1989 XT600 (kick start) timing question
 

I am getting a clicking sound from top end. Motor is new to me, its had a recent top end rebuild (piston, chain and clean up) before I bought it.
I checked the chain and it is on the 1st wear mark (new).
loosened and tighten decompress cable and no change to clicking.

Timing mark question.
When my rocker arms have a little movement they are at the mark with the little circle and line through it. Which is not TDC
When I turn the flywheel till the "T" the rockers have no movement but the piston is TDC (checked also with screw driver).
I am wondering if the clicking comes from the valves being maladjusted?
The book says the the rockers should have a little play at TDC

The bike runs strong now and idles smoothly, just worried about the top end noise.:eek3:

Am I thinking this through correctly?
Thanks
Greg

I know nothing of your particular bike, but on any four stroke there are in effect TWO TDC positions 360 degrees apart. On either compression stroke when both valves should be closed so tappet clearance can usually be detected. The other is at the end of the exhaust stroke, and by then the inlet valve may well be open as well. you will not have any play there. just make sure you are on the compression stroke when you are looking for tappet clearances.

Hope that helps.

These bikes do have some top end noise. It is important to verify your valve clearances are correct. Also, verify you have .5mm free play in your decompression cable. If there is NO play, you may be hearing noise from that. There is an in-line adjuster to set that free play.

For valve clearances you need the manual for your bike. Correct position for setting valves is TDC when both intake and exhaust valves are not depressed. You set the flywheel at the TDC mark, engine cold and adjust for the proper clearance. My 86 setting are: intake .0028-.0047 in. 3 thousandths nominal and exhaust .0047-.0067 in or 5 thousandths nominal.

After setting, recheck after tightening the lock nut. When tightening the lock nut, hold the adjuster still so it will not move. Feeler gauge should have a slight drag feel and not sloppy loose for a correct setting. You set both sets of valves at the same time, same timing mark TDC setting.

Hope this helps. Too loose or too tight is bad so check it.

Noise is top end, sounds like valves
flywheel has 3 marks: circle with line, H and T
TDC is at the "T", i can see this is the max height of piston
Both inlet and outlet were tight at T position. Adjusted them to spec with engine cold.
Same ticking

Decompress decmp cable only loosens the one exhaust valve correct? Would it be louder then perhaps on that side? Sounded the same to my ear on both sides.
Also decomp setting: if using my hand and pulling toward back of bike i should set for 5mm before the pressure begins? So this would be very immediate?
Thanks
Greg

Decompression cable is 1/2 mm not 5 mm free play. This is just to make sure the decompression lever in the rocker box is NOT engaged in the running condition. If it were too tight, the rocker arm of one exhaust valve, the right side, would be tapping against it making noise.

So you have set the valves? Did you have a slight drag on the feeler gauge? If it is too loose, will rattle.

If your decompression cable is too loose, you will not get the full effect of the decompression and starting will be harder to accomplish. Set correctly, the correct procedure is to depress kicker until it clicks, allow kicker to come to the top the kick fully and hard. Learning the starting procedure for your bike is the key. They are all a bit different.

Intake adjusted to .08 slight drag feeler gauge
exhaust adjusted to .14 slight drag feeler gauge
Both these measurements are in spec
sounded a little worse i think

Can I easily disconnect the decom cable to see if that helps?

Maybe take a bright flashlight a have a look inside the rocker cover just to see if any damage can be seen. You'd be looking for a worn cam or rockers that don't move as much as the others.Pay closer attention to the one by the decompression lever.

this is a video of problem -https://vimeo.com/76435964

When i open the caps (valve checks) i can see there is oil circulating.

otherwise runs good starts fairly easy as well.

Which type of feeler gauge are you using, a US Inches or a Metric? Sounds like too much gap... .003" or .005" intake or exhaust. .003 and .005 is inches or put another way 3 or 5 thousandths of an inch. By the clack sound, it sounds like 8 and 14 thousandths of an inch.

i'll give another check
When I started it made same sound. So before I made any adjustment. At that point the valves were tight with no room to get the smallest feeler in. After loosening valves to what I believe to be spec I have the same clicking.

