Valve clearance adjusted but now noise

I got the most clearance when measuring in the position described by the manual, that is piston at TDC. Same as you describe. So clearance should be sufficient as long as you have the specified clearance in the correct position. Also, on my 650, I am positive that clearance grows as the engine warms because it ran much better warm than cold.

If the engine gets louder and idles worse as it heats, it could be that it is overheating for some reason. Or perhaps a coil is breaking up when hot, giving a weaker spark. When it didn't want to pull at low rpm, did you try to ad a little bit of choke to see if it made things better or worse? Sorry, just throwing out speculations as I do not have anything firm to suggest.

faffi wrote: I have 6 valves between 0.15 and 0.20 mm and one between 0.20 and 0.25 and one between 0.10 and 0.15 and the head is silent.

Faffi, should your clearances be the same specs as mine. .08mm-.18mm? Should I loosen ones up that are at .08mm? I always thought that when the bike heats up the clearances get tighter.

Thanks

Whether they tighten up or get looser is hard to say and may vary from one engine to another, but before I adjusted mine I had two valves with less than zero clearance and two with next to zero and it didn't pull at all under 3000 rpm when cold. Once warm it went fine. After adjusting the valves, it now runs fine also cold. I tried to get every clearance between 0.15 and 0.20, but I must have mixed up a pair of valves with which had less than 0 in clearance plus I didn't measure all valves in the prescribed position, hence one roomy and one tighter than I wanted. But it wasn't enough out that I were willing to remove the camshafts again

Man, I write too much.

Well, point is if I had shim over buckets like you, I'd fit a shim one size smaller to get it to the roomier end of the specifications. But it would surprise me if that valve is the culprit of your issues.

faffi wrote: if I had shim over buckets like you, I'd fit a shim one size smaller to get it to the roomier end of the specifications. But it would surprise me if that valve is the culprit of your issues.

Faffi, I have shim under buckets. I just went through all the valves. What I found was tight spots in the cam. If I took a measurement right at TDC some of the measurements would be at .10mm, but if I turned the cam a little more it would go tighter than .05mm. So I made my measurements from the tightest spot on the cam lobe, and adjusted to get at least .08mm at that tight area.

The bike started up very smooth, but still with the tick. The bike had a lot more power, but as the bike got warmer the ticking got louder, it also seemed like some of the ticking came in intervals such as it was running with the cam chain. I tried tightening up the cam chain, and loosening it up but no change.

Is it possible that my cams are worn?

Sorry, I had it in my head you had a 1000, but I now see you have a 750. My bad.

That it gets louder as it warms is consistent with my findings that clearances increase slightly as it heats up. The clearances you run, even if they are 5/100 too roomy, shouldn't cause a loud head in my experience.

If your cam lobes and bearing surfaces looks OK, chances are that they are just that. You could have excessive clearance in the camshaft journals, making the cam sort of wobble in their bores. The only way to know is to use some special "plastelina" - mallable rubber strips placed between the cam and bearings before torquing everything up. You then remove the cam again and measure the width of the rubber strips to determine clearances. Still, it would surprise me if that's the case.

It is extremely hard to diagnose a sound via text, however, and even if I heard it I may not have had the correct answer for you. I think the best thing you can do is to let a mechanic experienced with these engines listen to it. I would also suggest you sync the carbs when the engine is hot enough to run erratically and see what's happening.

Oh, one more thing; are you 100% sure about the camshaft timing, ignition timing, spark plug heat range and -condition?

okay, I'm thinking the clearances are too big. I measured from the tightest spot on the cam lobe and tried to get it to .08. I just talked to a friend that raced KZ1000 and he said he would go about .03mm from the tight spot and .05mm on the exhaust at the tight spot.

What does anyone have to say about that? :dry:

Faffi, The cam chain is timed good, I'm certain of that, I did it tooooo many times. I'm sure the ignition timing is good unless it changed as I re-tightened the cam chain, but I tighten it to sound so it should be the same. I use the plugs that are recommended for my model, and they all look good.


I started it up today and found once warm, and after the choke was turned off it sounded nice and smooth (almost like a kitten purring). Then as it got warmer I heard more ticking, and when it got even warmer/hot it sounded rough (louder ticking and primary chain slapping around). Of course I did have a fan on it as well. I synced the carbs while it was sounding rough and it toned it down, but still hard on the ear.

"okay, I'm thinking the clearances are too big. I measured from the tightest spot on the cam lobe and tried to get it to .08. I just talked to a friend that raced KZ1000 and he said he would go about .03mm from the tight spot and .05mm on the exhaust at the tight spot.

What does anyone have to say about that? :dry: "


I think that .03mm-.05mm would be to tight. Fine maybe? If your racing, and are doing adjustments, repairs, etc constantly. But I would be the .05mm and not the .03, dam thats tight dude.
The .08 should be OK, and if the cams are not walking around, do to worn journals or bearings. Can you listen for the noise and pin down where, which lifter it is? Stethoscope, or a piece of hose held up to your ear, not in it, will help.

Hey Motor Head, do you think .08 at the most is what I should aim for at the tight areas. Because for example, I had a clearance of .10 at TDC on exhaust #1. When I rotated the cam a little more it was tighter than .05mm. So I went down a full .05 shim, and it brought the tight spot to .08. I figure that would be good, but I think I have some that are sitting at about .10-.12mm at the tight area.

Thanks

From what you have been describing, it sounds as though as you rotate the camshaft checking clearance, one of the other lobes is pushing against the cam, causing it to rock. putting more pressure downward on your feeler. Possibly a cam journal out of round. Since the compression and then combustion/ power cycles are on each side of TDC, looking at the Min/ Tight spot on either side is a good Idea. But If things are right it shouldn't change the setting.

bobski911 wrote: ...placing the feeler gauge between lobe and bucket just before its pointing directly away from the bucket. Then I slowly turn the cam. There is a certain point that it starts to tighten on the .08mm. I back the .08mm feeler out, turn the cam a little more and the .08 wont fit. If I turn the the cam a little more the .08 will start to fit again. Is this right?...

Imo, YES, use the minimum gap available as the measured clearance.

Good Fortune!

Have you ruled out the copper crush gaskets on the exhaust as mentioned earlier? Sometimes they will leak a little and it sounds like a tick. The way to check is start her up cold and run your hands around where the exhaust meets the head, if it is leaking you will feel the air, just do it fast before the pipe heats up. I have had to tighten exhaust bolts with motor running to get the gaskets crushed completely to get rid of leak (tick)