Wear spec - need help

Hi,

Checking my motor to see what has do be done on it. It was on a kz1000j1

Top end is now tear down.

All four cylinder are very closely the same.

Cylinder bore (up and down): 2.755mm
Piston: 2.746mm
Which make a clerance of: 2.755 - 2.746 = 0.009mm
Ring gap when install in bottom of cylinder: 0.018mm

Can someone help to see what need to be replace.

Thanks in advance for your helpfull advise,
Joce

Cylinder Inside Diameter
Standard 69.4 - 69.412mm and less than .01mm between any measurements

Service Limit 69.5 or more than .05mm difference between any two measurements

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Piston Diameter
Standard 69.342 - 69.351mm

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Piston/Cylinder Clearance
.043 - .07mm

Ok let be do the conversion correctly:

Cylinder bore (up and down): 69.977mm

Piston: 69.7484mm

Which make a clerance of: 69.977 - 69.748= 0.229mm

Ring gap when install in bottom of cylinder: 0.4572mm


Would it be possible that this is an oversize kit and cylinder bore? since piston are bigger than 69.351mm?

maybe the .5mm factory overbore kit was installed. I would re-check your measurements and conversions before deciding this was the case.

How many miles on this motor?

The motor has around 30,000 miles on it.

The piston are ART.

The previous owner told me it has been overbored but wasn't sure about it.

There is a mark on the ring that say 0.50

Would this be a clue?

I'm no expert, but sure as hell sounds like that that is the case. Hopefully one of the gurus will chime in and confirm it.

I've found that 1015cc kit has inside cylinder diameter of 70mm. Which is the same that I got (2,755 inch = 70mm)

Can someone tell me what is the size of the piston from a 1015cc kit.

This will help me a lot.

Many thanks,
Joce

No one?

I typed the info directly from the Kaw Service Manual... what more can I put in the post?

Piston Diameter
Standard 69.342 - 69.351mm

At standard piston will be between 69.342mm and 69.351mm

The number of cc of a J engine is 998 from what I beleive.

Your telling me that the 998cc and 1015cc have the same piston size?

jcote75 wrote:

The number of cc of a J engine is 998 from what I beleive.

Your telling me that the 998cc and 1015cc have the same piston size?

Joce:

The Kawasaki shop manual mentions two oversizes for the 998 engine. It gives no specs for either of the oversizes but does give specs on the standard size (which wiredgeorge posted). The piston sizes are different for the 998 and 1015 engines. However, the piston size on a 1015 bike (BEWARE, this is from the earlier A/B series) 69.94-.96mm (69.8mm service limit)...BUT, the stroke is the same for the J and A series motors (66mm) suggesting there may be some congruency