbs. i had a picture somewhere cant find it right now.

i remember, the heads came in, thay added almost ~2 lbs, but the ignition dropped 4 ish, so it was a net savings of around 2.2 total.
I just checked the VAPE webshop, the PD kits kome in around 2.3 kg or 5 lbs. So the HPI definitely saves some weight.
I emailed HPI, asking for total system weightm incl RR. They replied 1.300 kg, so 1 kg or 2 lbs 4 oz lighter than PD/Vape. Which in itself is at least 2 kg less than oem alternator/ignition/R&R for a points RD.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on July 21, 2019, 09:36:20 AM
between the coil, and the box, regulator, wiring, etc, i know it was ~4 lbs (this was also a 200w aftermarket banshee unit i replaced). Over all doesn't matter, as I added 2 lbs back with the heads. lol.  I weighed it all at work on our scale , i have pics somewhere.


anyway,

few days ago i ran across a post from the uk aircooled group, guy selling aluminum rd head bolts. figure its been a while since i 'added lightness'. while id prefer titanium, my project budget has been slightly diverted in part to other projects, so i got these instead.  i think they cost me around 10 bucks each, posted from the UK.

:haw:

Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: teazer on July 21, 2019, 11:33:33 AM
Good choice.  TZ motors all run alloy sleeve nuts (anodized blue but they fade). I don't remember what the TD3 used.  Maybe Lyn can tell us.

I bought a set of alloy sleeve nuts for my GT750 drag bike from the UK.  They were anodized black.

Do you have a link for those?  I will need some if I change out the RD/TZ hybrid motor for an air cooled RD400 based motor.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on July 21, 2019, 03:24:23 PM
guys name is ‎Jeffrey Newton‎ , uk rd aircooled club, look him up on FB. hes also a friend of Derek Freegards.

Yamaha Aircooled RD Owners Club

https://www.facebook.com/groups/44878139642/?fref=nf
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on October 12, 2022, 08:24:12 AM
Quote from: m in sc on July 21, 2019, 03:24:23 PM
guys name is ‎Jeffrey Newton‎ , uk rd aircooled club, look him up on FB. hes also a friend of Derek Freegards.

Yamaha Aircooled RD Owners Club

https://www.facebook.com/groups/44878139642/?fref=nf
Still happy with these alloy head bolts (sleeve nuts?)
I just sent Jeffrey a message regarding these.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on October 12, 2022, 08:25:42 AM
Yes. hes a bit prickly to deal with but they are beautiful and holding up well.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on October 12, 2022, 08:48:02 AM
Quote from: m in sc on October 12, 2022, 08:25:42 AM
Yes. hes a bit prickly to deal with but they are beautiful and holding up well.
BTW, congrats with the TZR purchase! Those are indeed beautiful bikes!
Anyway, back to the RD and these alloy head bolts: What type of head gasket do you use? O-rings, 350 style copper or 400 style copper?
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on October 12, 2022, 09:06:38 AM
when i had the 'stock' modified heads, used 400 gaskets , chuck set them up for it. on the webco/rprd heads, they are o-ringed.
and thanks, that tzr makes me very happy.  :bacon:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: JB Weld on October 14, 2022, 11:17:30 PM
Gosh I remember the posts from the old forum about this build. Love it!! Might be blasphemy, and I wouldn't do it, but what about drilling some holes in the head fins? Might get some of that added weight back.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on October 15, 2022, 06:18:35 AM
Quote from: JB Weld on October 14, 2022, 11:17:30 PM
Gosh I remember the posts from the old forum about this build. Love it!! Might be blasphemy, and I wouldn't do it, but what about drilling some holes in the head fins? Might get some of that added weight back.

I still have titanium axles i havent put in yet, probably wont. I gained 2 putting the heads on, but lost 4 going from a banshee cdi to an hpi, so im ok w that. lol. its almost too light at this point. (riding it that is).  :haw:

I did swap the top triple tree last year, used this unit from 'speed of cheese' (see the vendor section).
(https://www.2strokeworld.net/wp-content/uploads/lightweight-rd/cnc-tripletree/cnc-tripletree_6.jpg)


old:
(https://www.2strokeworld.net/wp-content/uploads/lightweight-rd/cnc-tripletree/cnc-tripletree_2.jpg)

new:

(https://www.2strokeworld.net/wp-content/uploads/lightweight-rd/cnc-tripletree/cnc-tripletree_1.jpg)

currently at 241 lbs with gas in it.

Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on November 01, 2022, 03:20:49 AM
What front brake setup do you have? "Blue Spot" caliper and floating disc? And what does disc and caliper weigh?
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on November 01, 2022, 10:16:10 AM
believe the caliper is from an FZ1, rotor is from an fzr600. as far as weight... its  a LOT lighter than a stock one, thats all i remember.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Dvsrd on November 01, 2022, 10:34:22 AM
Quote from: m in sc on November 01, 2022, 10:16:10 AM
believe the caliper is from an FZ1, rotor is from an fzr600. as far as weight... its  a LOT lighter than a stock one, thats all i remember.
Thanks! On my 350, I have a drilled stock disc (saves maybe 150 g) and an alloy repop caliper from EC. Caliper is great, and a lot lighter than stock. I am considering a custom ISR disc for the stock carrier, but the weight saving potential is limited to 450 g/ 1lb or so, due to the pad track width. Going to a 4 pot caliper would allow a much lighter disc, even at a larger diameter. Will have to ponder this a bit......
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on November 01, 2022, 10:35:43 AM
its a fantastic proven brake setup. also can use an 11mm master cyl.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: TPR5 on November 23, 2022, 10:16:35 PM
Very cool
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: oxford on November 24, 2022, 11:21:17 AM
Quote from: Dvsrd on November 01, 2022, 10:34:22 AM
Quote from: m in sc on November 01, 2022, 10:16:10 AM
believe the caliper is from an FZ1, rotor is from an fzr600. as far as weight... its  a LOT lighter than a stock one, thats all i remember.
Thanks! On my 350, I have a drilled stock disc (saves maybe 150 g) and an alloy repop caliper from EC. Caliper is great, and a lot lighter than stock. I am considering a custom ISR disc for the stock carrier, but the weight saving potential is limited to 450 g/ 1lb or so, due to the pad track width. Going to a 4 pot caliper would allow a much lighter disc, even at a larger diameter. Will have to ponder this a bit......

