Topic: RD350 Crankshaft Seals

[bill440cars]

       I know, It's not a Honda. At least it's a Japanese model. Anyway I need to replace the crank seals
  and I'd like to know if anyone else has done this already because I need to know if I can do it by
  removing the side covers and components to replace the seals or do I have to remove the engine and
  split the case? I'm hoping that I can just remove everything off of the crankshaft, pop the seal out,
  install new ones and put it back together. Any input would be appreciated. I got this 73' Yamaha
  RD350 for less than $100. It needs the seals replaced, some carburetor work & front brakes (Caliper &
  master cylinder) rebuilt. Pretty good shape otherwise. I remember these as being pretty good
  screamers when they came out. It'll be more to play around with than anything else. Of course, it may
  end up being sold for "CB" money. Later on, Bill

[Dennis]

       I know, It's not a Honda. At least it's a Japanese model. Anyway I need to replace the crank seals
  and I'd like to know if anyone else has done this already because I need to know if I can do it by
  removing the side covers and components to replace the seals or do I have to remove the engine and
  split the case? I'm hoping that I can just remove everything off of the crankshaft, pop the seal out,
  install new ones and put it back together. Any input would be appreciated. I got this 73' Yamaha
  RD350 for less than $100. It needs the seals replaced, some carburetor work & front brakes (Caliper &
  master cylinder) rebuilt. Pretty good shape otherwise. I remember these as being pretty good
  screamers when they came out. It'll be more to play around with than anything else. Of course, it may
  end up being sold for "CB" money. Later on, Bill

"I'm hoping that I can just remove everything off of the crankshaft, pop the seal out,
  install new ones and put it back together."

Sorry Bill, you can't do it that way. The Yammie crank seals have a raised ridge around the outside. Two strokes are very sensitive to any seal leakage so it should be done correctly. You need to remove the engine from the frame and split the cases. You do not necessarily need to remove the top end but it would probably be a good idea since you don't know what's inside.
Check out "Smoke on the Water". Bunch of stroker nuts there who favor RD's. (Haven't been there for a while, but they know me well.)
I have all the RD books (and a '73 RD as well). No they are not digital so I can't send you one, but I'll help you where I can.
First tip, buy OE seals - made in Japan, NOT India!!

[bill440cars]

Dennis,
              I've been into motorcycle engine before but, I gotta ask, when I start back to put it back together, is it going to be a pain keeping everything lined up to put the case halves back together?
I know that some engines go together quite well and some seem like you need four hands to do the same job. What do you think?

[Dennis]

Assembling the RD engine should not be too bad. You might only feel like you need 3 hands. 

Let me know what information you will need.

[Objectionableone]

All true.  You can pick up more info at www.USA2strokers.com as well 

[bill440cars]

Thanks Objectionableone, 
                                  There is quite alot of info on that site. I believe I'll be using it to help get my 
    RD350 back up to snuff and maybe a few mods while I'm at it. It is stock now but, I want to improve
    on it in some areas. Thanks again for the info. Later on, Bill