KR-1S.co.uk Forum

Having bought myself a KR-1 project I find myself spending more and more time in the garage scratching my head

I had my rose tinted specs on when I bought it, but starting from scratch I'll know whats been done !

One cylinder is badly gouged, where a chunk of piston about 1/2" long between the rings has detonated itself and cracked the top of the piston.

Therefore a full strip down is on the cards.

Are internals readily available? Who are the best people for bearings, gasket, seals etc.

Also is a puller for the magneto available?

Any advise is greatfully received.

internals available, Yes. Except for conrods (KX or pattern) and crankshafts . Powervalve linkage pulleys also NLA, dunno about seals and bearings.

I just got a puller recently from a motocross shop, measured the thread I.D. on flywheel to tell him what size and its a reverse thread. few other bikes use the same size. It will be quite tight.

happy building

Hi Ped 250, KR1 man calling from down in sunny Bournemouth. Hope project is going well. With regards to crankshafts, Stan Stephens offers a full rebuild service, and prices appear on his website (all + vat), 01732-760337; also Grampian Motors 0151 9315009 are good. Give them a ring and I'm sure you won't be disappointed. Look foreward to hearing from you soon; Colin.

Hi Ped 250, KR1 man calling from down in sunny Bournemouth. Hope project is going well. With regards to crankshafts, Stan Stephens offers a full rebuild service, and prices appear on his website (all + vat), 01732-760337; also Grampian Motors 0151 9315009 are good. Give them a ring and I'm sure you won't be disappointed. Look foreward to hearing from you soon; Colin.

Hi Ped 250, KR1 man calling from down in sunny Bournemouth. Hope project is going well. With regards to crankshafts, Stan Stephens offers a full rebuild service, and prices appear on his website (all + vat), 01732-760337; also Grampian Motors 0151 9315009 are good. Give them a ring and I'm sure you won't be disappointed. Look foreward to hearing from you soon; Colin.

Z-power can get you all the bits like pistons rings gaskets etc. Stan stephens does an excellent crank rebuild as KR1man has stated a few times I think

be careful not to damage the powervalve pullies. KDX200 conrods are the same as the KR are they are available. Get the cylinders replated instead of buying new ones.

Thanks for the contacts elf & KR1 Man.
Havn't been in garage this week ( bloody work getting in the way) so I've not yet split crank cases, I have my fingers crossed about the crank as my wallet is empty and my flexible friends are fully flexed!

Hope to get some time this to do some more spannering (praying) as I just need to remove the magneto then I can split the cases and check over the crank, I hope this is ok or elsre it will put the anchors on the whole build.

I'll keep you posted !

seems a bit pointless splitting the bottom end if you can't afford to rebuild crank.

If you take outer cases off and the flywheel, you should be able to spin crank over and try lifting each end to feel for play. and check conrods

I found Grampian very expensive for crank parts and they refused to replace a faulty bearing

S.E.P were very good for parts or crank work

sometimes see s/h cranks on ebay or a cheap bottom end, make sure you wash out crankcases with 2t petrol or similar if you don't strip them.

Have fun

£220 from Grampian for my crank which I thought was a bit expensive

Can't fault Z power - knows his stuff, very quick service, and 10% off if you PM Al for discount code

I think Stan charged me about that for my crank as I had new big ends, as well as mains and seals changed.

Got another three blown cranks and one good un, waiting for rebuilds ATM. Also got two pairs of KR1S cylinders waiting for a full tune as well as three crank cases that need flowing. Oh and two cylinder heads that'll need sorting out as well