Sump filter was nasty!

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Nov 5, 2008
I removed the sump filter and the screen/gauze was full of crap. The entire screen was plugged. It also drained about 200-300cc's of oil out that hole. I cleaned the screen with carb cleaner and then soaked it in gas for a while until it was clean and I could see through it. I'm guessing it hasn't been removed in a longggggggggggggg time. I ran a magnet over the blob of junk and nothing metal stuck to it so that was a relief.
Maybe I should have a look at mine. I have not taken it out in 7 years. Only did so when I first got the bike. They only stop small boulders and I change oil very regularly.
The manual I have says it needs a cleaning every 2500 miles. But I might just do it once a year as the bike most likey won't see 2500 a year.
What's the deal behind the oil pressure relief valve? I found it looking over the fiche's on OldBritt's. Is this something that needs attention like the sump screen?
I was looking at OldBritts for the oil seal on the inner primary at the drive chain and only see a felt washer. Is that all that keeps the oil from leaking out of the primary all over the chain?
The felt seal works, is your crankseal leaking as this will pressurise the primary and the felt won;t work under pressure.
That felt gasket is for keeping dirt out of the primary. If you are leaking oil from it you have way too much oil in the primary.
I wonder if the primary line back to the engine or tank is plugged up. Some day's it leaks and some it doesn't. But it all runs down the backside of the inner primary cover by the drive chain. Does the engine feed the primary with oil and then the oil return to the tank or what? I will pull the cover again and check it out.
chopped850 said:
Does the engine feed the primary with oil and then the oil return to the tank or what?

The primary oil should be completely separate from the engine oil, as there's a crankshaft oil seal behind the alternator.
If that seal is leaking, then engine oil will find its way into the primary case.

Do you have the workshop manual for your bike? It's a must have.
Jim I have a manual and LAB I will check that seal out. I'm thinking about a harley's oil system where the primary is fed from the oil pump and then back.
The primary oil is strictly static. Takes a very small amount. I don't recall how much, I run a belt. As for the crankshaft seal, most leak. Not because of the seal itself, but because of the crankcase pressure. The fix is to install a check valve in the breather line. For $16 you can get the Yamaha XS 650 PCV valve and be done with crankshaft seal problems.
chopped 850

Your oil leak is likely coming from the chain oiler which is the oil tank vent. It comes off the top of the oil tank down over the chain behind the primary case so it can breathe it's foulness onto the chain for lube.
Primary case is self-contained, and holds 7 oz of oil (200cc). this is just enough for the primary chain to pick up a little as it runs around the clutch drum, but not so much that the clutch is bathed in oil.

Oil leaking seemingly from the drive sprocket area can be:
a) too much oil in the primary case
b) oil leaking from the transmission
c) oil leaking from the chain oiler - a sort of vent tube coming off the back of the oil tank, which is best capped off so it doesn't leak, IMO.

I put ATF in the primary case. This way you can tell if the primary is leaking (red spots under the bike) or if the main crank seal is leaking into the primary (red primary oil turns brown)
Thanks for the suggestions as I will look at all of them. Remember this is a chopper and not a stock bike in anyway. I didn't overfill the primary and the trans is not leaking as I have 80wt in there and the leaky oil is too thin. I will dig into it tomorrow and let you all know what I find.
Well I took it for a ride today and it again shut off after a few miles. Once the bike cooled down it was back to normal running with no issues. So something in the electrical system is getting too hot and shuttin off the bike. After this happens the head light is really dim until the bike cools off. So what would get hot like that and keep the battery from charging or continuing it's normal cycle? Is the rectifier, black box, or zener going south?
On standard commandos, the zener diode is mounted to the right Z-bracket, which acts as a ground and a heat sink. On Triumphs, the zener diode mounted in a special heat sink mounted right under the headlight.

Triumph heat sink looks like this:
Sump filter was nasty!

Sounds like whatever your zener is mounted to is not dispersing the heat quickly enough.
It's mounted to the top engine frame mount so it sit's above the engine and under the tank. If that is the problem then I will move it to sit under the headlight.
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