HELP - Need Some Advice From Engine Experts

Hey gang - I was putting my motor back together tonight after swapping in the Gpz cams. I blew the tach drive on the exhaust cam last week and decided it was as good a time as any to go the final distance on the 810 build.

I got the new cams and valve clearances done on the weekend and finally got a few hours tonight in the garage and was ready to fire everything up tonight.

Put the head back on, set the motor to TDC on 1 & 4, set the cams as per the factory markings bolted on the cam caps, the idler gear and the new APE cam chain adjuster with the proper tension. Everything looked good to this point.

Turned the engine over with a 17mm wrench and everything seemed smooth and nice. The cams were moving the buckets up and down nicely and there were no strange noises or friction.

When I checked the 1 & 4 markings and cam markings again after rotating the engine several times, the cams were off by a couple of teeth.

I had measured the cam chain for wear and it came in within the wear allowances at 161 mm for a 20 link length. The factory manual says 160-162.5 is good.

So, what do you think is happening? Is there a chance that I blew a couple of teeth on the primary gear on the crankshaft? If this is the case I should feel the chain jumping-right?

I am puzzled as to why this thing kept on jumping a couple of teeth, I chalked it up to having a bad adjuster which should have been solved with the new one from APE.

Something else is happening and I am too tired to continue chasing the problem tonight.

Thanks in advance for your opinions.

Cheers-Colin Firth-Ontario Canada

maybe the cam moved during installing one of the cams. What ever, just adjust the cam/cams individually and keep the cam tentioner set

I am thinking you would have heard a pop noise if it jumped a couple of teeth, did both cams move the same amount?

Make sure the cam gears have the
same amount of teeth as the original
ones.The cams have to match the marks
after they are bolted down and the
idler gear is secure and the camchain
tensioner is adjusted.Thats why you
count the chain links from intake to
exhaust cam.The cams will rotate slightly
when you install the idler sprocket.

tjettim wrote:

Make sure the cam gears have the
same amount of teeth as the original
ones.The cams have to match the marks
after they are bolted down and the
idler gear is secure and the camchain
tensioner is adjusted.Thats why you
count the chain links from intake to
exhaust cam.The cams will rotate slightly
when you install the idler sprocket.

I swapped the cam sprockets from my other Kz 750cams (they were the same ones from the original Kz650 cams) onto the new Gpz cams so there shouldn't be a problem. I will count them tonight just to confirm as this is a possibility to look at.

I sure as hell don't want to have to pull the motor and split the cases if I don't have to.

Any more suggestions folks??

Cheers-Colin Firth

Just double check everything.
It is usually something simple.

reborn650 wrote:

Turned the engine over with a 17mm wrench and everything seemed smooth and nice. . .When I checked the 1 & 4 markings and cam markings again after rotating the engine several times, the cams were off by a couple of teeth.

You turned the engine clockwise only, correct?

When you indicate the cams are off, can you give some additional information?

Which cam, in relation to which cam, in relation to TDC on the crank.

Did the marks advance on the chain or retard in relation to TDC on the crank?

What marks are you referencing on the engine? There are arrows and dots and numbers and letters and sometimes paint used as match marks.

tjettim wrote:

Make sure the cam gears have the
same amount of teeth as the original
ones.The cams have to match the marks
after they are bolted down and the
idler gear is secure and the camchain
tensioner is adjusted.Thats why you
count the chain links from intake to
exhaust cam.The cams will rotate slightly
when you install the idler sprocket.

I snuck home at lunchtime and pulled the exhaust cam to compare the tooth count from the spockets. They were both 34 tooth which seems right.

Tonight I'm am going to take a look with a bright light down through the head and cylinders to do a visual on the sprocket (on the crank) that the cam chain rides on. I am hopeful that it is in good order and my glitch is something that I might have overlooked while tired last night.

Cheers-Colin Firth

I rebuild about a dozen of the things a year... the problem you are having is that you didn't pull the cam chain taught on the crank sprocket down on the bottom... you THINK you did... hehehe but you didn't! This is about as common an issue as any on a KZ. The cam chain tends to kink some down at the crank... you tug and pull and think you have it extended but it ain't. You install the cams, turn the engine over and find you are a tooth off... IT REALLY HELPS to have an extra set of hands to pull the chain after wiggling/jiggling and making sure it is solidly on the crank sprocket and hold it while sticking the exhaust cam in place.

wiredgeorge wrote:

I rebuild about a dozen of the things a year... the problem you are having is that you didn't pull the cam chain taught on the crank sprocket down on the bottom... you THINK you did... hehehe but you didn't! This is about as common an issue as any on a KZ. The cam chain tends to kink some down at the crank... you tug and pull and think you have it extended but it ain't. You install the cams, turn the engine over and find you are a tooth off... IT REALLY HELPS to have an extra set of hands to pull the chain after wiggling/jiggling and making sure it is solidly on the crank sprocket and hold it while sticking the exhaust cam in place.

By George...I think you are right George. I am willing to bet this is the culprit as I had my son (kawasakikid) holding the cam chain and I told him not to pull it too tight as I didn't want to force anything. He was just following my instructions.

I can't call this a rookie mistake because I have been in this motor several times...successfully and I hadn't run into this problem before. Your experience with this happening to you makes me feel a little better:)

I pulled the head and jugs tonight just to make sure that there wasn't a problem with the crank sprocket. It was fine as were all rollers and cam chain adjuster gears.

I decided to bring the cylinders to my local machine shop and have the bottoms of the cyliners chamfered as this was not done on the 810 bore and it was a real pain in the arse fighting with the rings to get them to slide in. This should have been done by the motorcycle mechanic/machinist when the bore was first done, but it wasn't.

Tomorrow, with the chamfered jugs and another set of strong hands I will put everything back together with the confidence that the bottom end will be correct.

I will post my results when I get everything buttoned up.

Cheers-Colin Firth-Ontario Canada

George is right on the money, it's happened to me a couple of times.When you pull the chain tight rotate the motor a bit to make sure the chain is kink free.
Mark

Wow... if they didn't chamfer the liners how did you get the rings stuffed in the first time? I would think this is something you could do yourself with a die grinder. Has anyone tried this? The piston skirts don't come down that low so it doesn't seem like it would need to be a scientific thing... just never tried it... and as far as getting the cam chain pulled out... it can even seem to be pulled tight and still bunched up... the suggestion to roll the crank a bit is a VERY good one while somebody keeps tension on that chain!