hello everybody,
happy with my just bought 93 XT
but... there is oil leaking
It is the gasket at the bottom of the cylinder that is leaking
( not verry much but it does smell when the engine is hot, a mecanic told me that it is nothing to worry about,
I plan a trip to Mongolia(2 on the bike), so I expect rough roads, high temperatures....
Is this treally inocent?
How difficult it is to replace this gasket? ( I am waiting for a workshop manual(...thanks Dakota) is it possible to do for an amateur?
Thaks for your much appreciated replies
Pol

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The question is; Why has the base gasket blown?
Has the engine been rebuilt?
I believe the most common reason for a base gasket to blow is excessive crankcase pressure due to a build up of oil in the crankcase as the oil scavange fails. I think you should investigate you don't want a failed oil pump half way to Mongolia, or at all for that matter

I dont know if the engine was rebuild, there are clear signs of previous oil leak on the top of the crankcase.
how to investigate the problem?

again, is this possible by an amateur?(the download of the workshop manual is running(slow but running)...

sorry to be an amateur (mecanic)...

Pol

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Are you sure it's the base gasket?
It's quite common for oil to appear in this area, on the right side of the engine, due to stripped threads on the long clutch cover bolts that also hold the oil filter cover.

Its not a regular problem and it should be addressed.

When gaskets leaks, it needs investigating.

Maybe the barrel wasnt torqued down properly, maybe the gasket is badly seated etc.

Personally, I would strip it down and replace it.

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Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

personally I would clean it so it was completely dry. Then ride the bike to determine 'exactly' where the oil was coming from, and in what quantities.
Riding it may help determine the cause also. You may find you might want to strip it down for another reason, so why do the work twice ( blind).

just pulled the engine apart and the timing is all ok. what im feeling when turning the engine over at the crank is the starter motor turning, it doesnt dissengege with the engine. ive no picis in the clymer manual, does anyone know where/how the starter dissengages? ill post this as a seperate thread as well as ive changed the subject...

This thread is overly complicated now, i cant make head or tail of whats going on.

Thread hijacking is naughty Too many people on one thread. Maybe new threads should be started ??

Walkabout: You say your camshaft isnt turning when you turn the crank by hand ?

You have probably let the chain slip off the lower gear. Do not try and kick the bike again. I just hope you havnt jammed the chain in the gear or it will shear off the teeth requiring a new crank

You need to grab hold on the cam chain and make sure it doesnt spin on the crank.

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Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

Well, I have the timing cam in bits again and the timing chain is definitely not aligned with its driving sprocket at the bottom.
I 've been "fishing" around to try to get the timing chain back onto the driving sprocket at the bottom. Looking down the timing chain tunnel with a bright light it is clearly off the sprocket at the front and loose there, but it is a bit tight at the back - could be jammed between the rear chain guide and whatever.

I will carry on doing a bit more "fishing" but it is possible that this is not going to work out. As Auke says, the next thing will be to take off the left hand crank cover, although I have considered stripping down the engine again to get at the timing chain from above (any comments on that approach??!!)

Some questions arise:

1. It is not clear to me what is behind the left hand cover - as ever the manual is a tad vague - will I get directly to the timing chain and its driving sprocket once the cover is off or are there any other things in there to be removed once the cover is off?

2. Do I have to drain the oil to take off the left crankcase cover? (there is an oil pipe from the tank at the top rear of the cover and it is a bit flexible with an amount of flexy hose back to the oil storage tank (so it looks like it can "stretch" a bit)

Bear with me, I've not done this before either!!

While fishing, as described above, the timing chain looks OK and I have turned the crank with the wrench and the sprocket does not appear to be damaged - no teeth missing etc etc. ( it is easily seen with said bright light, just not so easy to reach out and touch!!)

Dave

ps I would really like to get this bike back on the road before the summer is over!

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Dave

............. to my last post, that there is nothing wrong with the timing chain either, not obviously anyway - it turns quite easily over its full length(feeding it through my fingers as the crank is not turning it) so I have looked at all of it and there are no teeth missing, broken or showing any other form of damage - it just will not move across onto the driving sprocket at the back - near the guide in fact. I've tried to use a long-handled screwdriver to move it over but that has not worked.


So, what is behind that left hand cover???

Dave

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Dave

Under the left cover is the alternator / generator / rotor or whatever you want to call it.

Its a bloody nightmare to remove but i think (if i can remember correctly) that the chain gear is behind the rotor.

Take the cover off, its a simple and yes, you need to drain the oil as its wet in there.

With just the cover off you might be able to get the chain back on without removing the rotor.

If you have to get the rotor off then then you need a special tool which is £180 from yamaha or you can make one yourself.

I hope you dont need to remove the rotor, its a BITCH job without the yamaha tool.

__________________
Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.