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Won't start. Very low compression. 9 years 3 months ago #8562

  • Tyler
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I agree keep looking into what is going on, did you find valve clearances out of speck? Your cam chain idler is typical for these bikes, and it appears someone put a zx-1100 tensioner on the bike, but it appears that it is not working, or has exceeded its adjustment range because other components have worn or stretched.

Get your tensioner issue figured out and verify your cam timing is correct, then proceed to check valve clearances. Then you should have a good idea of what is actually going on with your engine. None of this would take much money or time to do.

You must of coarse follow your factory service manual to the letter when doing this work, its not difficult by any means but a mistake timing the cams can cost you dearly!

I had my head ported by a race shop in PA, Cavanaugh Racing. He did a beautiful job. Cams must be custom ground fro 1300, Web cams and Megacycle cams can do this work but... your getting into some more advanced engine building and if your really going to take advantage of porting work you'll need a more aggressive cam and at that point I would recommend strongly you verify the minimum valve clearance to the piston by mocking up the engine with clay on top the piston. And you really should degree the cams for best results. This is all do-able, it take some research, time and of coarse money, money, money...

I did a comprehensive overhaul including some expensive custom made pistons, and solid flow matched port job, and some other goodies and spent no where near $4500... probably about half that.

Be patient, for now get a few basic checks done on your engine and evaluate what is wrong.
1981 KZ1300
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Won't start. Very low compression. 9 years 3 months ago #8572

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Thanks guys. I don't think I am going to give up on her yet. I'm going to talk to a few more people here and see what I can come up with. I really don't think its a good idea for me to attempt this on my own.

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Won't start. Very low compression. 9 years 3 months ago #8578

  • Lucien-Harpress
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If you need any help, just let me know. I literally JUST got done doing this to mine.
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Won't start. Very low compression. 9 years 3 months ago #8585

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Want to move in for a few days? ;)

In all seriousness, here is where I'm at.

I have no idea if the rings need replacing. The valve cover is off and the cam chain slipped out of place when I was pushing on it see how slack it was so if the timing wasn't off before it sure as hell is now.

Without a leak down test is there any other way to test the condition of the rings without putting everything back together to see if the rings freed up after dumping diesel down the plug holes? I know the head has to come off to replace that nylon wheel and I will measure the chain to see if it is within tolerance. I'm assuming when the head is off I can test the valve clearances etc?

I won't be doing this on my own. My Harley mechanic/friend will be helping me. It will cost but he has been treating me more than fairly this far.

I need to find a place to to the valves. Is this a typical machine shop type thing?

I'm sorry I'm such an idiot lol. I know the terminology but I honestly don't have much a clue otherwise.

Thanks again fellas.

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Won't start. Very low compression. 9 years 3 months ago #8587

  • Lucien-Harpress
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Let's see...

I wouldn't worry about rings just yet. Usually, rings start stuck (low compression) then free up as you run it (compression comes up). I"m assuming you dumped some oil down each spark plug hole and re-did the compression test for each, with no change? That would mean your rings are probably good.

If the cam chain slipped, you'll definitely have to re-set it before you do any kind of compression testing or engine movement. Otherwise you're looking at bent valves, or worse. Take the intake cam (rear) off, then re-set the cam timing as stated in the manual (I can get details if you need them).

To take the head off, you'll have to remove the upper radiator hose connector (two allen bolts), the carbs (done) and exhaust (not all the way- just drop them down out of the way). In addition to the main cap nuts, there are four small bolts on the backside of the engine- don't forget them!

Valve clearances can be checked with the head off, and is slightly easier than with the motor in the bike. You'll just have to prop the head up off your workbench a little, though- the valves protrude beyond the bottom of the head. The guy who helped set my valve clearances took a couple of 2x4 and screwed them to the edges of the head, using the outer two stud holes with a set of screws and large washers. Just be sure you don't lose any buckets or shims as you're taking the cams on and off. If they do come out, make sure they all go back in the same place they came out of.

A good machine shop should be able to do a valve job, at least re-seating all of them. This will change your valve clearances, so be prepared to learn how to adjust those. Before you take the head in, however, flip it over on your workbench and fill each cylinder top with fuel. If any leaks out, you have a bad valve.

While you have the head off, do yourself a favor and get a new set of valve stem seals. I bought the ones I needed, and the machine shop I took my head to put the on while they had the valves out. Now's the best time to do so.

The best advice I can give is to get comfy with the Service Manual. It does a good job of laying out each step needed to take the head off, and the correct way to put it back together. Before you do anything, read up on it first so you know what to expect. It is, bar none, the best resource you can have for any kind of work on this bike.

Best of luck!
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Won't start. Very low compression. 9 years 3 months ago #8591

  • Kawboy
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