350 2 stroke motor (basically) from new. (for the gearheads)

[m in sc]

this is for the gearheads.

this is a 73 RD350 bottom end ive had for a long time, and it was just a spare. for one of my bikes, i wanted to do a full bore refresh with everything new, including ALL hardware, crank (banshee style), clutch basket (billet), etc. This motor had maybe 1500 mile son it before a previous owner a long time ago melted down the LH cylinder. there is zero wear in the transmission but even that got all new bearings etc. I bought this motor in a batch sale of motors, were 7 in total probably around 2015. This had been sitting in a bike outside and was so caked with mud on the underside you couldnt even see the lower webbing.

why? I have a set of cylinders out being ported by one of the last great engine tuners from the 70s (as a favor) and will be in the 75-80 rwhp range with this setup. Im currently around 72 at the crank with current motor.

Time to go big or go home (stock these had about 34 at the rear wheel).

post initial cleanup at home. this is 2 hours of scrubbing and lots of really nasty chemicals:

new billet clutch basket and cush drive

some of the new hardware.

picking up cases from vapor blasting on my 72 T500 ( i did bring them there on the trail)

back from the cleaning.

transmission, shift drum and a forks etc in.

underside, all the nuts are black stainless.

topside: again, all new stainless hardware.

Brand new crank. not nos, brand new. runout was almost perfect, well under spec. one spot just tipped the dial gauge at 0.0005" on my truing stand (yes that's the correct # of zeroes) for a split second (about 20 degrees of rotation).

earlier this month i also did a hydraulic clutch slave cyl upgrade (had an old aprilia one that was getting long in the tooth, i put it on back in -8 or so? to this one, and made a new adapter. this is all 100% reversible bolt in.

this is the recipient. This project will be 20 next february. Ist still running riding great now as it is.

 

[Little_Thumper_Boy]

Beautiful work, looks like a real fun project. It'll be rewarding when it's dyno'd and you see those RWHP numbers happen. Even more rewarding to ride it!

 

[m in sc]

thanks. yeah, its just some (real) final refinement & def wasn't necessary. but, it sort of was... if that makes sense.

 

[G19Tony]

thanks. yeah, its just some (real) final refinement & def wasn't necessary. but, it sort of was... if that makes sense.

If it's worth doing, it's worth overdoing.

 

[m in sc]

that sort of defines this whole bikes ethos. its pretty ridiculous.

 

[m in sc]

still going on this but light at the end of the tunnel. I shelved it to do some minor projects, BBK on the XR, and other stuff here and there on other bikes, like the KZ, etc. But now, its back front and center.

I drew this up and hat it printed, the y-boot for the airfilter. there no joined intake for carbs this big available that will fit in a stock dimensioned frame, and i wanted to redesign the old one a bit . this should do the trick.

whipped up a 90 degree water inlet for the cyl head at lunch one day, to move the coolant hose position

cyls are being bored now, new pistons arrived so hopefully will get back friday or monday. forged wossners going in this time.

also finishing up the mock-up. all ready to go when parts arrive mechanically.

since i basically had a week to kill, had a huge scratch to repair ont he tail from a 2015 crash, so I spot filled, used some of the original paint(ford wimbledon white) and touched up, wet sanded/blended and cleared.

 

[Salty Sway]

Thanks for sharing! Awesome build. Don't see to many sets of Works Performance shocks these days, I've had a few RDs over the years and they were a lot of fun. Please continue to update.

 

[m in sc]

thanks. they are still around actually, his daughter is running the company under a modified name, worxshocks, although the website is trash and unsecure.
Address: 7861 Alabama Ave Suite 12, Canoga Park, CA 91304
Open ⋅ Closes 1:30 PM
Phone: (818) 701-1010

I have 6 roadgoing (running riding.. except this one for the moment) yamaha twin 2 strokes, of which 4 are variants of rds. i've owned.. many. this one has been around since 2004.

 

[m in sc]

wrapped it up Saturday before i headed out of town on vacation. did a few test rides. here's the actual 1st fire up

 

[Salty Sway]

That's awesome, love the sound of a two stroke