MOPED ARMY

bearings dont really break in..and they don't make bad noises when new. if could be from yr crank not being centered in the crankcase... maybe rubbing along the walls. or your shims on yr clutchside not right. assuming if you have a needle bearing now you have an aftermarket crank, your shims might be pinching the clutchbell. these are all wild guesses. best bet is to take it all apart and look/listen whats grinding. goodluck.

really? i mean the bandit in me is impressed. but that might be yr problem. was there any play at all when you installed the piston? i mean it might be alright. crankrubbing is still a possibility. when you put the crank back in was it rubbing the sidewalls? that could make a chchchchch sound.

why is sanding a trip to seize-ville?

because the circle the needle bearing sits in will not be completely circular?

If so what is the best way to retrofit a needle bearing?

buy a DMP for $86.00

Or find a Korado crank.

I would not try "retrofitting". I mean I'm assuming the reason to put in a needle bearing is because you're putting a kit on your engine. If you're doing that and putting new bearings and seals on, then why not put an after-market crank it it too? Don't put the cart before the horse, whatever the fuck that means.

What happened is I took the needle bearing from another minarelli crank that for some reason had a weird left hand clutch nut, but the nut was stripped and I haven't been able to find another one anywhere. I tried putting the bearing in the stock crank, and it seemed fine. Except I didn't put the piston pin through the inside before I tried to put it through the crank, and of course when you actually do that it pushes the needles out a bit. So I rebuild and case matched the bottom end and put it on the ped, am putting the top end on and realize it doesn't fit. So I'm like FUCKGIN@#$@#(*$@(# and then FUCK IT IM SANDING IT so thats what I did. Now I'm kicking myself for not just waiting to find out that there is a needle bearing that would work in the stock crank...

Now I did polish the inside beside sanding it, but I'm sure its a bit uneven. I took it apart and looked at the needle bearings and two of them are nicked. Looks like I'm splitting the case again to put another crank in...

what if:

you just have a stock puch that your making fast:

you haven't cracked the case - but you did:

light porting - exhaust raising, high comp, perf exhaust etc.

it goes 40mph solid -

isn't a $6 needle bearing from treats a good mod?

What is the best, easiest way to work it in?

I don't think the needle bearing is going to add performance it just works better and doesn't get all wonky after lots of shredding...

thats BS. A stock brass busing works fine. I've seen many more busted needle bearings than seized brash bushings. I think this is a myth maybe the dutch brought over because they ride much differently. Their bikes do short drags at RPMs we only dream of. I'd say if you brass bushing were in good shape, it will function fine if the bike is kitted.

PS, Mark Ryan might be correct. Something may not be seated correctly on the shaft, con rod might be bent (it happens), or sanding the con rod made it all out of round and such as stated above.

Either way CHCHCHCHCHCHCHhchcHhchHhchc is obviously not a good thing. Were they NOS bearings? Were they 6202/6203, not 6202S/6203S (whatever tomos uses) or something silly?