pesky oil leak

[Mike 86 in San Dimas]

I replaced the o ring for starter. Eureka oil leaked stopped... for a couple of weeks. It's back. Its minor but I hate it. Replacing o ring is a snap and dont mind doing it again. Wondering if there are some words of wisdom to increase odds of a lasting fix.

BTW I replaced sprockets with 18/40 combo (new chain). Like it. The loss of get up and go is detectable but not extreme at all, but like getting that 6th gear on the freeway without buying a 2017 FJR. Knock it down a gear and your off. Literally only rode once at freeway speed. Satisfied.
Mike

[balky1]

The same O-ring is leaking again or?

[red]

I replaced the o ring for starter. Eureka oil leaked stopped... for a couple of weeks. It's back. Its minor but I hate it. Replacing o ring is a snap and dont mind doing it again. Wondering if there are some words of wisdom to increase odds of a lasting fix.
Mike

Mike,

More info, please . . . Was the O-ring the correct stock Yamaha Part Number item?  Was it very old stock?  Do you know why it failed to hold a seal?  Alternately, was the new O-ring the correct size, and the right thickness?  Was it intended for use with oil (as opposed to air or water seals)?

If what you have is the only repair part that you can get, there are two possibilities to make the new part work, anyway.  

One way is to use RTV (Room Temperature Vulcanizing) Sealant.  Run a small bead of sealant inside the O-ring groove in the metal, install the O-ring into the groove, and run a small bead of sealant on top of the O-ring.  Press the metal cover in place firmly, then remove the cover for a moment.  Wipe away any excess sealant that is inside the O-ring groove with toilet tissue.  That means any excess sealant on the cover, and on the casing, inside where the O-ring will be.  If you do not perform this step, you may find "strings" of cured sealant loose in the oil one day (not a good thing!).  Then install the cover plate normally.

Another way is to make a pencil (charcoal) rubbing of the O-ring groove, and cutting a very thin gasket to size.  Arty types can show you how to make a charcoal rubbing, if necessary.  Glue the paper rubbing to thin gasket material using Fas-Tac (or similar spray adhesive) and cut out the gasket with sharp scissors.  Set this thin gasket down flat into the groove, before you install the O-ring.  Then install the O-ring and cover normally.

[Pat Conlon]

Mike, I see (3) O rings, which one is leaking? My guess is that it's #2 the wet ring.

http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1986/FJ1200S/STARTING+MOTOR/parts.html

I see the motor O rings #2 (371-81847-20-00) are no longer available from Yamaha.

[Mike 86 in San Dimas]

Thanks for reply. Dont know why it  started to leak.  New starter a few years ago. Purchased o ring from RPM. It should be correct. It worked for about 1000 miles.  I may just try another. Leaks again i may try some RTV.

[racerrad8]

... Leaks again i may try some RTV.

NO...




We need to see if that is the source of the leak or if it is another place now. There are six sources of oil leakage on that side of the engine.

Randy - RPM

[FJmonkey]

Mike, Randy showed me where to look for different leaks when my '86 was incontinent. Bring it by my place and we can find the leak source. Incidentally, Randy thought my starter O-ring was the leaker (it may have been). So when I pulled it to put a new O-ring on I found the old one was twisted in the groove. Once out it would not un-twist, the heat and time had caused a permanent set. So it is possible to damage the O-ring during install.

[Mike 86 in San Dimas]

... Leaks again i may try some RTV.

NO...
We need to see if that is the source of the leak or if it is another place now. There are six sources of oil leakage on that side of the
Randy - RPM

I was kidding? Agreed.  need to double check where it leaking from. It could be different leak this time. Been too busy partying this week end.  Anniversary. Will probably leave as is until rally. If it stops i will check oil level.

[simi_ed]

<snip>
So when I pulled it to put a new O-ring on I found the old one was twisted in the groove. Once out it would not un-twist, the heat and time had caused a permanent set. So it is possible to damage the O-ring during install.

Mark & Mike; if the O-ring twisted during installation it needed a bit of lube going in.  Try either motor oil or some grease on the starter body & O-ring before reassembly.  That should do the trick.

Sorry if I'm pointing out the obvious ...
Ed

[FJmonkey]

I always lube seals before installing them. Being the second owner I don't know if the twisted O-ring was factory or PO.