CRM cafe racer

[badcat]

Thought you might like to see what I did to one of my CRM's......
(if I can work out how to put a picture up??)

[voodookid37]

i'm sure we would.....

have a wee look in faq.............all the info re getting a picture up on there.

[Jeram]

or just post the link to it :)

[badcat]

here you are, 89 CRM frame, 01 CR250 motor, XR400SM rims, GS400 forks, 90kg, 50 Bhp, ali bodywork by yours truly ;)
http://www.pipeburn.com/home/2010/9/25/ ... racer.html

[Jeram]

ahh yeah, Iv seen that one :)

Im glad someone else is running a CR motor in a CRM frame ... well mines a CR top end on a CRM bottom end, but same thing :)

nice one.

who made the pipes? one of yours?

[badcat]

me of course, anyway, how did you get to fit a cr top end on your CRM??? power valve an all?...

[Jeram]

stud patterns are almost identical, just need to offset the rear two by a few mm.

then a little bit of machining on the bottom of the cylinder so that it fits in the cases...

a maico 137.5mm rod
a KTM SX250 piston

so the rod ends up being 12.5mm longer than the CR250 rod :D and combine that with the CRMs larger crank case volume, itl be a very torquey, agressive, revy motor.

hopeing to have her fired up before XMAS.



hows yours to ride? fun id imagine?

[badcat]

cool, are you using the late model CR cylinder with the PV controller?

[Jeram]

yeah, 03-07 were the case induction cylinders, but the 05-07 had a more durable exhaust bridge (cracking) and better mid range so I grabbed one off ebay that was replated.

PV and ignition are taken care of by an Ignitech ignition unit...

http://s70.photobucket.com/albums/i92/S ... 030506.jpg
http://s70.photobucket.com/albums/i92/S ... 030507.jpg



but more about your bike haha

[badcat]

never had a problem with my 01 CR cylinder even when I was racing, did have a couple of shock moments when changing the piston discovering half the skirt missing, how that made it out through the exhaust I'll never know???:)

[badcat]

my favourite CR was the 91 with the huge dual exhaust chamber, seemed a bit more pokey, still got the engine in need of a rebuild, will get round to it one day, it was my first so maybe a little favouritism going on :)

[Jeram]

wow, ate a skirt and lived to tell the tale haha

must have fractures and caught on the way down on the exh port, then simply flew out the exhaust... but the bigger question is how did it fit through the stinger of the pipe? unless it was shattered into a heap of tiny peices!

[badcat]

there was no evidence of dents in the cylinder head or piston crown, happened a couple of times, the last time I changed it just had a crack in it, all on the inlet side, no wonder Honda say you need to change it every 8 hours!!

[Jeram]

two things.

run a wosner/wiseco forged piston and you wont get this problem... this is all too common in cast honda pistons and that is why I have NEVER bought a cast piston for ANY of my bikes.

also, make sure you drill the exhaust bridge holes on the piston skirt, these will help lube and cool the exh bridge a little better :)
the wiseco piston has instructions on how to do this and but a quick google search which tell you all about it :)

[Jeram]

ps: Im double checking the validity of the second point with my resident 2T guru :P

It seems to have its advantages and disadvatanges..

more reliability, but small amount of air/fuel lost out exhaust.

Pic of oil holes:
http://www.pilotodyssey.com/PO/download ... p?id=14401