KR-1S.co.uk Forum

Upside down V twin with the intake on the ............top/bottom of the engine?

Never took to the upside down design.

What would be more interesting is the tandem twin inclined with the gearbox underneath.
That would lead to a very compact package suitable for a motor bike. The original design as used in Karts is too long for a bike.

A while ago at Cadwell was chatting to a chap from France (don't remember his name) who builds very quick international super Karts and after looking at my Kr's he showed me his 250cc motors he builds for the Karts, quite impressive and all manufactured in house, said he has a tuned road Kr1 and he based his Kart motors on the Kr motor as they are so good, he was pleasd to see a Kr going round Cadwell.

Not sure of any in-line two stroke kart engines. Plenty of tandem

Mark it wasn't FPE was it? http://www.pit-lane.biz/t875-technique-fpe-superkart though there engine is Rotax/Aprilia based....

It may be these engines Mark, maybe he was referring to the KR tandem, I don't speak French and his English was hard to understand but I did get the impression he likes the Kr motor, the kart engines were hard to see with side pods and bodywork around them.

That makes more sense the kr tandem

he did try to explain the bellows style power valves and lots of other things but my French and his English didn't work well together, but I thought he was trying to say he built every thing from scratch based on the KR motor, I could be wrong though ( language barrier and all that)

mj43 wrote:Never took to the upside down design.

What would be more interesting is the tandem twin inclined with the gearbox underneath.
That would lead to a very compact package suitable for a motor bike. The original design as used in Karts is too long for a bike.

Bob Martin would have loved to know that a 256 was to long for a bike when he managed to make this with same geometry of a RS250 NF5




Had a A Grader guest riding it after riding TZ250's and modern 600's couldn't believe a 6000 rpm wide power band.

FPE is based on a Rotax 256 the 256 could well have been copied from the KR 250/350 as that began in 75 Rotax was 78/79. Pneumatic valves have tiny ports in the exhaust duct that push the bellows up when the pressure rises a very old Rotax idea still used on the MAX kart engine/snowmobiles today

A home made Italian twin, would love if he made a run of them

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TwoStroke Institute wrote:A home made Italian twin, would love if he made a run of them

Now that is a thing of beauty, that is what I had in mind. I mentioned stacked inclined tandem as it is more compact and on a bike gives better weight distribution/geometry than the standard tandem layout.

Given the absence of a power valve I assume that engine was destined for a Kart?

Home made

Wow what an engineering achievement =D>

Awesome!
am i mistaken/bad eyesight but doesnt that great looking machine have "hydroformed" pipes?

Hey TSI.
Is that Bob Martin, formerly of Bob Martin Motorcycle Engineering?

mj43 wrote:
Now that is a thing of beauty, that is what I had in mind. I mentioned stacked inclined tandem as it is more compact and on a bike gives better weight distribution/geometry than the standard tandem layout.

Given the absence of a power valve I assume that engine was destined for a Kart?

A rather odd kart the concept might catch on though




I didn't do the pipes Dave just the engine(pipes were from a kart cut n shut to fit). Yes Scott was built by the late Bob Martin back in the early 80's (82 IIRC)