CR(M)250AR SUPERMOTO BUILD

[Jeram]

just to do something different, I thought Id try an O2 sensor for tuning

It came up on one of the forum classifieds, and I simply couldnt resist as it was about $300 worth of kit, for just $120 delivered.

combined with an extended bung, I hope to recess the sensor up high enough so that it is out of the direct flow which will reduce its exposure to the oil and hopefully extend its life a little








whether or not it works properly, I dunno, but it seems like a fun experiment for $100...
using plug chops, piston inspections, my bum dyno and this set up will hopefully give me the best chance of getting the bike properly set up.
because of the scavenging, I beleive that the ratio Im looking for is around 12-13:1

either going to place the sensor in the middle of the chamber in the upwards position, or between the stinger and the silencer... havnt decided yet...

[Jeram]

actually, apparently the best place for them on a 2T is the baffle cone.

even better, it will be completely hidden, and if it doesnt work Ill plug the hole and nobody will ever know it was there.

[Jeram]

got the sensor wired in today... looks to be a good set up.

I wired the calibration button into my throttle set up

only issue now is that Im getting an error 9 code from the LED light. that made me panic until I realized that error 9 is just a low battery warning (Im powering the whole bike with two 6v torch batteries)
so that should all be fine and good one the bike is running

[Jeram]

shock turned up, and is now fully apart

that was quick

a big thanks to DMCCA racing

[Jeram]

fixed up the OEM airbox, the plastic was knackered so I covered it with some good quality satin black vinyl... looks much nicer now

Before



After




then luckily I remembered to install the Exh bridge lubrication holes in the piston... cant believe I almost forgot.
So I spent a good hour polishing and deburring the holes to make sure there are no issues. then cleaned all the silicone carbide off the piston.

[Jeram]

little 2T 02 bung turned up. looks like it will do the trick.

its actual purpose is to act as a heat sink for turbo cars and drag cars where the exh gas temp is too high for the sensor.

but it separating the 02 sensor from the hot flows, it also removes it from the direct path of the oil.

[Jeram]

$5 catch can, got a carbon bike bottle holder on its way to do the proper bottle restraining duties

[Jeram]

gota love the chinese... the only country which is nice enough to make blinged shorty folding levers for the odd-ball CRM250AR

absolutely brilliant quality, just like ASVs or Pazzos.

[Jeram]

just got back from holidays and thought Id head back out to the shed.

finished off the catch can.

tried to get it nice and tidy.


did some gearing calcs and shes spot on, should put 190 in the top of 6th with my current 14/42 gearing.

only thing left to do while waiting for the shock and cylinder is to hook up the chain...

[Jeram]

chain and crash sliders

[Jeram]

After an exhaustive search the ebc disc is going in the bin. The bobbins are stuffed and are not replaceable on my model.

I was really keen to try out the Chinese discs because on a few local forums they have been rated very high by people who track ride and have metalworking and disc brake experience in there line of work.

So iv ordered a set of chinga discs haha

Getting closer with the cylinder but have decided to oring the top. Ordered a grooving tool for the lathe from the uk. Should have that in 2 weeks

Other good news, my shock has been fully rebuilt with new shims and spring. Will be fitting that tonight hopefully

[Jeram]

looks good!, re shimmed and re sprung

color matched to the frame nicely!

thanks to DMCC for his great work!


just waiting on new bush for the top shock mount... should be here on tuesday

[JonW]

steaming ahead Jeram! Do you have pics of the sensor install?

[Jeram]

sensor not fully installed yet,
Its all wired up and Iv got all the bits but I want to bolt the cylinder on first so that I can fit the pipe exactly as it will sit when the bike is running... that way I can find the perfect location on the baffle cone so the the o2 sensor sits hard up against the frame just under the fuel tank

so will have some pics of the o2 sensor in a couple weeks once the cylinder is installed. Im hoping to get it looking really neat like a factory finish.

untill then hopefully Ill have time to install the new disc installed and the shock.

Almost ready to fire it up, getting real impatient about getting back to the trackdays!! cant wait.
but pretty much everything else is done, so once the cylinder and head are finished Ill just have to set the ignition program up properly and then take her to the drags for some cheap 'dyno' tuning with the 02 sensor.

speaking of 02 sensors, I found another way to increase the life of them on 2Ts even more.
you fire the bike up without the sensor installed (using the 2T bung to limit the leak through the hole or put the plug screw in) warm up the bike first, and then put the sensor in.

[Jeram]

New disc installed, much better than expected.