KR-1S.co.uk Forum

just found a place two doors down from my work that has a cnc machine...lathe etc...n he is putting o ring rockers on tr4/6 triumphs......he recons its easy to do it to my kr1s.....so.....

if i o ring the head the squish area is gonna change(cos its got no gasket in between) so do i put tz pistons in,sure i saw on mj's site that tz pistons r less hight from the crown to the small end pin... or raise the barrels(although wont that change port timing?)
wot do you guys do????

the first KR I had, was already O-ringed, and since a couple of years, I do it myself.

the only thing that changes is that your compression is a little bit higher, just use standard pistons (I do ).

don't use ordinary O-rings, they van't cope with the temperature (only to about 100°C). you need special ones

best thing about O-rings is, you can re-use them quite a few times, so one can easily open up the top-end without having to buy a new headgasket

thanx janbros....next question then...where do i get the o rings....???

I got my first from Heiden Tuning in Holland, the guy that had tuned my first engine.

I've ordered some new ones at Peleman in Leuven, Belgium if it exists in rubber, he can deliver 5euro for one.

find someone like that in Brittan over here, the compound they are made off is called "vitton" .

if you can't find them, I'll order some more, but it can take up to 2 weeks before I get them.

ok...ive found a company in the uk but what size do i need????

anyone from the uk that can help (come on elf/rc/mj etc)

thanx...

just looked on wikipedia n it seems it was a vitton o ring that blew up the chalenger rocket.....lucky our bikes dont run on liquid nitrogen(well maybe mj will try it someday... )

try asking on www.rgv250.co.uk the o ring conversion is a common mod on the rgv and there is lots of advice on there about it.
they should be able to reccomend a supplier and help with your questions.
also have a at look "the tuning works" for o rings, dont know if sean does em but its a good place to start

cheers col...

se tz250 o rings as there availible at a number of places such as padgetts, jim matthews, geoff greenham racing etc.

you need a 2mm thick O-ring.

I've measured the diameters off my head :

inner : 61mm, outer : 65.5mm

If my memory is correct, it's the inner one that matters, so you'll need 61mm O-rings 2 mm thick

top bloke...ive got tony at gibsons on the case(im only 20 mins away from em) n i was just about to post wot the sizes r....yet again...great info from great guys.... gonna take photo's of the project tomorrow..so watch this space..gonna keep one totally standard n the other is gonna get money thrown at it like tissue paper in a fire!!! ....
with all the info on modding on here i think itll cos a bomb..better give the bank manager a bj...
cheers guys..

Greeting to everyone, I'm new here.

Question:
unlike the RGV, on the KR1 the exhaust valve are open to the top of the cylinder.
So you need two little o-rings to seal them, otherwise coolant may go in the valves...
Or do you use only one o-ring for the inner to resist the high pressure in the cylinder and glue the rest?

I used normal o-rings (vitton) on other engines (liquid cooled) and had no problem, cause the o-ring don't get hotter as the coolant

do you meran the seal for the powervalves? if so then the job for them is to stop residue (oil) from dribbling all over the front of the barrels. its a messy affair when they fail due to the gunk but nothing to worry about. there availible from kawasaki. any news on the o-ring mod bungholeo? couild do with hjaving some me self as there a must for a race bike. let us know when you have decided on which spec/size orings you end using, cheers mate.

from memory head gasket is 0.2mm thick so going over to o rings will close up the squish by that amount.

I use 2.364" x 0.070" viton o rings. Where I got them from wasn't cheap - I am sure you can do better.

Rest of head sealed using h***a 3 bond.