KR-1S.co.uk Forum

gday all , im considering doing a run of crankcase halves out of 6061 aluminium billet for the KR250A1 is anyone interested?
cheers

I don't have a Kr250, so can't you make a crankcase for a KR1 that can take 2 KX250 cylinders ?

That would interested me

Don't need standard cases for mine, but ones that give me the option of fitting the KX 250 (or similar) top end would definately get my interest, as standard barrels are hard to find in good nick, and the idea of a 350cc Tandem Twin is really appealing. [-o<

Edit: Thing is, the KX is a piston port induction and not rotary reed valve like the KR. Sure there must be something that could fit though.


What sort of price would you be looking at for them?

Cheers, Scott

gday guys ...i work for an automation company over here in oz called john hart . my kr250a1 cases are rooted so i am trying to get the guys to plot the dimensions of the cases so i have a 5 axis program that can produce the cases for me as a demo. with luck i can run a few sets off. price? no idea yet but i think the material is about $200au each before machining. just an idea but the more who are interested the cheaper it gets.anyway ill keep you posted.....cheers

If you just need some cases, I'm pretty sure I got some spare somewhere. The biggest prob I have is finding good barrells (only got 1 good set), hence the appeal of fitting different barrels.

gday scottaKR well yes all i really need is a set of cases, 1 crank,not sure which one , magneto,pistons , rings and im off. billet cases was just an idea i had seeings as i work in automation and robotics. i havent even asked anyone yet! just a lowly contract fitter and turner with good contacts...lol.i reckon billet cases would be along term fix to a reocuring problem though. ill still follow the idea up. cheers

What's this recurring problem your haveing, as I've never had any case issues. Pistons and rings from a KMX125 (2mm O/S) are the most likely option to replace the KR slugs (since theyre NLA) but may need some slight mods (not sure if anyone has fitted them yet, but I'll be trying them in my next build).
Good luck, and remember to post up a pic of your bike on the site.

Cheers, Scott.

Finding a good KR top-end is much more difficult than a bottom-end. No-one's asked me about replacement cases yet via my site.

Don't think it'd be worth you getting some copies of the standard cases made up, but if you were planning to do something special using bigger or more modern barrels as Scott suggested then I'd be interested in a set or two.

StrokerBoy wrote:Finding a good KR top-end is much more difficult than a bottom-end. No-one's asked me about replacement cases yet via my site.

Don't think it'd be worth you getting some copies of the standard cases made up, but if you were planning to do something special using bigger or more modern barrels as Scott suggested then I'd be interested in a set or two.

Credit where credit is due, it was Jans Idea to make the cases to suit other barrels, I just liked the thought of it.
After compareing the 2 side by side though, I think KR1 or KR1-S barrels could be used as a replacement with the custom cases, giving some nice ports and powervalves, though we'd need a custom head to go with it.
Not sure what other barrels may suit this application, as I don't have access to a lot of different strocker barrels.
This would also give the opportunity to use more common pistons as well. =D>

On a side note, I have been looking at porting a spare damaged barrel to KR1-S spec since they're almost identical layout, just different sizes and timing. If there's enough meat to cope with it, I may try it with a set to be re-plated for a future evolution of my motor. [-o<

Chopper: I'd be interested to see what the problem is that youve been haveing with the standard cases. I don't live that far away from you either (in Boronia) so if you do need parts, let me know.

gday guys....i had a kr250 a1 around 1988....did heaps of ks...then one day ..bang....so ...i opened it up..and what had hapened i think is...seized in one barrel...loads up all 4 crankshaft bearing housings ....result....one side both bearing inserts cracked...the other side... inserts rattle around like a dick in a bucket...........fast forward 20 years and i deceide to replace all my favoutite bikes ive had,,,rgv, zx7r and the mighty kr...i bought a basket case on ebay and guess what?....exactly the same damage to cases but this time including snapped off end of one crank and shattered magnet in flywheel/magneto
...now i could resleeve cases (scotch key them in etc ) but i thought if i could get the dimensions of the cases digitaly the it would be a piece of piss to get some made up>>now as for different barels etc i can dig it guys but thats not where im at at the moment but i doubt it would be to hard to alter programme once originals were being produced>>>please bear with me as this is awork in progress and i hope i did not give the impression iwas parting them off like washers on a lathe

cheers guys and thanks for your intrest>>>ill post photos as soon as i can figure out how to>>lol>>>chopper

gday scottakr thanks for the offer and it would be great to catch up work and sbk are overunning me at the minute but as soon as i can ill drop over cheers chopper

Was that the KR250 out near Cockatoo was it?
I went and had a look at that one myself, and had about the same damage that youve described, but the barrels were also in need of plating from memory.

yep thats the one...lucky me!!!! if i cant do this engine ill just end up doing a complete green and white resto sans motor. im not convinced if this is the right project so i may just wreck it...problem is id love to get it up and running

chopper wrote:yep thats the one...lucky me!!!! if i cant do this engine ill just end up doing a complete green and white resto sans motor. im not convinced if this is the right project so i may just wreck it...problem is id love to get it up and running

Well, I have nearly everything youll need to fix her up other than good barrels, so just put together a list of what you need and I'll see what I can do for you (maybe just a complete'ish bottom end?). As for barrels, youll just have get the ones you have re-plated unless you can fluke upon a good pair somewhere.

Good luck with it whichever way you decide to go mate.
Cheers, Scott.