That doesn't have the exact sound of loose valves, from what I could tell. To me it sounded like that decompressor hitting . Start the bike up again and feel the decomp lever to see if it is moving . Another thing to try is with one adjuster cap off, with it running take a oil squirt gun and quickly squirt a whole bunch of oil over the rockers and parts to see if things really change. It will make a bit of a mess but may tell you if it is an oil supply problem or if one particular rocker is doing it.
Just make sure you don't put the tip of the squirt gun inside and have it get pinched by the rocker.

After listening to it several more times, it kind of sounds like the left side is louder(as your sitting on the bike). By the tempo it definitely has the valve train speed and sound.

When you recheck clearances, grab each rocker a try to wiggle it, see if any have a bunch of side to side movement or feel different than the others.

This is interesting, please keep us in the loop. if you just cannot come up with anything, it is time to remove the rockerbox and have a good look at the cam and individual rocker arms. The rockerbox does NOT have a gasket, you just need some Yamabond #4 or similar to seal it back up. Valves need to be rechecked after reassembly. Take pics and post here.

This procedure can be done with the engine still in the frame but you will need to remove one bolt underneath the back side, top hangers as well as front bolts then the engine will tilt downwards allowing the rockerbox to be removed. There is at least one bolt inside the rear valve opening and one on the very top in the recess. You will need a 5mm hex socket. Seems like there may be a extra bolt somewhere starting with the '88 model. Not sure as I have an 86 and 84 model.

The valves were loose, I didn't adjust properly. I readjusted to spec but have same noise/clicking. It is perhaps less so but still there.

Question- when adjusting valves: I am turning flywheel ccw till reach "T" to TDC. Would i need to go another 360 deg if I'm not at correct spot of stroke? Another words every time the T shows on the flywheel is that the correct spot to adjust valves?

I'll take off the rocker head and post findings.

Do i need to drain oil?
recommended sealant other then yamabond:?
thanks
Greg

NO, you must be on the compression stroke. This is indicated by both intake and exhaust valves being closed. You align the T mark to make sure you are at the very top and the valves are at the very loosest spot for adjustment.

No you do not have to drain oil. Just make sure you have some sealer, like Yamabond #4 to reseal the rocker box. You put the sealer on both surfaces after a good cleaning to remove old sealer and any oil. Apply sealer and let air dry for 3 or 4 minutes to get tacky then assemble. Once assembled it is good to let sit for a few hours or a day to allow the sealant to dry and not leak.

The sound on your video does sound like loose settings. Just make sure you are at TDC on compression. TDC on exhaust stroke you will see exhaust valves close then intake open, just rotate to the next TDC. Looking at the stator, CCW is the correct direction to turn.

Thanks Steve
This video was after I readjusted, hard to tell if there was an improvement.
https://vimeo.com/76520601

Sounds louder on the right side. Did you grab ahold of the compression release lever on the rocker box to see if it was being tapped?

That one came through a little better on my laptop, It does sound like rockers, but real bad rockers. Rather tinny sounding though instead of a more knock. I imagine a real loose rockers would make such a racket. I didn't see the comp lever moving at all in that video so that may not be it. Definitely make sure your on the compression stroke when adjusting. If your at the wrong TDC, the intake valves can be checked and adjusted because they will be closed, but not the best way.
To verify your on the right TDC, look through one of the exhaust valve ports(those round caps in the valve cover). With a socket on the crank turn it CCW while watching both for the "T" and the exhaust rocker inside that port. If that rocker is down or moving as you near the "T", that is the wrong one. go one more revolution to "T". All your rockers should have a little play in them when you wiggle them with a finger. You are loosening the nut first on the rocker, then slowly turn the "bolt"(with the slot), when the feeler guage just drags but not stuck, hold the bolt still, while snugging the nut up.

Did you squirt any oil as it is running to see if things quiet down at all?

Thanks guys
The first time i adjusted I'm pretty sure I was on the wrong stroke. The second video was I think correct. So I had top end noise at 3 stages now.

!st without adjustment,
2nd which is the 1st video (1st attempted valve adjust)
3rd adjusted i hope correctly 2nd video

All 3 times have the same sound maybe different volume but not sure.

I started taking the rocker head off (bike has over torqued bolts and rounded heads all over.

One thing I noticed is the decompress lever looks knocked on the edge. Could be normal wear and tear or its getting beat up. Uploaded pictures
Flickr: gregcappello1's Photostream

rocker head is off
chain looks good, not loose
cam looks fine, no marks
valves all at same height, all look the same
plenty of oil up top

Rockers all look good, no obvious wear by sight
there is very little movement side to side but slightly more from decomp exhaust valve (not much difference really)

The only thing that is obvious to me is the decomp side exhaust valve, the tappet when compared to the other side would be turned out further making a loose valve.

