KR-1S.co.uk Forum

finally arrived yesterday, 64 mm bore barrels KTM EXC200 pistons
now porting, already suspicious for putting extra two boost ports (pegs on KTM pistons are a bit closer than on original), and my biggest worry..will be able to enlarge cylinderheads volume enough to have std compression.

sounds interesting....keep us updated

Looks really interesting =D>
Did you sleeve the barrels yourself?
Cheers,
Bernie

No more kips valves ?
If you are going to keep them, How are you going to make them turn with that flat spot ?

You do know that the biggest probleem when tuning a KR are the cracking cilinders arround the stud holes ? So going to 320cc, i‘d give It only moderate timings

Not easier to stick a big bored RD/YPVS in it?..........more power with reliabilty..

kips will be in, have to decide to grind barrel edge or valve itself...I'll give it a go with regular angles, if possible to match horizontal transfer flow..
exhaust bridges gives me worry aswell,..I'll just give it a go

sleves were done by friend of mine with manganese alloyed grey iron, 0.07 mm play (pistons are 63.95)

Is the stroke the same as standard or are you changing rods or altering cylinder height?

yatasaki wrote:kips will be in, have to decide to grind barrel edge or valve itself...

at first look, I don't think the sleeve is thick enough to grind it down that much at only 2 local places. I wouldn't risk it.

anyway, good luckk with it, hope you'll make a nice engine

Wow - those cylinder walls are thin. Does that not also concern you?

on a personal note : investing some money into a bigger KR engine would be better spent going for a longer stroke making it more square,
increasing bore add's cc's but does hardly enlarge the port area's, needed to feed the bigger cylinder.

but I guess that advise come too late

to enlarge closer to square is too big investment, and question is space between conrod and case..
sealing between combustion and water space will be done by copper gasket 0.2 mm thin but only around combustion space, rest of the water space will be filled by some silicone sealant (done on my present engine)
jackets are thin, but not more thicker than on my previous 56.00 sleeved barrels (still in excellent condition)
presently I'm running on original plated barrels but as there are two more engines to play with,why not you'll be informed regularly does it worth..not promising too much
arizona 200 barrels, and rd350..
naaaah, like it full kwak with kips

Love it =D>
More photos

Is there enough meat on the kips valve to accommodate a bush in the kips valve hole (just a bit thicker than the amount the sleeve protrudes) then skim the valve to fit in?

Cheers
Bernie

I don't know about you guys, but the main reason I didn't buy a Kr1 or a Kr1s when they came out, was I was waiting for the 350 and the 500.
I had a 500 triple and nothing less than a KR350 would have convinced me to downsize.
If only

500bernie wrote:I don't know about you guys, but the main reason I didn't buy a Kr1 or a Kr1s when they came out, was I was waiting for the 350 and the 500.

Have you read Stan Stephens book? He said a 350 KR1 would have been a fantastic bike...a great couple of chapters on Stans KR1/S racing exploits in the book..well worth a read.