KR-1S.co.uk Forum

Just purchased 2 b type genuine pistons off ebay part No 13001-1372.Are these the ones that caused trouble with ring pegs falling out.Anyhow i need some rings,that would fit? where from and roughly how mutch.While im rambling on can i reuse the gugeon pin.Many thanks

Hi Gonzo, couldn't tell you about the pistons as it appears Kawasaki superseded the pistons part number by using the same part number

If you were to take a chance on them, I would hold out for a set of Kawasaki rings on ebay or I do believe these may still be available?

Give cradley kawasaki a call 01384 633455

Personally I wouldn't re-use the gudgeon pin or clips or the small end bearing. And all these parts are relatively inexpensive anyway.

Hope this helps?

these are not an original KR-pistons, but am just using these pictures to explain.



if your ring pegs look like this (installed halfway the groove), you've got the bad piston's, and the only good advice is to give them a good polish and put them on the shelf as display.

the later piston's had the pin sunck in the middle of the groove, like this :

Have also 1 later kr1s piston-part No 13001-1354 both have pegs half in the groove,however pegs are a little bigger on later type.Are earlier types realy THAT bad??

Gonzo355 wrote:Are earlier types realy THAT bad??

YES, they will come out eventualy and ruin you complete top-end

on the later version's, the peg is hidden behind the rings and can not come out.

Hello again so what pistons are recomended? why do people use tz pistons in track bikes do they also use them in road bikes? or does this req some sort of modification??

Gonzo355 wrote:Hello again so what pistons are recomended? why do people use tz pistons in track bikes do they also use them in road bikes? or does this req some sort of modification??

yep, "some"

you can buy original copy-piston's from Mitaka or ProX.

Tz pistons are shorter, so you need to machine the bottom of the barrels. This is not that straightforward as this removes too much meat and can lead to cracking. This can be sorted by welding to strengthen it, but it is all a lot of work.
You might consider all this work worth doing for a race engine but for the road- stick to standard pistons.

I looked at this a while ago, and I think oversize kmx rings fit - I might even still have a set

Issue is - do you trust the pegs ? Makes a horrible mess if they come out

viewtopic.php?t=234&highlight=rings

Didn't work in the kr, and wrong peg ends for the later 1s pistons. Same peg ends and diameter as the pistons you've got, but not sure about other dimensions. I'll have a look tonight and see if I've still got a set - you're welcome to them if they're any good.

Tommy