just got a motor in a box, got some questions

[CSR400EX]

i have just picked up a 250R motor in a box, and im wondering what all i have here. i got two cylinders, one has MF carved on it and the bore is a 72.5. the other is a stock cylinder with a 73.5 bore. also it has a spacer plate on the bottom end and the rod has CK109 on the side. i was told its an 86 motor, but im not sure. can someone help me find out what i got here and what will work??

[C-LEIGH RACING]

By having a spacer plate on the bottom end, it probably has a long rod crank & uses the 85/86 style of big bore piston. 73.50mm is last bore for the big bore sleeved cylinders.
MF carved in the side could mean MotoFast, they were 2 stroke porter some years ago.
86 models were good cases, but the transmission gears can bust easy if are old stock. Replaced new 86 gears were better made.
Neil

[CSR400EX]

i just went and measured the spacer plate and it was 4.6 or so. and im thinking they used a 87 rod in it. im thinking of using the motofast cylinder but the sleeve is cracked on one of the intake bridges. anyone know where i can get a replacement sleeve???

[dunatic]

northwest sleeve
superior sleeve

both located here in the portland oregon area.

[CSR400EX]

thanks everyone, im hoping to slowly piece it together and build a fast motor out of it. not sure what i want to put it in yet. i have a choice of a 400EX frame or a complete 86 ATC250R. i cant make up my mind :confused:

[86 Quad R]

i have a MF engraved cylinder that was on a project quad i got for my son a while back. it had been bored for a B/B sleeve and had fitted with a stock bore. after getting it dialed. it is one of the torqiest i've built.

got a pic of the engraving?

[CSR400EX]

i will get one up as soon as i can.

[SuperChris]

I have a cylinder at 68MM that has all three bridges on the sleeve cracked. I relieved them all with a rubber abrasive wheel and have ran three seasons on the same cylinder and piston.