xt600 cylinder head & cam worn
 

Hi to all (just joined 2day)
Help needed with 1985 xt600 C reg recently purchased bought it with a nasty top end noise (metallic rattle) have stripped the top off, the cam + journals are scored and dont look good so i think it needs another head / cam etc unless anyone can tell me otherwise ?
The question is the frame / engine nos. are 43F but the head are cylinder are 34L is this right or is it a problem or are the parts interchangeable?

forgot to say if anyones got a complete head ? let me know
thanks

heads up
 

Yes, the parts are interchangeable - see earlier posts of the intricacies of Yammie part numbering.

How badly scored are the bearing surfaces. They tend to look pretty bad before they are actually shot. Does the camshaft have play when installed? Bad camshaft is also usually a sign of bad or no lubrication, and then normally first the piston goes. You sure that is not the problem?

If they really are bad, you could get a machine shop replace the bearing surfaces in the head / cover with steel shells and use a replacement camshaft (second hand). Might have one lying around, but I'll only know in a week or two.

pics
 

Hi thanks for the reply i have just uploaded some pics to show the scoring dont know about the piston yet as i havent taken the head off yet.
As for the lubrication im with you i think it was lack of maintenance oil & filter were very dirty

Attachment 4039

Attachment 4040

Not new, but might still work ..
 

It does not look too bad, indeed some scoring but not over teh whole bearing surface. Should it be bombproof after repairs or can you take some slight chances? That is, you do not want to be stuck in the middle of Congo with a broken camshaft.

I'd first check piston / cilinder and cam chain - those are the parts that rattle if worn. I actually would not know what noise a camshaft would make.

I also notice an enormous amount of liquid gasket on the mating face cover / head. The 2 are supposed to be joined metal-to-metal with only a very small amount of liquid gasket. Reason is, the 'bearings' for the camshaft are drilled like that, so that state should be copied at reassembly.

Success!

Aukeboss when you say
"I also notice an enormous amount of liquid gasket on the mating face cover / head. The 2 are supposed to be joined metal-to-metal with only a very small amount of liquid gasket. Reason is, the 'bearings' for the camshaft are drilled like that, so that state should be copied at reassembly."

there is actually a gasket in amongst all that sealant ? but what you say does make sense

Engine is now stripped indeed the piston is quite badly scored and the cylinder bore has some wear so i think it will be a new piston and rebore also the cam chain adjuster is on full adjustment
Attachment 4052

Think i found what may of caused the bad lubrication some runny chewing gum like sticky substance in the bottom of the engine think it was maybe like some kind of leak stopper or something but it probably blocked it all up
Attachment 4053

also have tried searching earlier posts for the intrices of the engine numbering but no joy do you know would a 3AJ cylinder fit

thanks

Attachment 4054

Attachment 4055

dont think the pics came out in prev post

a gasket?!
 

There should definitely NOT be a gasket there, or you have a version from out of space. Just remove all the goo, and install camshaft in the head and the cover on the head. Camshaft should turn easily. Little test should confirm my statement. Might also be the cause of your lubrication problem: the gap between camshaft and bearing increased, increasing oil flow to the head and thus reducing oil flow to other parts.
Plus the white goo thing off course. I'd just take the whole engine apart now, since that hardly increases the cost, and you'll be able to clean everything thoroughly. You will of course see the gears which might also need replacement, etc.

The noises you heard were definitely piston / cilinder and / or cam chain. That's good news for the cam shaft and head!

3AJ cilinder fits on this engine. Yes, it will fit on the lower end, but will the head fit onto it? The 3AJ cilinder has 2 bolts at rear and front end of the cam chain tunnel, the earlier version has only one. I'd just do the rebore, more effective than installing a cilinder with unknown history etc.

new parts ?
 

ok so i have got a replacement top end from a 1984 TT600 ? the head is marked 1KJ its in perfect condition as is the cam result! the cylinder is marked 3AJ its aluminium with nikasil (are they all like this) its slightly worn and scored the piston is worse
I have tried the new head on the original cylinder 34L but it doesnt fit? the 2 bolts dont line up
is it worth replating and new piston the 3AJ cylinder or should i try and get a head to fit the 34L cylinder which is better?
thanks

xt600 camshaft bearing wear
 

Another possibility is machine the bearing bore and insert metal replacement journals .

In Germany is a company that will do the job for You, they use proper bearing journals coated with babbits metal .

Another solution to do it Yourself and use bronze journals. The journals used in this xt are porous, so they hold a mall amount of oil when engine is not running .

An excellent first post so, :welcome: to the HUBB.

I well recall being a tad surprised at the lack of bearing journals in the head of my TT600R when I took the head off a few years ago.

Bang on. :thumbup1:

Mezo.

After 5 years I think he got it fixed by now :innocent:


A simple TIG weld up of the journal and remachining of the bore works . For a mild worn journal a person can just face .005-.01" of the top face of the head (or cover , which ever side is worn worse ) and rebore the journals with no welding.
I'd be very Leary of those bushings sliding sideways or spinning and jamming with no locking notches like main crank bearings in auto motors.

Kawasaki also casts a little pocket in the middle of the bottom journals to hold oil for start-up till oil is fully circulating. A person can drill a few small dimples in the Yamaha journal that doesn't have any to do the same to help out.

I've tried TiG welding , however this was a disaster . Possibly due to the composition of the material or the oil soaked in the pores of the aluminium .

The danger of dislocating the journals is minimum, axially they are fixed by the camshaft, the pin stops rotation .

I'll post the results after the engine has run a considerable time .

Yes. I have wondered what happened to aukeboss; 2010 might be the last year that he posted here (and his blog shows that year as his last input).