27th Jun 2010, 18:22

A real cheap fix for the fouled plugs is two old school 12v automotive coils (you know the black ones that are about the size of a soda can) and use hose clamps to mount them to the frame down tubes in front of the motor. $20 and super easy. Lift the tank, disconnect the leads from the stock coils, reattach them to the new coils, and I think the stock plug wires were a perfect fit. This was back in '78, so I may have replaced plug wires too and just forgotten about it.

I still miss mine!

7th Jul 2010, 15:41

I still own both my RD 350b's. One is a stocker and one is tricked out. Bought one in 1977, the other in 1981. I'm gonna be 52 this year, and don't think I'm ever gonna sell them. Always had a lot of fun with all my buddies on their RD's too. Lots of good memories. I raced a lot of other bikes too. I beat almost all I tried too. Now I need to get them running again!

16th Nov 2010, 16:44

My friend bought a slightly modified RD350 last year with DG pipes. He let me ride it 1000+ miles to the upper peninsula of Michigan, and grew very fond of the bike. Several months ago I purchased it from him when he got fed up with an electrical gremlin that occurred later in the season.

I spent nearly 100 hours fixing and modifying it, and traced the problem to a ground in the throttle grip. I've got it running now, ported, Big Reeds, VM30's, still have the DG pipes. Have a friend able to dyno tune it for me, my guess its between 40-50hp. Have had it to 115mph with a +1 engine sprocket and -1 rear, straight as an arrow.

I'll forever have this or an RD350, there is nothing like being at a stop light and everyone questioning what you're riding on. My name is Sean Byers from Livonia Michigan, I hope I read this years down the line and still have my RD.

Long live the RD350.

8th Dec 2010, 08:13

I had a 1980 RD400, I loved that bike :-) When I got on it, I felt like I was getting into my own spaceship. Clumbmen bars, DG pipes, Rickman fairing, then I got an RZ 500. I was in my 20's then, now I'm 45, and 1 year ago I got a deal on an S2 350 Kawi, love that bike too, but it triggered the old 2 stroke in me, and since then I have picked up a 75 RD350 and an 82 RD350; now I want a Daytona rd400 to complete the collection. Damn I can't get enough of 2 strokes.

Just bored at work, and glad I found this to read. Happy 2 stroking fellows.

22nd Jan 2011, 10:37

I bought my 1975 RD 350 in 77 for 600.00 with 1200 miles on it. I am now 55 and still keep it running balls to the wall. It has 29,000 miles on it, and love it to death. Also it is just my weekend bike. And yes chambers,jetting, reeds, light head shave, K&Ns, new needle & jets, Wesco pistons (forged) and 12 volt VW coils.

21st Mar 2011, 19:53

I have had 4 RD400s, 2 RD250s, and an RZ350, from 1977 till today. Love those Yamaha 2 strokes. Way more fun than the 1200 Harley.

Now working on putting a 75 RD350 motor in a 1972 Yamaha FS1E; it's the same as a Yamaha G5 or G7S sport moped?? Yes, it will be nuts to ride at only 205 lbs.. It's ported and will have 32mm carbs and D&G pipes. Over 100 lbs lighter than the stock RD350... with tall gearing, who know how fast it will go..

1st Apr 2011, 17:32

I am no bike mechanic, but with the resources from the net from sites like 2strokeworld.com or usa2strokers.com, I had my bike jetted and tuned properly, as well as rebuilding my brakes and suspension.

Easy bikes to work on, but they need a little fiddling from time to time. A good electronic ignition is a great upgrade. On a budget, a Dyna S kit works great.

YZ125 reeds with 1 petal snapped off fit right in, and are even better than the Boysen reeds I had.

Add some SpecII pipes, which are affordable and very good.

DGs are a good pipe for the money.

Also, XS650 coils bolt right up and have a much hotter spark.

Some good USA parts sources...

economycycle.com (lots of RD parts)

hvccycle.com (lots of RD parts)

cedargrovemotors.com (bearings, seals and suspension)

vintagesmoke.com (for rear sets and Dyna kit)

mikesxs.com (some XS650 parts like coils bolt right in)

1st Apr 2011, 17:39

RD250 to RD350 conversion is a simple swap of heads and pistons.

Check 2strokeworld.com and usa2strokers.com for more info.

29th May 2011, 16:05

I purchased an RD400 back in 1986 for $25.00. Just about have it ready for the road, but issues with the ignition are holding me back. Got some great info from this site in regards to what will cure the problem. Will keep you informed as to how this helps.

12th Jul 2011, 21:57

I have 2 RD 400s, a '77 and '78. I have owned an RZ350, RZ500 and TZ750. If you have any issues with bikes that you own/are restoring, give me a shout. I either have the answer or know someone who does. kentech at windstream dot net.

29th Dec 2014, 20:58

She fouled plugs only when you lugged her around town. You had to keep the RPM over 2500k to prevent fouling. I went from an RD250 to an RD350. Never fouled a plug.

27th Jul 2015, 11:45


I have been to CT for quite some time for work.

Now back to India... I do have two RD350s. One recently bought for a cafe conversion.

Would be great to be in touch with you. I used to stay in Stamford.

My email - Dalvipravin81@gmail.com

4th Dec 2018, 21:06

Hi. I know this is an old post, but I'm buying one of these RD350 motor in FS1E Frames tomorrow. Just wondering if it was your bike? Not sure how often this conversion is done, but it's definitely cool. Hope you get this.

25th Sep 2021, 18:07

A switch to AC Delco coils is a must and brass swinging arm bushes.