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-   -   1989 XT600 (kick start) timing question (https://www.horizonsunlimited.com/hubb/yamaha-tech/1989-xt600-kick-start-timing-72612)

jjrider 17 Oct 2013 02:32

The one I'm talking about the piston was hitting the head itself not the valves so it wouldn't effect compression. But as you said it sounds so much like tappets ticking and most of these others are more of a knock. Just strange.

steveloomis 17 Oct 2013 03:13

I stand corrected, the piston did hit the head, memory is weak.....

ajax 17 Oct 2013 03:14

yes it sounds like tappets, if i get a chance i'll try to get a scope to listen with. Perhaps I might be able to hear a difference from a location.
I will need all new bolts at this point and will have to tap the threads if I take the head off. Right now no leaks.
If its from the piston wouldn't it sound more like slap? Sounds too tinny and high (top) then piston slap. Clicking is in sync with throttle response.

jjrider 17 Oct 2013 03:53

many piston related noises sound like a rattle paint can, when you shake it and that marble rattles, only a bit deeper. Your motor doesn't really sound like that. Some things do surprise a person as to where it sound like it is from and what it sounds like. I feel this noise is related to tappets and wonder just what was done when it was rebuilt and why it was.
There are reports of many of these motors making these loud rattles from new and ran as long and as good as any, often the noise could never be traced down so it was just ran, and ran, and ran.

To bad your not near me, I have several complete rocker covers and it would be interesting to swap one out temporarily just to see what happens.

ajax 17 Oct 2013 14:43

3 Attachment(s)
Attachment 10813

Attachment 10814

Attachment 10815


This is original piston and jug
owner said jug was over torqued and head leaked oil. Don't know if it was a head gasket as well.

steveloomis 17 Oct 2013 15:01

So the pics are the previous piston and cylinder, not your current one?

jjrider 17 Oct 2013 15:10

It's weird why he wouldn't have just bored and honed that one, put inserts to fix the threads, new gaskets and re-use it.
Now the one question is what size bore is in the motor now? that is how that one piston started hitting the head, bored over a couple mm and then it could hit (IIRC).

xtrock 17 Oct 2013 15:36

Wiseco Cylinder Sleeve 3191FA | eBay

ajax 17 Oct 2013 16:42

Yes that was the old piston
New piston box, I would imagine it was the replacement is 4797M09700 Product Detail Information - Wiseco Piston Inc.

ajax 17 Oct 2013 21:47

another video
tightened valves to almost no clearance (took to no clearance than backed it a bit)
Noticed: >starts right up

>seems quiet for about 20 seconds then increases noise. WHY? happened to fast to get on video, then when warm its noisy

>noise

Really hard to tell where it is loudest, tried using a large screw driver to listen. Actually worked well but hard to be convinced.
If taking a guess I would say right side exhaust, but I'm not that confident

Tried to make video detailed. Oil was from opening valve check.
https://vimeo.com/77166755

xtrock 17 Oct 2013 21:53

How is the camshaft and rockerarms? If you adjust them and they are worn you never get the right gap, sound to me like sound is from valves.

ajax 17 Oct 2013 23:05

back a few post there is a video that shows rocker head. Cams look good no marks. Intakes move in sync as do exhaust.

xtrock 18 Oct 2013 00:52

Oh there is so many things you cant know just by looking at the items..Everything have to be measured, valves, angles on the valves, seat, springs, camshaft, rocker arms inside for clearence to shaft etc. If it was quiet in the beginning it was because it was cold, when it got heat gaps changed.

This is how it should be http://www.youtube.com/watch?v=bvhxxWERQic

http://www.youtube.com/watch?v=300-4iQQTKo

Bonus video ;) http://www.youtube.com/watch?v=anj9AkoTSyE

jjrider 18 Oct 2013 03:05

In your video the decompression lever is moving, that is where the noise is from this time. It should not be doing that , setup right it needs .5mm movement of the lever before touching the rocker. Yours is running right on it at all times. Try loosening the cable that goes down to the kicker. The adjuster is about in the middle of the cable.

ajax 18 Oct 2013 03:14

cute bonus video, give her a kick start one
Yes I know it doesn't sound correct:thumbup1:

I was worried that it might not be top end, even though it sounded like valves. I just couldn't detect an obvious problem.

When cold it sounds much better for a brief time (>30 seconds), Then tapping increases.
The noise seems to be the same regardless of valve adjustment though. As the tapping probably masks smaller sounds.
Wondering if their is enough evidence to look more carefully at rocker head.
What happens when it heats up seems to make the problem. What does heat do to the valves or rockers?
Thanks


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