KR-1S.co.uk Forum

Where should I send my barrels to be replated Also while we're talking top ends.What pitons,rings etc are recomended

pablo wrote:Where should I send my barrels to be replated

A lot of people sucessfully use BDK

http://www.bdkraceeng.co.uk/Replates.htm

pablo wrote: Also while we're talking top ends.What pistons,rings etc are recomended

I use Mitake pistons, as do quite a lot of other forum members IIRC:

Here's a link to them, BDK stocks them as well:

http://pjme.co.uk/acatalog/Kawasaki_KR1 ... p_End.html

Charles

Thanks charles,I've just been on the phone to BDK.Looks like thats where the barrels are going.

86-88 YZ125 pistons can be had very cheaply and a good upgrade to a single ring

TwoStroke Institute wrote:86-88 YZ125 pistons can be had very cheaply and a good upgrade to a single ring

Very interesting.
Are these a staight swap? And where does the ring-end sit in the bore?

Where it sits in a YZ Pinned on centre I think IIRC straight swap

TwoStroke Institute wrote:Where it sits in a YZ Pinned on centre I think IIRC straight swap

Guess I'll find out. Just won a genuine NOS Yam one on ebay for $15 delivered.

Nice pretty sure the TZ 56mm ring will go in if not there are plenty of YZ rings around. Nice score, the stock sizes are cheap as most YZ's have long since been rebored

if anyone is interested, firefoxracing on ebay sell '88 YZ125 piston kits for £66.50.

(This is not an advertisment!)

ScottaKR wrote:

TwoStroke Institute wrote:Where it sits in a YZ Pinned on centre I think IIRC straight swap

Guess I'll find out. Just won a genuine NOS Yam one on ebay for $15 delivered.

OK, so the piston turned up a couple weeks back and then just sat there as I had other things to do. Just gone out and dug out an old stock KR piston to compare it with and looks pretty promising.
The ring pin is in the centre as TSI said, with the dome looking slightly shallower. The gudgeon pin sits slightly lower in the piston too, meaning the piston will sit about 0.5mm (rough measurement) higher in the bore which could easily be accounted for by using thicker base gaskets I'd think. The skirt is also 6mm shorter on the inlet side, and about 10mm on the exhaust side, so it may tend to rock in the bore a bit more.
Put both of them on the digital scales, with the KR piston weighing 144.8gm and the YZ coming in at 133.3gm
All in all, it seems like it could be a good single ring piston for race engines without the need to machine and reinforce the base of your barrels.
I'll try and get some more acurate measurements soon.