ZXR250 topend questions

[Stevezxr]

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[Aufitt]

it all looked the same i didn't bother measuring anything just swapped the pistons barrels and head

call the lawyer!

[Frogger]

as far as i knew they were , i did a balius / zxr250 swap and after having problems inside i tried to make a good motor out of the 2 and they were both the same inside. the difference in the models was just cosmetic i thought.

i had the same problem as you with over heating and water in the oil , after about 20 rebuilds it turned out to be a dodgy water pump leaking water into the engine.

[g0zer]

So my question is before i freak out at the people that sold me the wrong top end are the interchangeable

I don't think they are if the bore is that much bigger the centers would be off am i barking up the wrong tree or should i be freeking out at a wrecker dude for almost destroying my motor

if they are +1mm then that is not going to be interchangable. do you have the boxes they came in? are they standard size OEM kwaka pistons for the C bikes?

maybe there is only aftermarket proX or wiseco available? and they have been supplied oversized requiring a rebore.

[Stevezxr]

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[g0zer]

in your original post, you mentioned they supplied you with a complete top end including barrels? so you are saying they have supplied C pistons with A barrels?

[Stevezxr]

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[Stevezxr]

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[g0zer]

im confused, so the pistons are +1mm compared to your original A pistons but you have installed C barrels... so why do they need to be interchangable?

[Stevezxr]

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[Frogger]

i just measured some old pistons i have and they are 48,89 or something cant remember exact now. they are from the A model or the balius but both worked in either cylinders. did u get brand new piston's ? if so where from as i was sure you couldnt get them.

[Stevezxr]

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[Paraletic]

what about your conrods mate? and crank? obviousley either one or both of these will be different to your orginal. and on the same train of thought how big and did you remove the lip at the top of the bore. you could have broken a ring on the lip. is the gouguing on the thrust face or side of the bore? new rings installed correctly? any damage to head?

personally i dont think you will have a shot at getting anything out of a wrecker, in my opinion it is up to you to measure it.

[Stevezxr]

Ok i did some measuring

Bore is different
stroke is different
length of piston is different
height of piston pin is different from top of piston to top of pin
Length of sleeve insert is different
The barrel section itself is taller

Got to love buying stuff from a wrecker

[g0zer]

what about your conrods mate? and crank?

yeah good point.

Ok i did some measuring

Bore is different
stroke is different
length of piston is different
height of piston pin is different from top of piston to top of pin
Length of sleeve insert is different
The barrel section itself is taller

Got to love buying stuff from a wrecker

mmm that sucks

are you sure you cannot source aftermarket pistons? take one of your pistons down to ray eason and see if he can find a match for it?

[Stevezxr]

The rods and crank are the A model
All i did was buy a second hand barrel pistons cams and head and cam retainer and fit them to the A model bottom end

I did ask for an A model top end not a C model

Here is a picture would you be able pick they are different


16112011(001).jpg

[2Old2BTHISMAD]

Any chance you could tell us what the piston pin height and the skirt length of the "c" pistons please. Gotta do one myself and would like to know before I buy pistons.
Cheers