Reunited with my RD350 after ten years.

[racewiththedevil]

Hey everyone. 

I was a member of the old forum years ago.  Just learned of how the old domain shut down and was brought back under new admin, guess that's why I needed to make a new username!  Really happy to see it has continued on and there's still a place to dig through all this useful info. 

Long story short - About 12 years ago, I bought a few bins of parts, a motor, and a couple frames from a guy in Rhode Island.  I turned all those parts into a complete 1975 RD350.  It didn't look like much but it was my first motorcycle, and it ripped.  Had a lot of really fun times with the bike in my early 20s, but eventually needed the money and ended up selling it to a guy a few towns over for a decent chunk of change.

My first ride on the bike many years ago:


Spent years regretting selling it, but I moved onto other projects (mostly cars) and life moved on.  Well, I happened to be browsing through facebook marketplace a little while back and there it was.  In the exact same condition I sold it in.  The guy just left it in his garage and never touched it for 10 years.  Got it back for $600... which was nearly as much as I payed just for the powerdynamo in it all those years ago    

ANYWAY -

Here's how it sits now:

Please disregard the messy garage.
KTM front suspension, LC swingarm with a cbr600 shock. Pretty sure i'll be sticking with the stock hubs.  Also got an aluminum gpz550 swingarm that I took in the pivot tube to fit the RD frame, so I'm also considering using that with dogbone linkage monoshock instead of the lc.

Mainly just mocking stuff up and deciding which route to go, very open to suggestions or recommendations!
 Tomorrow I will be shortening the ktm stem about an inch to fit nicely in the RD steering tube, then I'll start ordering some front brake parts.

[85RZwade]

Kawasaki and KTM parts in your Yamaha? The purists will be outraged, and I love it. Go, go, GO! Have fun with it.

[m in sc]

thats awesome.    welcome back. if oyu want oyur old username etc, pm me i'll see what i can do.

[SoCal250]

Welcome back! Congrats on getting your old back back. That's pretty cool, and it sounds like you come out way ahead on the deal. (Almost like the buyer paid you to store it for you for over a decade before returning it.)
Looking forward to seeing the project progress.

[racewiththedevil]

Brought my tig rig home from work to shorten up the KTM stem:



Welded out to flush then filed down any high spots just in case I'll ever need to change the bearing race, and since the tube is so thick on this particular stem I'm not worried about capping it. Fit perfectly on the RD tube.  Just gotta weld on some tabs for stops.  I also drilled out the RD dust cover to fit on there too, I think it makes it look a bit tidier. 

The finished product:




That's all for now - gonna order some brake parts and pickup some stock for wheel spacers to finish up the front end in the next few days.

[85RZwade]

Very sanitary installation and great work! From what KTM did you harvest that front end?

[m in sc]

yeah man, that's not going anywhere.    never saw a stem sectioned like that but makes all the sense in the world. I'll steal that idea down the road for sure. 

[racewiththedevil]

Very sanitary installation and great work! From what KTM did you harvest that front end?

Thanks! It's from a Duke 390 I believe.  sits about an inch higher than the RD front end without dropping the tubes in the triples.

[racewiththedevil]

yeah man, that's not going anywhere.    never saw a stem sectioned like that but makes all the sense in the world. I'll steal that idea down the road for sure. 

Yeah this is the best way I've found to do it.  Slugging it and doing a few plug welds also keeps it dead square while welding it out.

[Kawtriplefreak]

Welcome back!!Beautiful work.

[racewiththedevil]

Got out of work a little early and started messing around with stuff.  Didn't take any pics modifying this swingarm unfortunately, but ultimately I narrowed the pivot tube pretty substantially, sourced some needle bearings and seals, and used a shaft from an SR500.  What do you guys think about this vs the RD350LC swingarm?  I'm leaning towards this, even though it extends the wheelbase a little bit.  Alloy arm.. definitely better suspension... I kinda think I have to go this route, mainly because of how surprised I am that it fit in the tiny RD frame 

Not to mention, I don't think fitting up the mounts for the dogbone/upper shock will be too bad at all.  Just gotta mess around with different linkage options.

[rdshaw]

Got out of work a little early and started messing around with stuff.  Didn't take any pics modifying this swingarm unfortunately, but ultimately I narrowed the pivot tube pretty substantially, sourced some needle bearings and seals, and used a shaft from an SR500.  What do you guys think about this vs the RD350LC swingarm?  I'm leaning towards this, even though it extends the wheelbase a little bit.  Alloy arm.. definitely better suspension... I kinda think I have to go this route, mainly because of how surprised I am that it fit in the tiny RD frame 

Not to mention, I don't think fitting up the mounts for the dogbone/upper shock will be too bad at all.  Just gotta mess around with different linkage options.

I use a adjustable tierod and bellcrank system for the top mount giving a lot of options for suspension forks and shock!

[m in sc]

take a look at how an rz is set up. easy compact solution. 

[sav0r]

If i were doing this, the first thing I would do was remove the spring from damper and measure motion ratio on the original bike. Moving that top eye even a little bit can have crazy changes in effective wheel rate. It seems simple, but there's a lot to unpack there. I'd use a dial indicator on the damper to measure travel, then place .25" plywood shims under the wheel (adding one each measurement to like 3" of travel), then plot the change in ratio on a graph. Then I'd mount the new setup to get as close to possible as stock. That setup is going to get progressive real fast, but I would be willing to bet thats where they keep it in stock form.

[TPR5]

Dude great project !!