KZ1000 B3

Having a bit of trouble with the idle, either 2000 revs or will sit at 1000 and gradually die, we have done everything you can think of, its got batter since we checked the timing but not brilliant, finally did a compression test today and all pot are 85 - 90 ish getting to the top reading after a few turns, we put some oil in pot no 1 and it jumped straight to 100 in 2 compresses (turns ) no thje question is, given that i rebuilt the head, lapped valves, had a kwak dealer do the shims so valves should be perfect, the bike was running fine before the head rebuild, i did take off the barrels to have them bead blasted so dekoked the pistons, i just wondering if cleaning out the grooves where the rings sit may have caused rings that were ok before cleaning to be loose and worn now they dont have a bed of carbon to sit on in the grooves of the piston
would people agree it probably need a new set of rings, the bike has done 25,000 miles and the original honing marks are still just about visible in the barrels so i dont think they barrels are worn, any advice please before i spend £160 in 4 sets of rings, thanks

Ps. Its not smoking from the exhaust

woodsy wrote: Having a bit of trouble with the idle, either 2000 revs or will sit at 1000 and gradually die, we have done everything you can think of, its got batter since we checked the timing but not brilliant, finally did a compression test today and all pot are 85 - 90 ish getting to the top reading after a few turns, we put some oil in pot no 1 and it jumped straight to 100 in 2 compresses (turns ) no thje question is, given that i rebuilt the head, lapped valves, had a kwak dealer do the shims so valves should be perfect, the bike was running fine before the head rebuild, i did take off the barrels to have them bead blasted so dekoked the pistons, i just wondering if cleaning out the grooves where the rings sit may have caused rings that were ok before cleaning to be loose and worn now they dont have a bed of carbon to sit on in the grooves of the piston
would people agree it probably need a new set of rings, the bike has done 25,000 miles and the original honing marks are still just about visible in the barrels so i dont think they barrels are worn, any advice please before i spend £160 in 4 sets of rings, thanks

Could result from air leak at carb holders, and/or dirty pilot circuits, and/or carbs out of sync or mal-adjusted pilot screws, and/or insufficient (too tight) valve clearances (would check'em again anyhow to confirm being within specs), and/or hanging timing advancer (lube weight arm pivots via access through the timing window).

Good Fortune!

manifolds were leaking, that was sorted, pilots sorted earlier, put new float valves and needles in, had car oil in , changed to bike oil, carbs have been synced, advance and retard lubed and working fine

Just took it for a blast this evening, idle is perfect on side stand and dies off when you lift the bike upright, so thinking float heights possible, if its rings they're gonna have to wait for winter

going for a 500 mile road trip this weekend so if anything is gonna break it will lol

woodsy wrote: ....................... idle is perfect on side stand and dies off when you lift the bike upright, so thinking float heights possible

You should do the clear tube test with the bike on the center stand to see exactly where the fuel levels are in each carb. Below is a link describing the test - easy to do and accurate. It does not sound like rings. When you did the compression test was the engine fully warmed up, all spark plugs out, and the throttle all the way open? If not, the readings are not reliable. Ed

kzrider.com/forum/2-engine/580335-homead...at-level-tool#580344

yeah, comp test was done properly

you said "had a kwak dealer do the shims so valves should be perfect, "

I strongly second Patton that you should check these yourself. Then do a clear-tube test. Real (as opposed to bench) float height really makes a difference and it's the only way to measure it.