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General Two Stroke Talk / Re: KTM big bore kit.
« on: February 16, 2010, 03:51:51 PM »I will take the silence as a noi have a '99 380SX that i bought brand new that i have been wanting to get the motor into a modern KTM chassis. really i'm waiting to buy the finished product because i'm too lazy to do it myself. i did all the measuring for the job back in '08 and started looking for a rolling chassis. the 'Y' section of the front down tube/engine cradle has to be modified. the engine mounts don't fit and the cases have to be bored for the larger swingarm pivot bolt. head stay is different. engine mounts are the easy part to overcome. the 380 motor (and all '98-'02 250's and 300's) have a resonance chamber on the front of the motor that will hit the frame at the 'Y' section. i have seen some people who have done the conversion just fab up a flat plate to replace the chamber with. doing it this way would save the most grief as you could weld up the motor mounts and then bore the cases for the swing arm and hang the motor in. the pipe even fits in the existing mounts. i saw another conversion that cut the 'Y' section out and welded in a new one along with a new cradle and engine mounts to fit properly like Service Honda would do. i have seen a third one which was the craziest one of all. believe it or not the 380 crank fits in the new generation cases and the jug bolts on. this guy had slipped it together on one of those electric start 300 models. the primary gear on the 380 crank didn't work with the clutch basket gear though. he had to modify it somehow, i can't remember exactly. i think he had to modify the 300's gear to fit the 380's crank or he made a whole new one. i do remember that the cases finally cracked and broke at the kick starter shaft. there had been incidents of people breaking the original 380 cases in that area although my bike never had any problems. so i think that the 380 crank/new generation cases is not the way to go even though it was a neat idea. i wish i could just buy the rolling chassis set up ready to accept the engine out of my bike. no muss no fuss. and John, if you are ever in the midwest (MO/IL) and want to ride the 380SX feel free to get in touch with me. it is retired from MX and i only use it the few times a year i trail ride. it's the back up bike to my 250SX now.
OK try another approach, has anyone had any experience with the '02 (roughly) KTM 380 motor, and any chance they will fit the current 250sx chassis.
I expect at least 10 replies on this by this afternoon, so get busy people
well just to horrify the oil zealots, i will tell you that i almost always run a "witch's brew" of 2T oil. i routinely blend different brands together. a few years ago when the distributor Motorcycle Stuff was in it's final year of operation, i was given a sample 12L case of Repsol moto2T oil. they had just started carring the oil line. the stuff was clear like baby oil. you couldn't tell at a glance whether you had a gallon of premix or a gallon of straight gas. so i got a clean 5 gal. bucket and emptied the Repsol bottles into it then scoured the shop for half used bottles of any 2T oils i could find. i mixed in some Klotz R-50, Honda HP-2, Motul 800, Mobil 2T,and Redline. those oils were red and blue so they made purple and dyed the clear Repsol purple. i have ran that stuff through my mx bikes, both my outboard motors, chain saws, and weed wackers. i'm still using it up.