1978 KZ650 High RPM

thanks for the input guys! I am hoping that this is ignition, since when I first bought the bike there was no problem except loose cam chain. I tensioned it twice, seems the bogging/low power came after this tweaking. Also messed with the deccel cable but I think thats back to where it was before. My friend seems convinced that I would have thrown my timing off when I adjusted the cam chain tension, is this feasable?
I plan to check valve clearances after my ignition advance/timing
Don't have a compression tester
And I need to pull the air filter out. It is a long chrome aftermarket box, not even sure where to get replacement filters.

DaveKZR wrote:

...My friend seems convinced that I would have thrown my timing off when I adjusted the cam chain tension, is this feasable?....

Highly doubtful, imo, presuming routine cam chain adjustment, and not some procedure underneath the valve cover whereby cam timing might have been adversely affected.

Good Fortune!

Agree with Patton, highly unlikely timing was thrown off.

To check if compression is "good", just put your thumb/finger over the spark plug hole, and crank the engine.
If it pops your finger off the hole no matter how hard you press, that engine will generally run good.

The air filters can be had from many places like dirtbike/mot shops. I prefer Z1 Enterprises myself.

GL!

Just a thought here, could improperly adjusted cam tension be a cause to my troubles? I did it twice, but have had uncertanty about where I stopped the shaft (the whole corner by 2/3 thing) Maybe today while I have the contact breaker plate off Ill retension the cam when i can see the advance more clearly. Hope this clears everything up because I am really feaning for how the bike ran last weekend
**side note, both times i tensioned the cam I was uncertain about the stopping point so i rotated more than two rotations, maybe as many as 5 or more. Could this do anything? or is it just imparitive that you rotate the two rotations?

Ok, here's the update. After each one of these adjustments I took the KZ for a ride. Each time the bike was very strong all the way through 3rd and part of 4th. Top end of 4th bogs and doesn't accelerate, and 5th bogs and doesn't really accelerate. Every once in awhile it pops in 1st at low rpm, but doesn't worry me much.
I verified the cam tension for sure this time, 2 rotations then the correct corner near 2/3.
The ignition advance seems fine if I am correct in assuming that it is the roundish object with somewhat of a point on one side attached to springs? I rotate it clockwise and two ears hit stops the the spring snaps it back pretty quick.
I took off the air cleaner and removed 1 layer of sheet air filter that was in this chrome air box. it was pretty dirty but the remaining material seemed fine. Cleaned the carb inlet boots and temporarily wrapped them with electrical tape to make sure of no leaks. When spraying wd around them I don't get a noticable surge. I sprayed just forward of the carbs and i got what seemed to be a slight bog, nothing drastic, but maybe a hint.
I am about to remove lube/inspect and reinstall the throttle cable. Then I guess comes timing? Anyone know any "tricks" to timing without the light and ohm meter?
One other thought of mine was fuel filter? could it possibly be not letting enough fuel at higher rpm?
And finally I took a picture of my ignition, I am thinking I might have the aftermarket electronic ignition? I don't see any "points"

My friend seems convinced that I would have thrown my timing off when I adjusted the cam chain tension, is this feasable?....

Wait one... Not necessarily throwing timing off in normal sense of the word but if his chain was way too slack during the adjustment thus allowing the chain to jump a tooth or two then yes, the timing would be off....

Just a thought....

Old Man Rock...say this is possible, what would be a possible correction? Would I just have to retime or would I need to open up the engine to manually adjust the cam chain?

It's a simple procedure...

Before doing so... you may want to order yourself a new valve cover gasket....

Remove the valve cover.... Count chain pins in regards to TDC and timing chain sprocket markings... Your manual should be abale to provide you the procedure....

This is for the KZ900.... basically to give you an idea but your KZ650 will most likely be different in pin counts and sprocket amrkings..... Other 650 members feel free to chime in...

Follow the manual for 1/4 TDC....

From the right side of the engine, your cam lobes should be parallel and facing each other as image on the right... If you jumped a tooth where pin counts are off, or the cams are after market not degreed correctly, whatever, the lobes would be off as in the left cam in the image on the left....



All of which your engine would still run pending number of teeth off but may lack power or operate as yours is....

I tend to follow the others where your problem lies elsewhere but as your friend mentioned and in the fact you adjusted the timing chain adjustment, it is possible you jumped a tooth count...

It is possible, done it myself where went through the adjustment and didn't tighten the lock nut tight enough... went for a ride and noticed didn't have the same spunk and chain was rattling more then normal....

Oops, what did I do... Right? :laugh:

Went through the process in the above procedure and sure enough, jumped a pin... Shit happens ya know, no big deal to fix...

Good luck

DaveKZR wrote:

...verified the cam tension for sure this time, 2 rotations then the correct corner near 2/3.
The ignition advance seems fine if I am correct in assuming that it is the roundish object with somewhat of a point on one side attached to springs? I rotate it clockwise and two ears hit stops the the spring snaps it back pretty quick.
I took off the air cleaner and removed 1 layer of sheet air filter that was in this chrome air box. it was pretty dirty but the remaining material seemed fine. Cleaned the carb inlet boots and temporarily wrapped them with electrical tape to make sure of no leaks. When spraying wd around them I don't get a noticable surge. I sprayed just forward of the carbs and i got what seemed to be a slight bog, nothing drastic, but maybe a hint.
I am about to remove lube/inspect and reinstall the throttle cable. Then I guess comes timing? Anyone know any "tricks" to timing without the light and ohm meter?
One other thought of mine was fuel filter? could it possibly be not letting enough fuel at higher rpm?
And finally I took a picture of my ignition, I am thinking I might have the aftermarket electronic ignition? I don't see any "points"

Couple of things ---
Advancer function seems okay.
Electrical tape won't stop intake leaks.
Original points have been replaced by later Kawasaki igniter style electronic ignition.
Ignition timing with points was adjustable.
Ignition timing with igniter is set at factory and is not adjustable.
Factory pre-set unadjustable ignition timing may be "checked" to verify accuracy, best with a strobe type timing light (also useful to verify advancer function).
Fuel starvation typically just progressively surges, without popping, etc.
Good Fortune!

Cleaned and lubed throttle cables, and checked compression. Both came out fine. When starting afterwards I got white smoke from the 1/2 exhaust pipe. After taking it out for a ride and getting on it smoke is gone..?? Anyway on the test ride, the KZ is very strong through 1-4 up until about 60, then on there's no more acceleration, and bogging in 5th....
Wondering if I should do 1/4 TDC first or check the carbs. I'm leaning away from carbs because this wasn't happening when I first got the bike, so seems it *should* be jetted right. I never got a chance to test just how fast it would go before it started messing up because I was waiting for a tire, I would cruise easy around 70 with no bogging though. Maybe I just didn't notice, but there was still plenty of accel in 5th before and no bogging so I'm sure it presented later. Maybe dirty jets/needles?
Opinions on which beast to take on first?

DaveKZR wrote:

...checked compression...came out fine....

Compression test isn't alone sufficient.
Should also check valve clearances.
Checking is the easy part, and they might be within spec.
Adjusting is more involved.

In any event, too tight valves could result in the reported issues.

Good Luck!