NU205 and NU2205 Bearing Confusion!

[TurboTrev]

I have an innocenti GP150 with its original innocenti crank which I am retaining when the engine is rebuilt and my query relates to innocenti cranks only (not aftermarket ones).

I've read that an innocenti GP150 crank needs the NU205 mag housing bearing because the crank has a narrow shoulder, meaning that the NU2205 cannot be used as it only fits innocenti GP200 cranks which have a wider shoulder. However, I've also read that the NU2205 can be used with an innocenti GP150 crank. I'm confused, can an expert please give me a definitive answer, thanks!

[bazza3004]

Hi i could be wrong but think the wider one can be used . Not sure if i read something regarding omitting a spacer thats used with the smaller bearing. I could be wrong on this though.

Sorry that wasnt the definitive answer you were after

[Wack]

I think you have your shoulders mixed up The 150 crank has the wider shoulder (14mm) and the narrow 205 bearing, the 200 is narrower(10mm) to allow the 2205 to fit.The 150 crank can be machined to take the NU 2205 , omitting the mag spacer only allows the 2205 to fit the mag housing.

[bazza3004]

I thought it was something to do with the spacer. Should have realised really as ive not long since rebuilt my own.

[TurboTrev]

^^^ Thanks for your replies, although I'm not sure we have a definitive answer yet?

[HxPaul]

All GP 150s use the NU205 bearing and the spacer ring,UNLESS the crank has been changed for a GP 200 type with a thicker taper.This crank uses the NU2205 bearing without the spacer.

[TurboTrev]

All GP 150s use the NU205 bearing and the spacer ring,UNLESS the crank has been changed for a GP 200 type with a thicker taper.This crank uses the NU2205 bearing without the spacer.

Thanks, that answers it and it ties in with what Wack said above.

[Dimitrios_231]

Two great pics taken from Beedspeed site.

The later GP150 as Wack said,has the fatter taper like GP200 but the flywheel seal shoulder is 13mm like the Li/SX/TV cranks.
the earlier GP150 also differ with later in the crankpin size and shape.



This is the GP200 crankshaft with the 10mm flywheel seal shoulder.