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Discussion Starter · #1 · (Edited)
Project Aim: Convert an oddball 90's enduro two stroke in a competitive supermoto racebike. And to keep me distracted while I my long term project (The KTM380 supermono) slowly takes shape.

That 90s oddball enduro is a 1999 CRM250AR, only seen in Japan, Australia and the UK.
it was known for its torque, its miserable suspension and its Advance Radical combustion technology (shuts of spark at low load and diesels) .

Stock standard the bike puts out an incredible 25 rwhp and weighs in a 128kgs :p

My target is to come close to doubling this power for now, and once fully dialed in and set up I will try to push the motor further.

Some of the advantages that this motor has over the CR is that is has a 6speed transmission, a large crank case volume and a longer rod as stock (+7mm).
whether or not I can take advantage of these advantages and get them to outweight the disadvantages, only time will tell!

The bike I purchased for the build



It turned out to be a real lemon which was unfortunate, but the silver lining was that all the rare MUGEN parts on the bike including the head, ECU, Power Valve and silencer were converted into coin to spend on fixing the bike up.

The nightmare that awaits inside:

cracked piston


scored bore


odd damage to clutch basket


rust everywhere


A rod that was about to get "divorced" from the crankshaft. I think it was planning on taking a lump of my crank cases with it instead of the usual "house and the kids"


more to come shortly
 

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Discussion Starter · #2 · (Edited)
Ok, so enough of the bitching and moaning, and more of the actual build

first step in performance mods... the off the shelf bits

Stripped her down and tore the motor out


Full rebuild including all new bearings and seals, and lightly polished the cases


Vforce from a 90's CR250, bolt patterns match up


Had a go at making my own decals but copped it big time from some less open minded forums.


Found that a 2005 CR top end would fit onto the CRM with a small amount of machining


Ordered a re-coated cylinder from the USA with a 68.50 piston


rebuilt the crank with a maico 490 rod, it is both stronger and longer than stock.
12.5mm longer than a CR250, and 5.5mm longer than the CRM.
This will make the bike very torquey and rev hungry.
The Engmod2T simulator software is telling us that it will be very beneficial.

The crank webs needed to be machined back to use the wider rod, we decided not to install thrust washers, instead we got the tollerances perfect and will just use copious amounts of premix as recommended by my crank guru.


a stock CR250 2005 pipe will be used for now while Im getting the bike set up.
A SuperKart spec pipe will fabbed up later on if/when needed


more comming!
 

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Discussion Starter · #3 ·
I got some marzochi 45mm forks for the bike to replace the CRM units which were
bad to say the least... I was like riding a sofa/bike hybrid

These forks feel fantastic



painted my side covers gold


brakes from an Aprilia RSV1000R Mille and a Husky racing adapter bracket!
lucky find!


KTM250SX piston, lower comp height to compensate for the longer rod


billet intake manifold custom made in the USA


EBC 320mm Prolite race disc


FUK, just realised that my rod was too wide for my piston bosses... "TOO THE MILLING MACHIIIINE!!!!!!!!"


PWK Carb with TPS... 39.5mm


Test mounting everything, engines getting a little closer



As per all odball bikes, my ignition just had to be wierd... it had 7 pickup bars on the flywheel and twin single wire pick up coil.. What the hell! GRRRR
Took a few weeks to work out how the system worked, in the end I just ground all off them off accept for the one I needed to tell the aftermarket ECU when to spark.


Got my frame back from the powdercoaters


In she goes!
 

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Discussion Starter · #4 · (Edited)
Ignitech Race ECU

my first time wiring up and bike and programing it from scratch... and interesting experience to say the least but I feel like a bit of a guru now...



just wanted to see what itd look like with an underslung pipe. seems to fit well and wont hurt ground clearance, however my pipe would be twice as fat as this one :S


OEM bits turned up from bike bandit!


modified flywheel


slashed my face when I forgot to remove the diegrinder chuck!


The Cylinder with machining instructions


spent an evening getting the powervale machined back by hand so that it stopped fowling on the piston




piston comparison, CR VS KTMSX (both 68.50mm)


slowly starting to look like a Supermoto with the 90's marchesinis and the Bridstone BT003's fitted



my custom designed graphics turned up from the UK... Shiny!






modified the frame to accept a CRF450 rear master cylinder


made a rear strut while the rear shock is getting rebuilt


modified the KTM piston by adding oil holes for the bridge


got the rear disc lined up by machining it down and offsetting


Intalled an 02 sensor


with a special 2T bung to increase sensor life


made a fluid catch can


started lockwiring


Oh and cant forget the black gripper seat mod.. looks much better now!



where shes at now...



