CRM250 SMR with CR cylinder

[Jeram]

Hey fellas,

While procrastinating about the KTMito, I Got my supermoto race bike fired up on the weekend for the first time.

Heres what I started with

1999 basket case CRM250AR with probably 20hp at the wheel in its state of tune.



rebuilt bottom end
137.5mm rod from a yz490
custom machined crank to accept the wider rod
KTM250SX piston with custom machined oiling holes
2005 CR250 cylinder, transfer ports reshaped, stud holes offsef, spigot machined down, 5mm cylinder spacer. bored to 68.5mm (265cc) and Nikasilled.
CR250 cylinder head, machined to Superkart specs, toroidal shape
stock 05 CR250 expansion chamber for the beast overall spread of power for now untill a custom pipe is made
Vforce 3 reed cage
custom made alloy intake boot
RM250 PWK39mm with TPS
modified flywheel
she drinks 100octane + a few additives with 20:1 AGIP castor/synth

Electronics are taken care of by an ignitech programable ignition unit

chassis:
powdercoated frame
marzochi 45mm shiver forks
rebuilt and resprung CRM showa shock
320mm wave disc
husky SMR 320 disc adapater bracket with 65mm caliper bolt spacing (ala ducati/aprilia)
Aprilia RSV caliper
braided lines
mito wheels
machined down rear disc
CRF rear master cylinder
new plastics and custom designed graphics
BT003 tires


Final issues to be resolved before first trackday:

-a battery to turn the ignition system on as kicking the engine over doesnt quiet produce the minimum 9V to create spark. My 12V 1.3Ah battery turned up today, its about the size of a cigarette packet so will fit nicely, Im going to just wire it up to a handlebar button so that I can only use it for starting the bike as my charging system/capacitor produces more than enough juice to power the bike

-servo motor gremlins, Iv contacted ignitech as Im convinced there is a fault with my programable ignition box because the servo is about as productive as a retarded 3 year old.



final product

[TMKIWI]

Now we know about the bike, 2T put up.
Nice.

[2T Institute]

Some of our mods would work a treat on yur CR 250 Callum.

[SachsGS]

So the CR250 powervalve is being actuated by the CRM servo motor? Why the YZ 490 rod?

[msmola2002]

greater rod length to stroke ratio.

[2T Institute]

So the CR250 powervalve is being actuated by the CRM servo motor? Why the YZ 490 rod?

Yes CR250 has a servo powered PV. With the rod, the CRM rod is NLA so the long swap was fesable, benefits of a longer rod are well known.

[TotalNZ]

Some of our mods would work a treat on yur CR 250 Callum.

Are you talking to me 2T? yeah was just looking at my CR thinking she needs some love.

[2T Institute]

Some of our mods would work a treat on yur CR 250 Callum.

Are you talking to me 2T? yeah was just looking at my CR thinking she needs some love.

One of the benefits of old age

[cnrcpla]

How much HP did it make after the tune up?

[Jeram]

How much HP did it make after the tune up?

No dyno yet.

Gota get the servo motor working first and heat cycle the piston, then it's dyno time

Hoping for very high 40s with the stock pipe and perhaps crack into the 50s once a custom pipe is made. But that's just a guess. What's going to be more interesting is the midrange which I hope will be massive with the long rod.

[Jeram]

a few vids from easter that I forgot to post up

ignition timing was way off, PV was locked open, and jetting felt rich in mid range.

Iv since done a full top end tear down and inspect... all looks good apart from a slight leak in head gasket and polished piston skirt.
So I made a new head gasket and cross hatched the piston, then made some pretty serious changes to the ignition.

Now the bike runs much nicer than in the videos bellow and there is no more spooge flying out the exhaust.

The bike is booked into to do a trackday next friday