First timer here...just got back from 360 mile adventure. Bike ran fine to destination but on return trip the power dropped of substantially and was surging abit. Now after every run oil drips from the drain tube in the air cleaner box. Also, on hot start ups there is a random rattle almost as though there is oil starvation. Bike has 19,000 miles on it. Hoping one of you veteran XT guys could point me in the right direction. Thanks for your time

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1990 XT600
Bone stock- removed spark arrestor
Dunlop 606 tires

While you are waiting for the experts on here to reply, you may find this website useful to understand what is going on:-

http://www.horizonsunlimited.com/hub...640#post139806
I am a bit of a neanderthal for bike engines so I am not trying to provide any advice but the experienced guys in here will do!!


I've had a lot of helpful advice from these threads - I guess you will get the same assistance - Good luck,

Dave

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Dave

The oil dripping from the air box is a bit of a worry as this can be caused by the presence of a lot of oil mist in the crankcase breather pipe or high pressure in the crankcase. What happens is much more oil than normal gets sent into the air box and then ends up dripping out of the box. Have a look at the air filter and inside the box and see if it has any oil contamination.

If it has and the cause is not because you've seriously overfilled the bike with oil, you may have a more serious problem.

One cause could be a blown head gasket that is allowing combustion gases to blow into the cam-chain tunnel, the other could result from a partial siezure that's allowing gas to now blow past the rings. Both problems mean the gas has to go somewhere, and that means up the crankcase breather pipe into the air box carring oil mist with it. Take the air filter out and start the bike up. If there's a load of mist (looks like blue fog/smoke) coming out of the air box, you've definately got a problem of this sort

Both problems would reduce the power.

Not sure of the cause of your rattling as you don't say wher it's coming from

Check your valve clearances first though just in case you have a tight valve.

Is the bike smoking from the exhaust at all? Try and get mate to follow you and see. Are you having to now top-up the oil frequently ?

Good luck!

Thanks for the help guys. Rickg, great info. I thought the same thing and checked the air cleaner first thing and it's dry.Haven't got around to running it without the air box cover yet as you suggested. The rattle I referred to sounded like bearing knock to me but it only happened once while it was hot. Haven't got a feel for the oil consumption yet as I don't have many miles on it since it started misbehaving. I've got to find a manual to get my valve clearance specs. Funny, when started cold it sounds and runs just like it used to. Exhaust note has good "pop" to it. My gut feel is that compression is good but i need to confirm it. I hear guys talk about the cam chain. Does there seem to be an average mileage on these engines when they need replacement?

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1990 XT600
Bone stock- removed spark arrestor
Dunlop 606 tires