Things to do:

Get the cylinder finished and installed
mill the head
install the new shock
and maybe a set of fat bars as the risers will allow me to drop the forks through a little more :D

start her up :)
 

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Nice...Lotta work put in so far!
 

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Discussion Starter · #8 · (Edited)
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.

no nasty cheap multicolor anodising, just silver anodised with some tastful machining marks etched in some areas that shout "hey Im a sexy CNC'd part look at me"

 

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Amazing bike GREAT BUILD!!! is that bike injected or premix from the factory? I think they were oil injected but Im not sure!
 

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Discussion Starter · #10 ·
Amazing bike GREAT BUILD!!! is that bike injected or premix from the factory? I think they were oil injected but Im not sure!
Cheers,
From the factory its Injected. But iv disconnected it for now as I want to run large amounts of castor which is normally premix only. But iv also recently learned that castor can be oil injected in warmer climates so I might reconnect the injection one day.
 

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Cheers,
From the factory its Injected. But iv disconnected it for now as I want to run large amounts of castor which is normally premix only. But iv also recently learned that castor can be oil injected in warmer climates so I might reconnect the injection one day.
Unreal bike build! Are there any of these bikes in the states? Where are some good places to go to get more info. on the CRM? I always wondered about doing a oil injected 2 stroke.
 

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Discussion Starter · #12 ·
Unreal bike build! Are there any of these bikes in the states? Where are some good places to go to get more info. on the CRM? I always wondered about doing a oil injected 2 stroke.
Try crm250.com
There would only b a handful of them in the states so I wouldn't count on being able to find one.
If you can't find the info your looking for just ask.

But with the new euro regs fast aproaching, expect to see some oil injected and possibly port fuel injected 2ts in the next 12mnths.
 

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I take it with your build appearing here, you've been thrown off the other forum again?
 

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God damn sweer build! Where are these money trees? You have a great mind to come up with this sort of build.
 

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Discussion Starter · #15 · (Edited)
I take it with your build appearing here, you've been thrown off the other forum again?
Hi Marty, nice to see you too.

Iv been a member here for a year I think, but I left SMA for a few reasons..

I'm finding this place much more friendly, as you can see there are no smartarse trouble making replies, which is really nice for a change!
 

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that thing is SWEET! much jealous. i like the tastful 90's look, like the best graphics the 90's could have ever produced.
 

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Hi Marty, nice to see you too.

Iv been a member here for a year I think, but I left SMA for a few reasons..

I'm finding this place much more friendly, as you can see there are no smartarse trouble making replies, which is really nice for a change!

You didn't "leave"... You were banned it seems? Nevermind... Don't forget the dyno day on the 28th... It would be interesting to see the power output/power curve. If you can't make it, my new bike will be in getting dyno'd early new year - I can sort some runs for you...

Hartwell have now changed the race rules so all mx bikes will run in their own class.. Be a good chance to come racing. There will even be a chick out there racing..
 

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Discussion Starter · #18 ·
You didn't "leave"... You were banned it seems? Nevermind... Don't forget the dyno day on the 28th... It would be interesting to see the power output/power curve. If you can't make it, my new bike will be in getting dyno'd early new year - I can sort some runs for you...

Hartwell have now changed the race rules so all mx bikes will run in their own class.. Be a good chance to come racing. There will even be a chick out there racing..
Might gate rash the dyno day if I can get it running nicely before then. Will be at broadford in mid jan getting her set up, got a champions trackday voucher for Xmas. And if struggling to get it set up right I'l do a half day at the dyno.
 

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Gate rash? Is that a two stroke thing? Is there a cream for it?

Mine wont be dyno'd on the day... The boys will check mine over in no rush, but I'll leave it to sit there so people can look at it...
 

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Discussion Starter · #20 ·
Gate rash? Is that a two stroke thing? Is there a cream for it?

Mine wont be dyno'd on the day... The boys will check mine over in no rush, but I'll leave it to sit there so people can look at it...
Yeah, I caught it in kings cross last weekend... Nasty rash and the itch is a killer

-gate crash

If two stroke institute comes down from Newcastle that weekend for the island classic I might book out the dyno early that morning before the dyno day coz he will be able to get the ignition curve and pv set up a lot quicker than me.
 
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