TOPIC:

I tested compression on my bike (83 KZ1100, unknown miles) and I got:
1. 80lbs
2. 61 lbs
3. 60 lbs, but I couldn't get the adapter to thread in far on this one
4. 87 lbs

Can a bike run well on such low compression? Did I not test it correctly? The bike isn't running so its cold, I did open the throttle all the way up and turn it over until the needle stopped. I'm using a harbor freight tester.

Story:
I was running to Lowe's and after pulling out of the parking lot and getting up to speed, I lost power. It would barely maintain speed. I got stopped at a red light and it died. It restarted once, but sounded terrible and didn't have any power still. I had it towed home, I pulled the spark plugs and cylinders 2, 3, and 4 looked fine (top picture). Number 1 is the bottom picture



I put in new spark plugs, then decided before running it to turn it over by hand, just to make sure I didn't jump timing(I didn't actually check timing I wanted to make sure it would turn over without hitting valves) or something. I turned it over and one of the cylinders started hissing. I assumed I blew the head gasket or a valve wasn't seating on cylinder 1 based on the spark plug. Either way I checked compression and thats what I got and I don't understand it.

How long since your last valve adjust? Has the bike been running as of late but it just crapped out? Reason for asking is because bikes that sit a long time often have sticky rings.

I haven't adjusted the valves since I've owned it ( a year). I did check them though, and all were in spec except for one that was just on the edge of spec. I didn't have the shim changing tool or any shims so I didn't mess with it.

Its been running fine, and then crapped out. It did shoot out a puff of white smoke after it sat for more than a day.

Aside from the winter time, I've been riding it since august of last year and have put ~2600 miles on it. The PO said that the original owner let it sit, then a bike shop bought it, then sold it to the PO and now its mine. Could the sticky rings lay dormant for several years?

Thanks, Matt

Is there a piece of metal imbedded in the side electrode in the lower pic? Based on what I can see, I bet something really bad happened in that cylinder.

I'd turn it over to TDC on that cylinder then using a light to see the piston.
Steve

TexasKZ:
No its just part of the spark plug flaking off. Comparing it to a spark plug color chart, it looks like it overheated.

SWest:
I looked and compared it to the other cylinders. All of them have carbon build up, but #1 is wet. Didn't notice any scratches or lines in the carbon even.

Would this mean I broke a ring?

Thanks, Matt

My bet would be valve guide seals. If the rings are "Sticky" that could be it too.
Steve

To replace the valve guide seals I would have to pull the head correct? And if I had sticky rings, then I would still have to pull the head correct?

My next steps would be to check valve clearances to confirm a valve not seating. Then regardless of the clearances pull the head off because if I have sticky rings I need to take it off anyway. Is that right?

Thanks, Matt

And the part number for valve seals is KI700-100019 correct? Available at z1

Check the valves then run it. They may free up. Get Viton seals.
Steve

All are in spec except for 2 intake valves. When I put my valve cover back on do I need to take out the auto tensioner on the engine? or is that just the kz550? Also there was no oil in the valve cover, it did sit for about 2 weeks though.

So adjust the valves, should I change the seals before I run it?

valve clearances are in mm:
ex in
1. .1 .05
2. .09 <.04
3. .09 <.04
4. .09 .13

All of that needs to be done, but in addition to that, what type of compression tester do you have?

Some don't have a check valve in the very tip. I was looking at a 550 and the owner did a compression test with a brand new gauge. He was getting readings in the 130's. I told him a 550 never has compression that low if it still runs ok. I used my two gauges. All cylinders were around 180. If there is no check valve in the tip that goes into the spark plug hole, the hose becomes part of the combustion chamber volume. Therefore the compression ratio becomes much lower than that of the actual motor.

The compression tester doesn't have the valve in the end of the hose. Is there an application for on like that? I'll probably return it, Whats the best bang for the buck gauge to get then?

Would it be worth it to order an assortment of shim sizes or should I just order what I need?
I was thinking:
Shim changing tool, ZSM001-113 or 57001-113
and A valve shim kit from z1, what size are the shims? 13 mm, 29.5 mm, or 25 mm?

Thanks, Matt