another cam chain ???

at least i think its my cam chain!! it only rattles at low idle and stops at/or around 1700 rpm, then once i hit around 4000, 4500 rpm or so it starts to sound like a plug wire cam off, and it snaps like a electrical spark arching!! ( best way i can describe it sorry!)
when i look down, i see no sings of any spark arching from any plug wires.

also i read a little on adjusting the cam chain, but didnt find any (exact) directions, can some one tell mne haw to do this? what nut tightens , what nut locks the adjustmenst? i have two and dont want to turn them the wrong way and lossen it more!!
i have the stock kz650 b-1 from "79"

If it's a 79 it has auto adjusing camchain tensioner, 78 and earlier are manual. you can tell by looking at your camchain tensioner assm on the back of the block. If it has just a single 10mm head bolt tightened up flush with the body of the tensioner, it's the auto adjusting type. If it has a 10mm head bolt with several threads showing and an additional 10mm head jam nut it's an earlier manual adjust type. If it's manual, you take off your points cover, turn the engine over clockwise with a 17mm socket until you see the cyl 2-3 timing marks then turn the engine clockwise just a little more until the plate has a flat cutout. Right at the point the timing plate turns to this flat area you stop the engine there. Now simply loosen the 10mm jamnut, then the 10mm bolt with threads showing on your tensioner a couple turns, then retignten them. That's it. Whole thing takes about 5 minutes.
steveo_4192003 wrote:

at least i think its my cam chain!! it only rattles at low idle and stops at/or around 1700 rpm, then once i hit around 4000, 4500 rpm or so it starts to sound like a plug wire cam off, and it snaps like a electrical spark arching!! ( best way i can describe it sorry!)
when i look down, i see no sings of any spark arching from any plug wires.

also i read a little on adjusting the cam chain, but didnt find any (exact) directions, can some one tell mne haw to do this? what nut tightens , what nut locks the adjustmenst? i have two and dont want to turn them the wrong way and lossen it more!!
i have the stock kz650 b-1 from "79"

sorry , it is a 77 not a 79

I also have a stock 1977 KZ650-B1. I have done this adjustment a several times. My engine is equipped with the auto-adjust can chain tensioner. I believe you will find that you have this version also if it was not changed-out by a previous owner.

Position the crankshaft as mentioned above. You will find the adjuster assembly sticking out of the back of the engine and between the 2-3 cylinders. On the underside of the adjuster assembly you will find the adjuster bolt head sticking out and facing down. Loosen its lock nut and loosen the adjuster nut. At this point the spring loaded auto-adjuster will automatically and silently slide the tensioner forward (if it was lose in the first place) and apply the correct spring tension. Tighten the adjuster bolt (5 to 6.5 ft.-lb.) to lock the cam chain adjuster in this new position and then tighten the lock nut. That's it.

I hope this helps. Best of success!

Early 650's have hyvo chain driven bottom ends that clunk and rattle at low rpms. Could that be the issue at low revs and another issue at higher rpms.

loosen the nut then loosen the bolt
a wrench on the crank with a little back and forth movement will scootch the very most adjustment the inner spring will give
tighten the bolt and then the nut

if there is only a bolt same thing loosen and retighten.

now if the spring is weak and you adjust it with no change to your problem, I would remove the spring and either replace it or strech it just a little to get more pressure. either way if it is weak time for new parts

i finaly got the cam chain tight and wow! so smooth and quite! but no i have another problem. i just loosend the nut and bolt then retigthend it, and this other problem occured

i started the bike and it ran great at idle (1150- 1250 rpms) and when i hit the throttle it bogged out like it got to much fuel and wont get going till it hits 3000 or more!
do i need to reset the timing, cause i took out the slack in the chain? did it mess up the timing or somthing else
the bike ran good just before i did this adjustment and i went for a quick ride after and have no low end power

all help will greatly be apprciated!

Your adjustment of the cam chain likely has nothing to do with the bogging. To make yourself comfortable, put the engine at TDC and remove the valve cover and count the links on your chain between the marks on your cam sprockets as specified in your shop manual. I don't know what that number is and what the marks say on a 650 but I am sure someone does. If I had the bogging you describe, my first step would be to clean/lube the mechanical ignition advance (under points cover on right / front of engine). You might then also check your ignition timing if your bike has points/condensor.

if you adjusted ignition timing or carburation while the camchain was out of adjustment go back over them once again. the cam chain needs to be tight and right BEFORE you set any other details. it'll make a difference in performance and smoothness.

also when a cam is a tooth off on the pin count between the cam sprockets inside the engine it will create very low engine vacuum on the synchro gague and diminished performance as well.

Since the points are triggered off the end of the crankshaft, adjusting the cam chain will do absolutely nothing to your ignition timing.

ok, a local man told me i my have my cam chain to tight!
is it possible for this to cause the systoms i described in my last post?

Post edited by: steveo_4192003, at: 2006/08/05 21:52

cam timing sounds off. there is no chance that it is too tight. you just loosen the adjuster and re tighten. the spring takes the slack up.

when the camchain gets loose typically a bike becomes hard to start and you tend to need to hold the starter button longer than normal 'til it lights up and finally starts.

your bike was fine until the camchain got properly adjusted right?

Post edited by: trippivot, at: 2006/08/06 13:54