Hi,

I have a problem with my ΧΤ600E. The engine has very low miles(racing engine), recently rebuilt, 12.4:1 compression, forged piston, webcams 282o cam, ti retainers, uprated valve springs, new cam sprocket-chain.

Recently, it started making a ticking noise from the head, mainly in idle (1600-1800rpm). In higher revs, the noise from the exhaust doesn't allow me to hear for the ticking. It sound a bit louder than incorrectly setup valve clearances, but i checked and adjusted them, with no change.

The engines runs fine, idles very good(for this cam), no-oil burning and generally nothing strange than the ticking noise.
Inside the valve cover (seeing from the port for the adjusters), everything seems fine and neat.

I read about cam chain, but as i have changed it recently, together with the sprocket, i don't think it's the problem.

What else it could be?

Recently we had some time to work on this engine...

It has done some tough races during the season and in one of them an oil line leaked and it lost most of its oil, but it was rapidly stopped so no more harm has been done.

After the season, with no rebuilt, we had some testing and the problem that i describe above has started. (the rattling)

So today we removed the engine and disassembled it.

That's what the piston looked like...




It's only this side, at the opposite face there is some scars, but not serious. The barrel has some scratches but not as bad as the piston.

I have suspected the oil-pump, but i checked as the manual say, by removing the bolt at the oil filter housing, and oil come out right away, but not with much pressure. Also in the engine, if i open the drain plug some oil comes out, but as much as ~250ml.
Finally, as i found out today, on the head, under the camshaft, the gallery there had a lot of oil and the cam is in very good condition.
So i think that the pump is ok.

I also found some damage to the piston pin, at the point that is in the rod, and the piston has also some damage at the points where the pin is.

Why did this happen? How should i eliminate it?
I will probably go for an over-sized piston and barrel machining, but i would like to take an opinion on what's the problem.

I've got a piston/barrel like that!!! (see my thread in the archives).

It was a simple case of lack of oil.

Have you got the full spec of the engine?

I'm holding onto a XT600 hybrid lump that I'm going to graft into a fizzy or something stupid.

__________________
Tom
I'm a country member...

What you mean the full spec, it's as i have written in the first post.

I thought about the oil, but the facts i have written in the second post, i think that exclude the lack of oil.

Theres an internal net-oilfilter, you might wanna check that.

Take of the engineguard, and the plate arund the front of the frame, where you drain the oil from the chassis (in lack of better word)

Take of the oil line, and use a size 27 key (thats what it is here in Denmark europe, dont know your're messures) and screw out the filter. It's screwed in there real tight, something like above 100nm. Rock it, and put all ya' weight in it, and it will come of.


The filter shouldn't be clogged, mine has done 70k km and i dont think it has ever been cleaned, and there was next to nothing in it.

But its worth trying.

Sorry, i forgot to mention it...

The engine is not on a bike, it's on a small single seater car.
i use a custom oil tank (~3.5L capacity) with hi-pressure oil-lines and in-line oil cooler. So no in line oil filter.