I'll upload video in a bit of rockers

video P1060127 | Flickr - Photo Sharing!

The face of the right exhaust tappet looks worn. Everything else looks normal. Does the rocker arm appear to be straight? From the pics it could be bent a little. Still not sure where the noise is coming from. Is there wear marks on the rocker arm where the compression release arm touches when engaged?

My windows 8 pos computer wouldn't open the video but the decomp looks normal for wear from a 30 year old bike, with that amount of noise it really should be something obvious I would think. I can see the rocker faces and they look normal.

Their does not seem to be any high wear. when I put the decomprs lever back in, it lines up. Nothing indicating stress as well.
Rockers all move with same range, right exhaust moves with slightly less resistance. The valves, chain and cam all look good.

Try wiggling all the valves and springs themselves , just to see if anything seems loose. I'm kind of at a loss then. The noise couldn't be coming from down lower, it has to be up top.
Do you have an air hose? A person can put air pressure into the cylinder and see if any air comes hissing out a valve to find maybe a broken seat or bent valve, but I really don't think thats a high probability. But you never know, it did show up all of a sudden and after it was shut down, then started cold.

checked valves and springs and all were identical. Nothing looses
Trying shooting air in spark plug hole nothing unique.

I have kawabond, does anyone no if this is a good alternate to yamabond?
If its good it saves me a trip :)

I do not know about Kawabond. Is it a grey color? I suspect it is the same. Similar name, Hondabond is about the same etc... Permatex Motoseal grey is about the same, used it with success as well.

Everything is all back together and noise remains
Real pain in the a.. getting the rocker head off and again finding more over torqued bolts.

Found no obvious problems when head was off so I knew the noise would be back.
I even pulled out the decomp lever when it was running. Made a mess with oil but noise unchanged.
The sound is definitely top end, sounds strongly like tappet. When the valves have play at the compression stroke I can mimic the sound (basically) by tapping the rocker down.
Tomorrow just for a trial I will tighten valves up a bit to see if their are changes.
Thanks for all advice
Greg

I remember a post awhile back, maybe another forum. The guy did all you did and nothing. He finally pulled the head and found one of the valves was actually just touching the piston because the piston was a bit loose in the bore and rocked enough for the valve to touch it... He bored, fitted a new piston and all is well. You certainly should not run it "anyway". Pulling the head is only a bit harder than the rockerbox and you will need a new head gasket and other seals etc.

There was one also like steve said that the piston was just touching the head at the squishband and causing a knock. When the head was pulled you could see slight marks on the piston edge and head. It was barely shinny. I would maybe do like you said, tighten them up to .002" clearnance and see if any changes. There has to be just one stupid little thing doing this.

The top end was rebuilt (new piston) I would imagine not that many hours ago (2011) as the bike was not road legal. Now people sell for a reason so perhaps that was a problem. I will tighten up the clearance to see if their is any change.
Just sounds like tappets hitting but if my test at tight and loose shows no change then I'll have to take a look at the piston.
If it was a problem with the valve hitting the piston would it sound like loose valves? Also I would think the valve would of bent, maybe loss of compression? I just don't see signs of that.

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.

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

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.

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.

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.

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

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).

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

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

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.

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

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

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.

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

I have taken the lever out when it was running and had same noise.
Pulled the lever out of rocker head.
I'll loosen it up tomorrow and get a video of the actual start.
thanks i really appreciate the help

Two videos
> shows a cold start. After 45 seconds you can hear the clicking getting stronger. Its seems to get louder with tightening of decomp cable. XT 600 Top end noise - YouTube

> decompression cable: I start i think mid adjustment then tighten. Then I loosen up. https://vimeo.com/77238617

If i do need to take the head back off I will be looking at thread problems with the bolts. Can some one please give me advice on what you have done with over torqued head bolts

Also I have 2 frames, good one to be painted (if i can sort motor out) and one I'm using now (in video). This frame has a weld to keep right foot peg assembly on. It will prevent me from taking off RH cover. Very crappy sloppy weld. Until I switch to other frame I am stuck on that side. Goal was to rebuilt suspension etc 1st

Well that was some great videos and showed the difference with the decomp. It doesn't look like that is whats going on as long as it's loose enough. In the first video when you start it, I thought that was normal sounding, at least how the 2 of mine sound, you can here some noise but is mostly drowned out by the exhaust, however I think it had more to do with how the sound was being recorded because it was louder later on.
For the threads in the heads, if they are not stripped now, they should be fine, just try to find some longer bolts to grab more threads if possible and as long as the bolts don't bottom out. If the threads are coming out, then there are helicoil kits where you drill out the holes then rethread and insert a helicoil(red loctited) to restore the correct size threads.

