low compression blues

Hi Guys,

I have a kz1000p, that is suffering from hard cold starts. There are around 35000 miles on the clock.

I'm a little torqued at having to go with this but I am afraid the inevitable has occured. After cleaning the stock carbs and changing the float valves for new ones I have found that the engine will catch on one cyl as I roll it over as before, but it would appear that the coughing and sputtering/complaining on remaining cylinders would point to a perceived low compression condition. I have not done a leakdown test or a wet/dry compression test yet to verify for sure but I am suspect that this condition exists. I have some difficulty keeping the engine idled as i think the carburetor slides may be sluggish as well.

Looking at reboring cylinders and matching pistons. Also valve seats with new valves/seals etc.

Is there a way to source parts without getting my wallet beaten up too much?

First, the hard starting may be a carburetor issue and nothing else. While you may have cleaned them, perhaps you didn't clean how and where you should have. Second, check compression, adjust valves and ignition timing and then report back in. Your problems sound like they are either carburetor or tune up related.

Second, if you are thinking about a rebuild, first remove the cylinder head and cylinder/pistons. Measure the cylinder and pistons and figure out what the clearance is. If there is too much wear, you will need to buy new pistons and bore your cylinder. This is fairly expensive. If the pistons are within spec, you will need a hone and rings... far less expensive. At the same time, disassemble the cylinder head and go through it... essentially new valve stem oil seals and lap seats/valves to ensure a good seal unless you find that you have considerable wear and then you will need to do a valve job which will include valves and seats and possibly guides. This is much more expensive and the best indicater of whether this needs done is to disassemble and measure the stem height. If it is OVER spec, the valve job may be needed but if it is within spec, only clean up stuff as I noted...

Anyway, before you do this, if the bike has been ridden infrequently over the past few years, try some Yamaha Ring Free or Seafoam in your gas and perhaps that will free things up and bump compression if it is down...

Bean (baked bean, Heinz bean?) quietbean, beans never did anything for a quiet night in our home:) sorry just teasing.

Seriously Bean, if your bike's only done 35k miles and was running well before you started tweaking the carbs i'd be very suprised if it needs any work on it all until about 65k miles. The big 1000cc engine is probably rarely thrashed to the red line all the time so there's no reason it should be badly worn.

You can pick up a compression tester off the bay or elsewhere for cheap that is always a good start into engine maintainance. Check plug colour, sort the carbs and then if necessary do a top end strip, decoke, clean valves etc. but even then I'd be suprised if it'd need more than just a clean.

Even badly balanced carbs cause quite a few probs on these kwakers, a set of Carbtune II's is another great tool to smooth running.

BTW that really is a superb looking bike, like a 4cylinder Harley cruiser, I love those footplates and the seat - just great. Aren't you a bit young though to be riding such a big bike!