'73 Yamaha RD350, Start to Finish

[RLloyd]

So, been lurking these forums a long time but have never really contributed anything. I noticed the explosion of 2 stroke builds here recently and decided it was time to throw my hat into the ring. Here's the documentation on a '73 RD350 I got as a nearly non-running booger back in June. Came to me with a horrible base gasket leak, terribly ragged out top end, rusted out exhaust, non-working electronics and about 10 years worth of caked on dirt. I got it from this girl who owned it about two days and bought it from some meth-head. "Finished" it up about 2 weeks ago and have been enjoyed the hell out of it ever since.

Here the bike is on it's first day home, sitting right in front of the CB350 that had to get sold to make some room on my back porch workshop

And here's a photo of just the RD, mid teardown. It's a shame I didn't take any closeups so you could see just how shagged out the bike was

 

[RLloyd]

So, first things first, got the bike all torn down and detabbed the frame

Meanwhile, rebuilding the engine. The points were pretty far gone and I didn't really feel like messing with them anyway. They're pretty notoriously finicky on the RDs. Got a really nice Dyna ignition from Nick at Vintage Smoke. Solid dude! The polished fins on a stock RD look pretty nice, but everyone's bike looks like that. I decided to black it out.

 

[RLloyd]

Next, found a new set of wheels since there were huge dents in the front and back rims that came with the bike. The hubs and spokes got the same flat blat treatment as the engine. Decided to do a colored frame, but wanted to keep it kind of muted, so I ended up going with Dupli-color "Chrysler Forest Green." Here's a shot where you can see how the color turned out pretty well

This is about the time that Austin was topping out around 110 degrees everyday. Cleared it with the GF and the build moved inside. Next I got the steering damper installed, the forks rebuilt, and then did an initial mock-up with the engine and exhaust to see what I was working with

The pipes are Spec II F1s. Love those things.

 

[RLloyd]

I was pretty excited that things were starting to come together, so the pace picked up a lot at this point.

Found a nice drilled brake rotor on one of the 2 stroke forums. Switched from the stock master cylinder, which was trashed, to a real mint one off a CBR600

My stock wiring harness was trashed with weird connectors and electrical tape nightmare splices everywhere, so I binned it and was gifted a new one from a buddy.

Installed new coils, a new regulator/rectifier and made a nice little hiding place for the battery under the rear of the tank out of my old flasher relay mount/tool kit holder

Got the carbs cleaned up and reinstalled them along with Banshee manifolds with a cross-over and my stock reed cages with the center bars milled out and TDR racing reeds installed. Intake is a rubber Y-boot with a K&N filter.

 

[RLloyd]

The last couple of things I did in the air conditioning before the bike moved back out into the Texas heat that just won't quit

520 chain conversion

Fabbed up a new tail light/license plate bracket out of some road sign metal

Relocated the key switch to the headlight bucket since we're doing away with the nasty looking stock gauge cluster

Got my Acewell installed and working. It's kind of sticking way up here and in all my other photos -- I finally figured out a decent way to get it mounted flush with my top triple the other day

And here it is, more or less ready to roll back outside

 

[RLloyd]

So, up next was installing the rearsets, bending the kickstarter to clear them and rolling the bike outside for some tune up and break-in

 

[RLloyd]

And then, finally got the bike out in the driveway making some smoke. This video is from right after the first start up -- just doing some heat cycles, no heavy revving or anything. I've since gotten the idle to come way down. She ticks over really nicely now. These bikes are so much damn fun. If you've even been vaugely considering picking up an old 2 stroke, DO IT.

1973 Yamaha RD350 Running At Last

 

[PatDoody]

nice little build. are you running premix?

 

[clem]

Dang these two strokes! I gotta get one. Reminds me of my motocross days. HOw do these things compare against a 250cc moto two stroke? Is the power comparable? Last one I had was a 2001 CR250 and it was a pretty quick. Would be cool to get the same feeling on the street.

 

[JustinLonghorn]

Yes sir. I can dig it.

 

[Autotek]

Pretty awesome job, the two strokes are sweet. I would probably add a fork brace to keep the front end as solid as the back with those new shocks. The older bikes need them to keep the forks working together and not independently!