RM 250 / 370 A and B CDI units

[Nipper]

I need some help regarding CDI units for the A and B model 250 and 370 RM suzukis. I have a CDI box marked (from the Wrecker) RM 370,so i had a look at the suzuki parts books and seen whether it would suit an up coming project I am going to start. The numbers in the books say that the RM 250A and the RM 370A have the same CDI unit (32900 - 41110) and that the RM 250 B and the RM 370 B have the same CDI unit (32900 - 41111). Can I use this CDI unit on either A or B model 250 or 370 and hope that it will work just fine on either bkie / model ? Phew !

[JohnnyO]

I'm using a complete ignition from a 250 on my 370, like you said the 250 and 370 ignitions are the same part number.
I think it would be fine to run the cdi on either an A or B 250 or 370.

[Nipper]

Thanks Johnny O I will give it a try when the time comes and see what happens. Thanks.

[shelpi]

G'day  according to the july,1976 NEW MODEL TECHNICAL BULLETIN SUZUKI RM250B, RM370B
CDI unit assembly
Not interchangeable because of differance in ignition characteristics. (ie curve rateing for ignition advance will differ)

plus RM250B ignition time is 3.62mm BTDC
      RM370B "                "   4.15 mm BTDC

[suzuki27]

Thats interesting shelpi. I wonder what the difference is when riding. Did you notice any difference in the engine Johnnie?

[JohnnyO]

Thats interesting shelpi. I wonder what the difference is when riding. Did you notice any difference in the engine Johnnie?

No difference at all, it runs perfectly.
That 370 ignition timing quoted seems very advanced at 4.15mm BTDC

[shelpi]

lets face it technical data is one thing real world is another  all i know is when i assemble a engine the stator plate get firstly lined up with index mark on stator "C" TO THE CENTER OF SCREW INDEX MARK "D" then secure the stator plate wich is also a acceptable proceedure for assembleing if you have not got a timeing gauge, then when i use the timeing gauge (dial indicator) the timeing is out by 1.5 deg +or-
So considering all the variants you can be lucky or it can all go against you :'( so i choose the factory specs and so far no seized, hard to start, slugish and or flat spot engines but it has not stopped brand new plugs from failing 

[JohnnyO]

lets face it technical data is one thing real world is another  all i know is when i assemble a engine the stator plate get firstly lined up with index mark on stator "C" TO THE CENTER OF SCREW INDEX MARK "D" then secure the stator plate wich is also a acceptable proceedure for assembleing if you have not got a timeing gauge, then when i use the timeing gauge (dial indicator) the timeing is out by 1.5 deg +or-
So considering all the variants you can be lucky or it can all go against you :'( so i choose the factory specs and so far no seized, hard to start, slugish and or flat spot engines but it has not stopped brand new plugs from failing 

If you're fouling brand new plugs you might want to get your jetting right and also run 40:1 petrol/oil mixture.

[shelpi]

  ah yer, problem is i am a bastard for loading up new engine parts with oil and run them on 20:1 mineral oil for the run in then there is the honda generator one sparkplug lasted 10 years the next plug a brand new identicle NGK BPR6ES shat itself immiediatly like i said you can try to do all the right things but it wont stop the gremlins

[Freakshow]

i have a stack of BP6-7-8 plugs and was wondering what they fitted thanks.   

Some how i ended up with a fist full of protruding tip plugs, now i know where to start with them.

[shelpi]

Hey Freaky buy a MAZDA 808 and you will use those plugs by the quadro ah see i a meena 4ra