mekros wrote:Vertex claims they have the piston you need, I don't know if it is a big bore or standard piston though.

everyone has the piston, but nobody has it in 2mm oversize

mekros wrote:Do mitaka make a piston you could use?

Not that I know of.

If you can find one, let me know.

I just need a KTM250 - 1999 piston in a 68.50 size that isn't a wosner.

if your location is Australia like your name suggests, try Dave at Two Stroke Performance in Victoria.

He rebuilt, revalved and resprung mine for a very affordable price.

Otherwise try PROMECHA in melbourne

nope... I'm in a sticky situation at the momment. Wiseco stopped making the pistons I was using, so I ordered a Wossner piston but it was faulty, so I ordered another and it was faulty too. So I've concluded that all Wossner 1996-99 265cc KTM250SX pistons are faulty so I'm stuck without a piston for...

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...

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...

if you feel that you need more power, sell the CRM and buy a KTM 300/360/380

cheap, reliable and powerful

peak fuel efficiency is at 55 degrees any lower and the fuel droplet atomisation rate decreases, = larger fuel droplets = more fuel to do the same job as you dont get a complete burn peak power has been proven to keep on increase continually as the coolant temp is lowered, significant gains are achi...

paint the powervalve with a light colored paint pen then let the piston scratch it, where its rubbing will be obvious. a few minutes with a diegrinder will fix it. if the PV position where it contacts is outside of the normal usage range then you dont really need to worry about it as your PV will ne...

Yeah that's what I was thinking, don't suppose anyone knows the size and pitch of the temp sensor?! if thats all too hard there are other ways around it. just get a 19 or 20mm inline temp guage from trail tech. they are very affordable. you can run them through either their 39 dollar mini guage, or...

yeah sorry, I got a little bit distracted before half way through my post as I had to go and fire up the barbie to for the end of year/Xmas BBQ at work. yes so pretty much to get a performance cylinder with an 80mm bore to work you will need to have the following modifications done 1. crank rebuilt ...

because it will be designed for my motor (137.5mm rod, 18mm wrist pin which requires crank mods), and requires fly wheel and pickup mods to work with a programable ignition (complete bike rewire)

Stickman (of this forum. Last contact ~ a year ago) did 300cc - He had to move the PV out in the barrel to get the clearance. He also grafted a CR 250 barrel and head onto a CRM crank before this with much more success than Jeram has had to this point. Stickman used the engine in scooter racing. I'...

Just for the record, the AR can be rebored. you send it to a specialist such as Millenium with your new piston. for 200 dollars plus they will bore it and plate it for you. For a little extra, eric gore (whom is now part of millenium) will port it for you while its there. Also for those of you wanti...

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 o...