my Lightweight monospine RD350- weight thread and musings

[m in sc]

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.



as it currently sits:




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. 


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.

[SoCal250]

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!

[m in sc]

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.

[Czakky]

One of the coolest builds out there IMO.

[Dvsrd]

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!

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......

[m in sc]

yeah. im going to at some point weigh my stock r5, its going to be very close to an rd.

[Kawtriplefreak]

I have ridden it. It is sweet and it rips. The craftsmanship is superb

[Dvsrd]

Powerdynamo or HPI ignition? If HPI, how much lighter is it, compared to a Powerdynamo setup?

[m in sc]

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.

[Dvsrd]

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.

[retaRD]

Mark let's build some LIGHT wheels 

[Dvsrd]

Mark let's build some LIGHT wheels 

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.....

[m in sc]

Mark let's build some LIGHT wheels 

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

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. 

[retaRD]

Mark let's build some LIGHT wheels 

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

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. 

If you're gonna force me on it...

[m in sc]