I'm stumped

[Kevin]

A buddy of mine bought a 87 305 Kawasaki for his daughter. It has 6000 miles on it and has been sitting about a year. I've cleaned and synced the carbs twice and replaced the plugs. The compression is only 60 pounds in both cylinders. This seems very low to me. The little bike starts great,idles and sounds good but when you open it up on the road it has a missfire. I'm missing something here. Any suggestions?       

[Brian Moffet]

60 pounds is extremely low.  It's a compression ratio of about 4 to 1.   Try putting in a little (teaspoon) of oil into the cylinders and turn them over a while to spread it around to see if the rings are seating.  Usually a motorcycle is around 10 to 1 or more.

Brian

[Rick G]

When checking compression on bikes with vacuum carbs , its necessary to find some way to get the slides up,  otherwise you will get a low reading. One way is to pull the carbs during the test, another is to remove the cover on top of the carbs and pull the diaphragm/ slide combination up and out of the carb. You always want to test compression with wide open throttle , but vacuum carbs make it more difficult.

[Coil Coyle]

Adjust the valves, they are leaking

$0.02
;)
Coil

[Paul Mc]

Hi.

If the compression is low, be it rings or valves, then it shouldn't be too easy to start and it should be burning oil.
If it's a misfire (and not backfire), it suggests to me the fuel supply isn't great - possibly a kinked ventilation hose/similar. Dunno if that bike is vacuum tap, if it has a prime setting use that.
If it has an aftermarket fuel filter, change it - 6K miles is pretty low, valves should still be in reasonable condition and clearances should be okay.

If it was me, I'd try it on prime/ensure that she's getting fuel right and see if that makes a difference.

[Kevin]

We finished the 305 tonight. I adjusted the valves and rechecked the compression with the slides propped open. The compression was 120, both cylinders. We pulled the carbs back off and dissembled. The jets were previously cleaned and looked fine, but when we sprayed cleaner up through the pilot jet hole, one carb had much less flow into the carb throat.There are 3 small holes and 2 were partially plugged. We put the carbs in a harbour freight sonic cleaner filled with Berrymans carb dip for 45 minutes and then sprayed all the ports out and reassembled. I took the little bike out for a test ride and the little motor just screamed ;D. I have never seen this problem before, I usually clean the jets and spray and blow out the body. Ain't life sweet!!!   

[Kevin]

And I forgot to say, THANKS FOR THE HELP EVERYONE. ;D

[kwells]

Hey Kevin
Could you post a link to the sonic cleaner you used from Harbor Freight?

[Rick G]

I bought one in '03  but I returned it as it was too small to get the  bodies in to, Maybe they have a larger one now?

[Coil Coyle]

I just got the stainless body one they currently stock and it makes the California safe Berrymans work! It will do one carb at a time.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91957

I ran the Flying Pig's carbs for a half hour each and it even removed some of the white oxidation from body. The shaft seals seamed to have survived too. The little hole in the emulsion tubes were cleaned without any mechanical cleaning, just washed in water then dried with air blast.

I think it's a winner. The fluid pours back fine and the cleaner doesn't attack the stainless

$0.02
;)
Coil

[Kevin]

We used the 2.5 Liter model costs about $70.00. Both carbs fit in at the same time. They weren't completely submerged so they got flipped over.