You can save a little more weight with your setup if you get some aluminum pistons for the caliper from Eric at oily pipes gang (202wagon). The stock rotor can also be thinned  down, I would have to measure them but iirc I took mine down to 5mm.  The carriers can also have some material removed but it's not a huge weight savings in them.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on August 29, 2023, 03:17:33 PM
incidentally, i just sent somebody a link to this thread. forgot to update, it sunder the target weight dry now (weighed at gap this year again). was right at 241 with 1.25 gallons of fuel in the tank, which puts it under 235, barely.  :patriot:  :metal:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 04, 2026, 01:14:29 PM
update.. haven't changed much on this for a while.
Last year I did change over to a 4 wire voltage reg/rectifier to smooth out idle lights (was all ac off the vape HPI). that worked out quite well. Anyway, went ahead and had it out Friday after work, and rode it home. while sitting and staring at it, decided to see if a generic seat i had bought from Snorklefork on here might fit.. and, hours later.. (it was quite an endeavor actually), i got it on. last 2 pics show the reg/rectifier and a before Pic. the silver doesn't match at all, but I can live w that for now. the only parts painted on this bike w 'color' are the engine covers, cyls, fork brace/fender mount, headlight bucket.. and now seat cowl.  everything else raw or clear coated. 

also. Unintentionally, the longer seat is actually lighter by a hair, as it doesn't need the aluminum support pan the smaller one did.  :clap:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: RDryan on January 04, 2026, 01:36:29 PM
Looks nice. I bet that bike rips. :vroom:  So correct me if I'm wrong, you say your running it with the Vape ignition? Now in that last pic it looks like a different brand regulator/rectifier. Am I correct to assume that? and if so I guess it's OK to do that? I was always under the impression that the Vape regulator rectifier was recommended to be used with the rest of their ignition system I guess to maintain a reliable optimum functioning set up. Me being a "electrical dummy" I just assume that to mean that using a different brand reg./rec. would possibly fry the Vape coils or something like that.


P.S.- I guess I should be more thoughtful prior to posting. It does look better with the new tail/sea setup. Is it more comfy?...I wonder if it's heavier?
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 04, 2026, 03:18:17 PM
actually, I typoed.  its an hpi. but yes you can run a different reg/rectifier on either vape or hpi. the hauling requires floating a ground to make it a 2 wire ac setup. but ac is ac. I run 4 other bikes with vape so, sorry, muscle memory.  thanks, and yeah its really quick. 50+hp on 236-240 lbs wet weight
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: quocle603 on January 04, 2026, 03:31:14 PM
What a nice mod wit that part you purchases from that other member.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 11, 2026, 01:57:50 PM
changed the tail light for something a bit more... stylish, and visible, and the slight chrome ring actually ties in w the headlight ring, sort of.

either way, since i now have my own 3d printer at home  :devil:  i made up the adapter and mount.






Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Kawtriplefreak on January 11, 2026, 02:40:10 PM
Righteous!
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: X-Man on January 13, 2026, 10:38:59 AM
That is a such a great looking seat and tail section. Totally fits the look of the bike. 

Now please tell me more about that rad CT in the background.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 13, 2026, 01:02:10 PM
thanks. that is a 21 I bought new. its not 💯stock but nor ridiculous either
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: JKV45 on January 13, 2026, 01:48:23 PM
Nicely done printing on the adapter and mount.
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 13, 2026, 02:53:59 PM
thanks.  I do this stuff at work a lot so this type of part is pretty straightforward.  but having my own printer at home def makes it easier
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: 350GUY on January 13, 2026, 10:43:01 PM
Niceee
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 19, 2026, 12:16:48 AM
went ahead and drew up and new hl bucket that integrates the endurance speedometer and the hl switch but uses the 'original' TY 175 hl ring. pretty happy the result. did a rough test print in abs, then some adjustments, then final in pteg.

Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Kawtriplefreak on January 19, 2026, 08:37:02 AM
 :metal:  :metal:
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: RDnuTZ on January 19, 2026, 10:09:34 AM
:olaf:


where's the pink bathrobe?
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: JKV45 on January 19, 2026, 10:24:43 AM
Nice!

Pretty handy to be able to make up custom parts that don't otherwise exist!
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: m in sc on January 19, 2026, 09:21:10 PM
thanks. yeah, got it installed.

seems to be pretty good. very happy w result.  :afro:

Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: Kawtriplefreak on January 19, 2026, 10:47:12 PM
Very nice!
Title: Re: my Lightweight monospine RD350- weight thread and musings
Post by: 85RZwade on January 20, 2026, 09:38:42 AM
It's perfect, but it'll have to do.