CRM250SMR (using CR250/YZ490/KTM250SX internals)

Jeram
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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 29 Apr 2012, 09:28

cancel that optimism, the nikasil has flaked off the bored in one tiny section so It will need re-plating.

should have it up and running over winter.

Im thinking that due to the really good performance, I might even try and enter it in the 250 proddy racing class rather than supermoto.

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by back off road » 01 Jul 2012, 01:44

so after a f==k up is this a runner or a BIG BANG fail :?:
Im thinking about a bike with more valves than a powervalve

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 03 Jul 2012, 04:50

never a failure :)

cylinder is currently in the USA getting re-plated and a new Wosner piston.

just had the powerjet programmed wrong so it cut the fuel supply at high rpm instead of the other way around so it leaned out on me, everything else is a success on the bike.

should have her up and running again with the refreshed top end, better jetting, and EGT guage and an upgraded ECU that lets me control the Powervalve properly.

Im going to gear it down a bit too, I had it geared for 185kmh which is a bit unrealistic for short circuits on a naked bike.
so it should be much perkier with the PV working and shorter gearing...

looking forward to riding it again :)

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 03 Jul 2012, 09:45

should be back looking like this in a month

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 16 Aug 2012, 01:12

cylinder is back looks great!

just going to try some new porting techniques while I wait for the new power-valve controller to turn up. We got these techniques after studying an Aprilia RSA125 cylinder. allows you to boost top end RPM and HP without effecting bottom end. This technique can be applied to any two stroke.

It could actually work well on a stock CRM cylinder to make it a little more potent on top while keeping the characteristic bottom end.

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 22 Aug 2012, 01:59

ordered the Zeeltronic Powervalve controller.

So I will be using the ignitech ignition for spark duties only now, and will use the zeel for PV operation as the ignitechs PV operation was faulty.

All up $140 AUD inc postage (bout 100 pounds?)

http://www.zeeltronic.com/page/ppv-rz.php

Im also looking at Trail Techs new mini tachos and water temp guages... only $35 each!
http://www.trailtech.net/tto_tach-hour.html

Should have this thing going just in time as the weather is warming up here! Winter is almost over!

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by back off road » 25 Aug 2012, 02:03

Was the end result power over reliability ?

No excuses Jeram
Im thinking about a bike with more valves than a powervalve

Jeram
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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 26 Aug 2012, 12:45

back off road wrote:Was the end result power over reliability ?

No excuses Jeram
To put it in your words
back off road wrote:...most things have been covered already on the forum the best place to start is the < previous page > to find what you want

My motor is perfectly reliable, was simply human error (my error).

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 26 Aug 2012, 12:49

haha

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by knackeredMk1 » 07 Dec 2012, 21:11

Six months since the seizure any news :?: . One of your other forums has deleted you :?: The other has no posts since April :? .

Even at 'mates rates' there has been a lot of money spent.

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 09 Dec 2012, 12:25

Build thread is still on PBMAG forum, I asked for the other threads to be removed from other sites as there were too many trolls.

I wouldnt say too much money spent, this bike has cost me virtually nothing except for the cost of the bike.
All the mugen bits, forks, wheels, cylinder, carb, ignition have all been sold off and covered the cost of all the performance bits.


IM currently preoccupied with a much faster bike, its a golden era 500GP replica using a TZR chassis and a 421cc two stroke shop motor that puts out 90 odd hp and weighs 125kgs.
Shes all up and running and is a formidable beast to ride, as terrifyingly exilerating as an 80s GP machine

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Retro » 11 Dec 2012, 12:55

:BB

Jeram
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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 18 Dec 2012, 02:48

coincidentally, Im going to have all my bits back before Christmas so that I can get the CRM going again for some January and February.

However the motor wont be running for more than a few months as I am currently in talks with a cylinder casting professional who is looking into making a batch of one off cylinders for both my 2T single cylinder racebikes.
The KTMito cylinder its at its limits and cannot be pushed any further which is disappointing, while the CR cylinder I am running in the CRM is less than ideal for making good power.
Essentially it will be a scaled up Aprilia GP cylinder, around 300cc for the CRM and around 400cc for my 380 motor.

Shouldn't be nearly as expensive as one would think, as the cylinders permanent tooling (moulds etc) is mostly already done from when he made a YZ360 and some ultralight racing motors so now it just needs to be adapted to fit each of my motors which is more or less taken care of during the final machining on the CNC machine.

Will be quite fun to have a torquey 65hp, 6 speed, counterbalanced motor in the CRM,
I might be needing one of those TRX billet baskets though!

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 27 Jan 2013, 08:49

amongst preparing my TZR421 for some classic road racing events and commissioning a GP spec cylinder to be designed and manufactured for my road racer, I've managed to find time to get all the bits together to get the CRM beast going again.

Replated cylinder with a recessed exhaust bridge
new Wosner SX250 forged piston which has been machined to fit my engine
Zeeltronic powervalve controller (couldnt get my ignition to control mine)
Zeeltronic handheld programmer for altering the PV settings anywhere, anytime


Should have her all put back together in the next couple weekends.

I've got a go pro replica camera so will be able to take some video from the first trackday.

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Re: CRM250SMR (using CR250/YZ490/KTM250SX internals)

Post by Jeram » 28 Jan 2013, 12:56

today I made the copper head gasket, made the base gaskets, modified the piston so it doesnt scrape the oil off the bore, checked the ring gap and double checked the exh and transfer port timing.

The timing is still a little high for my liking at 197/129 but that's why we have powervalves.

Just have to slap the cylinder on in the next few days, then connect up the new race ignition which has a special little feature to prevent seizures when you close the throttle at the end of the straights, as well as a map switch, gear counting and traction control.

once thats done this week Ill just have to repair the exhaust mount bracket that I damaged and install an EGT and a coolant temp guage.


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