Hey all. Looking to replace a source coil for a '75 DT250.
Ive found one or two with the exact part number. Both with really big price tags. Ive found several for a fraction of the cost in which the 1st three digits are slightly different but the rest are right on.
Ive been told that the 1st three digits in these part #s are of no consequence but Im not convinced of that. Anyone know if thats true?
Looking for source coil #438-81312-20-00
Have found many with everything matching BUT the 438. Anyone know if it would work?
Thanks!

On the contrary, the first three digits are of the MOST consequence! They identify which model it was first fitted to, although a number of models thereafter might use the same part (use Partzilla or CMSNL to see which models shared a part).

I would expect the next five characters in the part number to be identical for any coil. By and large, where a part number had a three character five character sequence, the five part was the same for any part. If you check out coils, speedos, tachos, fenders etc etc, you should see that the five character part is the same, regardless of model.

The above doesn't apply to part numbers that are five character five character, but they can also be "read".

Alan is spot on. First three are model code that the part fits (extremely critical)... second five is the type of part... the "-20" generally means a revision or two has been made.

There is an article in the Tech Library on deciphering part numbers or many of the earlier Service Manuals have a section on the numbering system.

Whilst sourcing generator parts for my UK model RD400 (which is where I'm located), I came across an article that indicated that -10 indicates a Hitachi electrical part and -20 indicates Mitsubishi. Does this tie in with the make of coil for your bike?

Mark is certainly correct in -01, -02 etc being part revisions (has anyone ever seen a -03 revision?).

DEET could rebuild the old one, and make it brand new again . PM him.

Is this for me or the original poster Rick?

If for me, I should be all sorted now, thanks. It looks like my problem was a severed wire in the rotor. I might be able to have it repaired, but I've picked up a spare anyway, just in case. European RD400s used Hitachi components, the US ones used Mitsubishi.

Was for Charles but if anybody has problems ( like yours Alan, or any related Stator issues, contact DEET ! )
Glad you got it sussed.
DEET is a wizard on that subject.

I've found one MAJOR problem with DEET...................he's on the wrong side of the Atlantic!!

Atlantic?
I've been flying to the UK across the Pacific!
No wonder it takes longer!