KR-1S.co.uk Forum

Hey all,

I've had this kr250a in the too hard basket section of the shed for 2 years and I've decided to get it going 'cause it went like stink when it did......
I've done the primary gear dampers as per the manual, (the thing never started when it was hot) and found that the two cranks seem to be from different models! The front crank has the "kr250a" crank with the updated primary gear and a left-handed nut on the end (the one described in the back of the manual). The back one is the other style with no nut on the end. I don't suppose it matters as the bike ran pretty well regardless, but has anyone seen this before? Am I making any sense?

Hi Sheik,
My manual dosn't say anything in the back about the updated crank with the left handed nut retaining the primary gears. That said, I actually have one of the late motors (I intially thought it had been modified till I read your post ) amoung my spares that had been used for a go-kart. I can't imagine it'll make a huge difference haveing the two different cranks as long as the dampers are both setup to match.
Would you be able to scan the back part of the manual where it describes this update and post it up or send it to me.
I'm sure strokerboy would love a copy too if he dosn't already have it.

Cheers, Scott.

Yeah the innards of the newer primary gear (the one with the nut) are assemble differently and the stack height to be measured is different. This made no difference to me as I made my own washers anyway, but I thought it was a bit weird that they were different. I'll scan the back of the manual tonight or tomorrow and post it here if I can figure out how....

They changed the design after a year of production. 1984 A model doesn't have the nut, the 1985-on A2 model does. They each have different specs for shimming them right too.

Don't suppose there's any reason why you can't mix and match, as you seem to have found.

A cranks
A2 cranks

I'll scan the supplement bit that shows the update for the A2 and post it here. In the meantime, this is the spec for the original primary gear :

Thanks Tim.
I'm going to need that suppliment as I'm just starting to strip down my A2 motor and prep it for the bike, so the specs will be very handy. Might even get the dremel out and flow the cases a bit.

Lol Yeah what he said......

I just measured the stack and made a washer the appropriate thickness rather then using the table in the book. I doubt you could ever find the factory items......

Might even get the dremel out and flow the cases a bit.

Yeah go on, if you're gonna open the cases up ya may as well go the whole hog

StrokerBoy wrote:I'll scan the supplement bit that shows the update for the A2 and post it here.

Sorry, I should have done this before...

The only changes between A and A2 models are limited to the primary gears, and the 3 pages from the A2 supplement can now be found at the bottom of the Servicing Page on my site.

As The Sheik says, the genuine shims shouldn't be needed as long as the overall stack dimensions are correct. The details for the A2 model are :