1995 zx7 Engine Trouble-please help.

[jaysons-zx7r]

Ok guys and gals. Im sick to my stomach since last night when my paint and body guy called me up and said that his friend who is a mechanic (backyard) said that he tested the compression in my pistons and was only getting 155 to 160 per. He said that they should be doing 240-260(I cant remember which). He recommended me to buy new pistons and rings and bore out the cylinders to get the compression back to where it should be.

He said that a way he does to test it is to drop and very small drop of oil on the top and that re-seals the rings for a few minutes. He said that when he did that it ran like it was BRAND NEW AGAIN.

My question is this..... Is this something that HAS to be done?
Is there any other alternative?
Does ANYONE on here know where I can get
pistons and rings for under 200?
Just what are my options?



PLEASE HELP!!!: My email is jasonwilkins78@yahoo.com

[Lawn Masters]

look at a service manual. 155-160 sounds perfectly acceptable and WELL within your service limits. if he'd said your compression was down in the double digits, I'd say be worried.

[jaysons-zx7r]

Ill try and look online and see what the compression ratio should be. Thanks!

[Lawn Masters]

To me, 180 sounds more correct for a 4 stroke motor like the ZX7 than 200+ pounds of compression. but this is just me too.

[jaysons-zx7r]

my service manual says:

11.5 : 1

From what I can find on ebay and just a search for pistons, Im going to end up spending a small fortune on this damn bike and I dont want to sell it to someone like it is because I dont feel I can get my 3500 that I have already spent or Id put it up for sale right now.

Its too bad too because Im almost done getting a 3 stage paintjob.

I wish I knew what to do.

[Lawn Masters]

ignore the guy's advise and just ride it til it dies. he clearly has no idea how to fix a motor anyways. restoring good compression would merely be a set of new rings, and a cylinder honing.

if it runs right now, leave it alone and ride it. dont get scared cause some backyard fool says it needs work. I know the backyard mechanic type well. he's tryin to make a quick couple bucks by having him "rebuild" your motor.

[Lawn Masters]

Let me suggest soemthing before you resgn yourself to HAVING to fix a nonexistant problem. take it to the kawasaki dealer and have THEM do a compression test. a certified dealer/shop will know how much compression your bike should have and can tell you if theres a problem.

[WeBeToyz]

11:1 compression ratio for this bike is correct.

Usable compression range is 140-220 psi. If all your cylinders are within a few pounds of each other (say 3-5) then I wouldn't be worried. My '94 is in the low 150's across, but with 37,000 miles it still runs strong.

It is not uncommon for the valve seats to wear prematurely on these bikes. Do you have any lifter noise? If so, that's good - valves should always be adjusted to the loose side for these bikes.

Mr. Backyard performed a wet compression test - did he tell you what your numbers were for a dry compression test? A dry should always be ran before a wet one. If he wasn't smart enough to know that then you need to quarantine his backyard...

[Ericthejet]

The engine was "hot" for this test?

[Lawn Masters]

there ya go. like i said, your motor is likely just fine and doesnt need anything at all.