I am aware that the suffix -10 means that the item is a Hitachi one and -20 means Mitsubishi. However, I have seen some parts with a -10 suffix that also have a -90 option (eg 123-45678-10 and 123-45678-90). Is anyone able to enlighten me on what the -90 means?

Also, I have seen some Hitachi parts with a suffix of -11 and some Mitsubishi with -21 - do these just mean that they are the first update of the original -10 and -20 part?

Many thanks.

I don't know that Yamaha was as structured, logical, and ordered as you want them to be. 

Just when you think you've figured out a pattern, exceptions seem to surface. 

If you had an exact example of a -90 it might help....

I know that -70 was used for the different ATMX hard parts like head, cylinder, piston, exhaust, shocks... 

Since you said they have -10 and -90 it might be one is genuine Hitachi and the other is another brand that will fit?

Thanks Mark.

An example is condenser part number 148-81126 and, according to CMSNL, it has suffixes of both -10 and -90.

My guess is -10 is OEM and -90 is an "aftermarket equivalent" replacement part?  I don't know for sure though.  If you can still buy both you could try it and see.

Like for a spark plug if Yamaha used an NGK spark plug at the factory it would be the OEM part and if they also listed a Champion spark plug it would be the aftermarket equivalent replacement part.

For example for a US model 1979 DT175F, to be "concours correct", you'd need to use a Champion N-3 spark plug as that is what came installed when new from the factory...  though now Yamaha only sells the NGK B8ES which "technically" would be an aftermarket equivalent replacement part.

 

Some of those suffixes denote variations that might go to different markets .
As Mark alluded to , -70 was a suffix that was used in GYT kit parts , in general .
With electrical especially , different markets had differing requirements to
satisfy local legislation . Wiring looms for example , A UK RD 400E is subtly
different to an Australasian market one . Headlights were another ,
different lenses for RHD and LHD markets , -61 and -60 respectively .
 

Just resurrecting this thread, as I have a specific query regarding my US import RD350.

The UK parts list shows the condenser as having a part number suffix of -20, but the suffix for the US is -90. Both market bikes use Mitsubishi generators (unlike the later RD400) and the suffix for the points for both models is -20.

Interestingly, CMSNL offer a non OE replacement for the -90 part, with one with a -20 suffix.

Basically, I'm looking to use a -20 condenser on my US bike, but looking for reassurance that I'm not going to a) jigger anything up and b) waste my money.

Thanks.