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-   -   burning oil. any tests to see where its from? (http://www.horizonsunlimited.com/hubb/yamaha-tech/burning-oil-any-tests-see-51652)

bobthebiker 22 Jul 2010 19:57

burning oil. any tests to see where its from?
I just noticed earlier today on my XT that it seems to be burning a little oil. I'm not really sure how much per X amount of miles since its not road legal right now.

I notice on startup it pushes out a little smoke, which clears prety quick, which makes me suspect valve guides are worn, is there any easy way to test this?

YamaHead 22 Jul 2010 21:30

This is the Exact reason I've got my XT6 SuMo torn down right now.....
Worn valve guides/seals :thumbdown:

Watch the state of your spark plug.....& keep an eye on the exhaust tip for (oily buildup).

*Touring Ted* 22 Jul 2010 22:19

The smoke on warm up IS the test !!!!

It failed .. Valve guides.

bobthebiker 22 Jul 2010 22:50

damnation. well, at least its not SUPER hard to replace those. I need to get the valve guides and I'll eventually get my lazy self to replacing them.

oothef 22 Jul 2010 23:30

Burning oil on start up or on over-run (closed throttle) oil's finding its way past the valve stems/seals.
Burning oil on the power its finding its way past the rings/bore

bobthebiker 23 Jul 2010 00:10

for me, its startup/closed throttle, so sounds like guides/guide seals are the issue.

oothef 23 Jul 2010 01:12

I wouldn't worry too much, you're aware of it and continue to monitor its progress while checking around for solutions. I think these days you can get guide liners but modern techs left me trailing.

bobthebiker 23 Jul 2010 02:19

well, it doesnt seem too bad, I mean I'm not the new mosquito control guy with my bike, so its not a major issue. I'll just keep an eye on the oil and ride it easy until I get it fixed, no biggie.

bruken 23 Jul 2010 10:58

While you have it apart check the tolerances of the valve stems themselves. Changing the seals may only be half the problem. If the valve is good, do not forget to de-burr them where the collets fit or you may damage the new seals when re-inserting the valves.

oothef 24 Jul 2010 00:33

Sound advice, the system I (half) heard about was (I think) reaming the original guides out, press fitting a "liner" this is then peened to size by driving graded ball bearings through the liner to achieve a very close tolerance to the valve stem (better heat transfer/seal and wear) this is supposed to give a better performing valve guide than O.E. Talk to engine/engineering shops and blame me if they look at you slack jawed or laugh outright.
Its stuff like this that makes me appreciate two-strokes and beer

bobthebiker 24 Jul 2010 03:21


Originally Posted by oothef (Post 298428)
Its stuff like this that makes me appreciate two-strokes and beer

ugh, I've dealt with two strokes, NEVER again unless its a chainsaw or weedwhip. EVER. in bikes, NO. they were awesome lawnboys back in the day.

I'm thinking I may just buy another head, and swap it out until I get the time/money to rebuild mine if I have to.

bobthebiker 10 Aug 2010 18:50

well, I found out why it was burning oil now. engine is mechanically FINE. I fuel up at home from fuel cans, and somehow I'd managed to get about a quart of motor oil in the fuel can. damned if I know how, but I have fresh fuel in it now, and checking my oil level, its right where it should be, no blowing smoke, no troubles.

geoffshing 10 Aug 2010 19:04

Good on you!

Me and a buddy were riding and his engine spluttered to a stop in Portugal. After lot's of scratching of heads and a trip to the local bike shop it with an idea of blown seals or busted engne they figured out he'd filled it with DIESEL..! LOL!!

He said his problem was a 'Loose Nut'........ the loose nut behind the handlebars! LOL!! :stupid:

Again, good on you for letting us know..! Safe riding.

oothef 10 Aug 2010 19:20

It's probably an unconscious craving for two strokes......
Once spent a morning trying to start a friends chainsaw, took the head off and smelled diesel........... There's one born every minute is a conservative estimate.

bobthebiker 10 Aug 2010 19:27

This is true. in my case, I"m just relieved I dont need to rebuild my head, or engine. she's a fine steed, I'd hate to have to tear her down.

I know someone else that put diesel in their bike. then tried figuring out for 6 hours why it wouldnt run.

good news is, this allows me to mess with the new exhaust system I'm fabbing up for my bike for the sake of DIFFERENT.

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