TOPIC:

After I rebuilt my 77 kz 1000 to replace all the gaskets the motor now makes a noise that I think sounds like the cam chain rubbing on the front of the engine case. Is this possible? The bike runs fine with no missing. What else could this be?

Did you remove all the cam chain bits and inspect them carefully when you rebuilt the engine? Did you install new rubber dampeners on the pieces where these are normally installed?

I would look to see if the little rubber dampeners are in place. The idler gear shafts are notched and have a small piece of black rubber to cut down noise under them. Is cam chain correct for crankshaft. The cam chain gear on the crankshaft can have different number of teeth depending on model of bike. Get it wrong and you could have too long of a chain resulting in chain slop that the adjuster cannot adjust for. If it is too long, can't say how long engine will last but down side is it might throw off the chain (at hgigh revs(?))and get pistons and valves out of synch (not good).

Post edited by: RomSpaceKnight, at: 2005/12/11 11:44

At the front of the cylinder block is a cam chain guide (part number 12053-019). These can (and do) break and should be replaced if there is any sign of wear or cracks.

When you pulled the engine apart what did you replace? Did you completely dismantle the engine?

I would check if the chain tensioner is functioning correctly first (it's the easiest!). Although, not at the front of motor, it may not be tensioning the chain.
Note for Rom'knight. The camshaft/ valves would jam up if camshaft and crank-shaft teeth were mis-matched. Been there!

RegardZ

When I rebuilt the engine it was due to a major leak in the gasket between the #3 and 4 cylinders. I simly took the engine apart, replaced gaskets and put it back together. It sounds like I should replace some of the parts involved with the cam chain. Any recommendations? Looks like I'll need to be contacting Jeff @ Z1 Enterprises!

Jeff at www.z1enterprises.com will know what parts you need. I would get the little rubber dampeners and swap them out. In addition, carefully inspect the idler assembly on top the head. These are the most expensive piece and I haven't seen them wear as fast as some of the other parts. You have a couple of wheel type guides. These ride in bearings and the rubber between the guide and bearings gets brittle and can fall apart. These probably don't cost all that much. There is the rubber rear guide piece that is retained in the cylinder block in the back and is what the tensioner pushes on. Use an impact driver and get it out and CAREFULLY inspect it. These things can look good but the rubber OFTEN is cracked. You can't really see cracks until you flex the piece a bit. These are NOT expensive and I would replace it. The rubber stuff in the cam chain assembly is what gets old, brittle and cracks and first you have noise, then you have problems... replace all of it you can!

Last bit of advice... the cam chain. Either split the cases and use a NEW endless cam chain or get one with a master link. The master link fits over the pins in the chain and the pins must be staked. This means you have to dimple the pins so the side plate doesn't fall off. I personally feel that if you do it right, it works as well as an endless chain as that is how the manufacturer of the chain secures the side plates. The correct tool makes it easy. Jeff can help you with the tool. It can be done with a punch if you have the cylinder off by just moving the new chain to the side of the bike and using a hard part on the frame as a back stop so you can hold the chain and bang on the pins (once you have the plate in place). It could also be done without removing the cylinder block if you had a buddy hold something hard behind the chain as you dimpled the pins...

I think you have learned something really important and that's to use your ears. I'm amazed at how important it is to know what the well tuned engine 'should' sound like. We can often sort out a lot of problems by keeping the 'right' sound in mind. I recently noticed a slight change in engine sound and ended up tweaking my timing back plate and heypresto what a difference.

Hope you get it sorted with the cam chain. BTW unbalanced carbs can cause pretty horrendous cam chain noise on the 650 so before unbolting the head you might want to double check that your carbs are all nicely balanced out.

I got it wrong by 1 tooth once counted 28 not 29 (I think is right count, manual not in front of me). It ran but did make a "clicking" sound. Even made a pass up the strip. Luckily did no damage. You can be out a tiny bit with lotsa luck. What if you put on a camchain for a 16 tooth crank instead of a 15 tooth crank? That was my line of thought.