hi all,i rang my local honda dealer today with engine number of engine fitted to see if they could tell my year/model that it came from,as i do have the original engine in garage,i know the one fitted isnt original,as i want to get a crank,are all 18 cranks the same,i have searched this and found a difference in center crank seal,also some one told me from the honda dealer that 1989/90 rs 250 cranks were the same ,my original engine is compleat except crank,has any one got a good 18 crank to sell,thanks
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NSR250 MC18

There are 2 different MC18 cranks using two different center main bearings and seals.

No, the RS250 cranks arn't the same. They have either the wrong center main bearings (depending on which MC18 cases you're trying to fit them in) or the wrong dia flywheels. They also have smller little ends for use with HRC pistons which are shorter than stock pistons so require barrel modification to make them work.

Add to that '90- have the wrong crank taper for the flywheel.

Apart from that they are a easy swap.

MC18 cranks are only ever going to get harder to find so if you find one treat it well.
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If I have to take the carbs off once more...

hi thanks for your reply,i was on here last night till 12 and cris applebees name came up a number of times,i rang him today and what a nice helpful guy,he said he would change 3x main bearings bigends and centre crank seal or 340 plus vat,i thorght that was not bad considerind price of 3x main bearings, but when i rang fowlers/lings for 2x outer crank seals they couldnt get them ,thanks rc45 im glad i didnt buy that rs crank now,[straight fit i was told], :shock
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NSR250 MC18