Author Topic: Shift Shaft oil leak - RD400  (Read 242 times)

0 Members and 1 Guest are viewing this topic.

Offline hayduke

  • Plug Fouler
  • *
  • Posts: 25
    • View Profile
Shift Shaft oil leak - RD400
« on: May 05, 2021, 06:05:57 PM »
I'm assuming the drip comes from the shift shaft seal. I remember a post from Chuck, I believe, several years ago about installing a bronze bushing in the outer cover to help support the shaft. Does anybody know where the post may be or have any details on the task?


Offline rodneya

  • Fully Ported
  • *
  • Posts: 786
    • Canada
    • View Profile
Re: Shift Shaft oil leak - RD400
« Reply #1 on: May 05, 2021, 06:24:31 PM »
You should open that up and clean the area so that you can pinpoint the exact leak. It could be from the shift shaft seal, the neutral switch oring, counter shaft sprocket seal, shift fork shaft plugs, clutch rod seal, or if your sprocket nut is loose it can leak from the collar behind the sprocket.

Offline Organicjedi

  • Supporter
  • Stage 2
  • *
  • Posts: 424
    • View Profile
Re: Shift Shaft oil leak - RD400
« Reply #2 on: May 06, 2021, 09:22:57 AM »
I've chased a leak like this on a fresh build. I replaced my clutch pushrod seal and it seemed to lessen or maybe even get rid of the leak. It was late in the season when I changed it and I'll have to confirm once I start riding again for the year.

But yes the pushrod seal, neutral switch, and counter shaft seal are all likely culprits.

Offline NYSingh

  • Dialed In
  • **
  • Posts: 73
    • NYC
    • View Profile
Re: Shift Shaft oil leak - RD400
« Reply #3 on: May 06, 2021, 04:39:04 PM »
Had a drippy leak on that side because I buggered up the seal/cap (Part # 90338-22021-00) at the end of the shifter fork shafts when pushing them in, and fixed it by putting in a new one

I've seen Chuck solve this by filling up those 2 holes with sealant:

In any case, removing the side cover should reveal a trail of oil that should lead you to the culprit.
1976 RD400C (SpecII pipes, K&N Y-boot, Dave F Mod, Team Scream Racing Stage-1 Porting)
Moto Guzzi V7III

Offline RdsOnly

  • Dialed In
  • **
  • Posts: 79
    • View Profile
Re: Shift Shaft oil leak - RD400
« Reply #4 on: May 16, 2021, 12:43:09 AM »
RD400 has this issue I have seen- not so much in 350 rds. 400 Shaft stick out farther..
due to if the bike has gone down on the left side and the shifter got hit- ovals the aluminum in the case. Seal looks good- behind the seal is ova-led- hardened steel shaft hitting soft aluminum.

Machinist can bore and install oilite bronze insert to solve leak, anything other than that is a FIX- short term. On next engine out have it done- other wise place on center-stand to reduce leakage.
Side stand will leak bad.

« Last Edit: May 16, 2021, 12:47:15 AM by RdsOnly »