Yes it sounds very well for the 1st 30 seconds. Perhaps I can only drive in 30 seconds intervals.
What I'm trying to figure is what the heat is doing. There is thermal expansion and there is thinner oil. Perhaps I shoot some heavy 80 weight oil in.
Man I really don't want to pull the head again and be back to square 1. I'll take another stare at the lifters. :offtopic:

Do you have 20W-30 in it now? that what I run, for under 45F I'll switch to 10w or 15w but mostly run the 20w.
I'll be willing to bet there is one rocker that is either a little loose on its shaft or sub rocker that is out of spec,
. Did you try the oil squirt gun and heavy oil, when the bike is running, unscrew one front cap at a time and squirt a bunch of oil over each rocker to see if the noise suddenly quiets or changes when the oil hit one. you would then know where it is coming. If nothing chages, then it has to be something deeper. Try to hit all the rocker pivots and where they contact the valves. Cam lobes also, I will make a mess, but may end the wondering.

I am running 10-40w its a 50/50 half synth

I think you are right. The exhaust right side rocker had less resistance then the other 3. There wasn't much difference in movement side to side between any of them. The exhaust right side rocker perhaps has to much play in it. I didn't measure it and regret that now. It just didn't seem to be an obvious problem and i was feeling it was a problem with the decompression cable.
Example: If i was to lift the rockers and let them fall, 3 of them had slight resistance to the fall. The right side exhaust would just fall.

To me at the time it seemed that wouldn't indicate a problem as when the motor was running that would be a non matter. Was i wrong.
I just don't know if i could be damaging the motor if I run it.

What you describe about the rockers not falling on their own(normal and good) and the one is looser could be what is the issue. If it was mine, I would just run it (as long as it wasn't annoying badly). The possibility of it being rocker related and not something more "serious" is so high that it's worth it to run and see if anything breaks or if it gets louder yet. I'd just keep an eye on the noise and pay attention to any changes. If something is going to fail it will do it fairly quick, otherwise not for a long time. Along the way maybe keep an eye out for a new rocker and shaft, if somewhere along the way the cover needs to come off, replace it then.

Thanks!!

tried shooting some oil in but it was just too messy. So oil is being pumped.
Feels like the the rocker is hard to adjust. Like it is missing some damping somewhere if that makes sense. This is the right exhaust.
I think since the rocker is perhaps looser that's the issue. As I said earlier, mimicking the sound by self tapping the rocker seems to copy the sound very closely.
I am going to ride it and I'll look at the rockers when I switch frames.
Thanks for all the help
greg

If that is what's doing it I can send you a good shaft and rocker setup. I have about 6-7 topends to choose from.

Hey JJrider thanks for the offer, if you can spare just let me know what you would need.
I ran it for about 30-40 minutes today, noise very consistent. No increase. Besides some oil leaking from some over torqued bolts and a carb stumble well it ran better then i thought it would.
I am going to start a new thread on carb stumble :(.

I have a rocker cover with several rockers and shafts still in it but the cam journals are shot. I'll clean it up and take a look at clearances , should have enough extras in there in case you need to change more than one. I'd say a few bucks more than shipping and it's yours. Where you located at? That may be the deciding factor whether it's worth it or not.

Here's some pics of that cover and rockers. After washing it all down in parts cleaner the rockers all moved with resistance and tight. The pads cleaned up pretty good, not the absolute best, but easily usable. The one by the bad journal I wouldn't use but the shaft and wave washer is good. I'll know more tomorrow night as far as the carb parts.

Update
over 400 miles and no changes. hard to put many hours as winter has been rough here.
Same sound when warm, has not increased. Have run for over an hour at a time with no issues. Burns no oil.
Still don't know how confident i should be on longer trips away from home.
Greg