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Did I install my rear main seal too deep??
Posted: Fri Oct 21, 2022 4:55 am
by CHEWY1219
So I replaced my RMS in my 76 R75/7 with the cycle works tool. BUT I didn’t use the washers under the bolts...careless oversight. The RMS is seated a mm or so under the lip of the case and not flush. Will this leak? Should I pull the seal out and start over? Please advise. I already have the flywheel back on and the clutch.....
Re: Did I install my rear main seal too deep??
Posted: Fri Oct 21, 2022 9:35 am
by gspd
The RMOS should be flush with the case...AND bone dry, with the flywheel flange perfectly clean and dry.
One mm further in should be OK, but I doubt anybody's ever (intentionally) tried that.
If you didn't block the crank, be sure you can turn the flywheel before you put the tranny back in.
You could always put just the carbs back on and run it a bit BEFORE installing the transmission to see if it leaks.
Re: Did I install my rear main seal too deep??
Posted: Tue Oct 25, 2022 3:27 pm
by CHEWY1219
UPDATE....yes, 1mm is enough to make the RMS leak, and quite substantially. Tore back down, installed another seal with the tool from Boxer2Valve, buttoned back up and she is now as intended:)
Re: Did I install my rear main seal too deep??
Posted: Wed Oct 26, 2022 5:21 am
by SteveD
CHEWY1219 wrote: ↑Tue Oct 25, 2022 3:27 pm
UPDATE....yes, 1mm is enough to make the RMS leak, and quite substantially. Tore back down, installed another seal with the tool from Boxer2Valve, buttoned back up and she is now as intended:)
Good feedback...thanks.
Re: Did I install my rear main seal too deep??
Posted: Sat Oct 29, 2022 8:22 pm
by Rob
gspd wrote: ↑Fri Oct 21, 2022 9:35 am
The RMOS should be flush with the case...AND bone dry, with the flywheel flange perfectly clean and dry.
One mm further in should be OK, but I doubt anybody's ever (intentionally) tried that.
If you didn't block the crank, be sure you can turn the flywheel before you put the tranny back in.
You could always put just the carbs back on and run it a bit BEFORE installing the transmission to see if it leaks.
Excellent stuff, gspd, as always! I'm glad I knew about that before my first RMS replacement!
Re: Did I install my rear main seal too deep??
Posted: Tue Nov 01, 2022 2:42 am
by ME 109
gspd wrote: ↑Fri Oct 21, 2022 9:35 am
You could always put just the carbs back on and run it a bit BEFORE installing the transmission to see if it leaks.
That was your advice to me years ago when I couldn't find a leak. Turned out to be a small crack in the oil pump cover bolt hole.
Started the bike with no clutch in the way and there was the leak, saw it through the spinning holes of the clutch carrier. Bingo.