Engine rebuild - timing chain

[andy63]

Hi.

I bought two 454LTDs as a job lot, both with about 12000 miles. The history of the two bikes goes like this.

Bike #1 Last owner was using it daily, one day it wouldn’t start at all, even tried to bump start it with out success. That was 9 years ago. Around the time it started playing up he strip the top end down leaving the pistons still fitted. I’ll come back to that later.

Bike #2. The original owner had a small fire around the crank case where the belt drive housing is. The flames licked the main wiring harness under the fuel tank. He parked the bike and left it. Owner of bike #1 bought it as spares bike.

Work done by myself on Bike #1:
1. Cleaned out the oil sump.
2. Replaced all the cylinder head valve guide seals and ground in the valves.
3. Refitted the piston chamber housing and fitted the cylinder head.

Here’s the problem;

I have fitted the camshafts & checked the valve clearances as per the Kawasaki manual. With a finger in the cam chain tensioner hole, I rotate the engine with a 13mm wrench in a clockwise direction. It seems that when the left piston nears the top of the cylinder there is a slight restriction. At first I thought the timing was out but I have checked it and all appears to be correct. I have tried the same procedure on bike #2 (spark plugs fitted as they are well tight in the cylinder head) I feel a slight amount of compression and a small amount of restriction which releases as quickly as it came. I removed the oil sump guard from engine of bike #1. My son hand-cranked the engine while I looked into the workings of the engine. The timing chain is not kinked and rotates freely over the crank. The engine appears not to be in gear but the restriction sounds like its coming from within the engine.

Any suggestions as I’m at my wits end. Arrrrrgh.

[zekkfett]

The "restriction" you refer to is the pistons in the cylinders building compression; then as you keep rotating, the exhaust valves will open and let that compression release.

All sounds completely normal to me...

[andy63]

Thanks for your reply.

The engine I'm rebuilding has the spark plugs removed so I can observe the piston position , but there's still a restriction.

Any ideas?

[zekkfett]

Hmmm..... *scratches head....* Perhaps the camshaft timing has jumped a tooth or two and the piston at the top of it's travel is hitting (one of) the valve(s) at the bottom of it's travel....

Just a guess, without having hands on the engine.... Perhaps a better description of the problem might help us out...

[eaglerider]

I tend to agree with zekk...sounds like the cams and cam chain are not set right, causing the valves to be out of time with the pistons. Go back to your manual (hope u have one, as this procedure is very difficult without one) and review and set everything per instructions.

[hemi]

I don't know how hard your restriction is, but I can fee some when turning my engine and it is certainly from the valve springs.