Suzuki RM100 engine number question.

[John Orchard]

I have a set of crankcases with the engine number RM100-101710, according the various lists about, that number on the cases is for an RM100A (piston-port only) BUT these cases are for a case/reed engine, I always thought the RM100A was debored (to 50mm) RM125M style?

Now to add to the mystery, the cylinder that came with the crankcase, has the piston/crankcase reed induction (as per the B model) BUT it also takes a full head gasket as per the RM100A, not the copper ring as per the B model !

Any advice welcomed.

EDIT: After closer inspection, it looks like it may be a '79/'80 cylinder but the engine number still does not check out :-I

[pokey]

The Suzuki ID charts are good and accurate but not exact. Throw the US numbering system into the mix and things start to get foggy as in 76 the US started using several state and company based forms of VIN and just to make it more fun, suzuki bikes americans identify as one year are often identified as the previous year model by the rest of the world and some canadian and UK models went via the US.

The exact reason for erroneous year ID i am unsure of though I suspect its due to the new company Suzuki created in 76 called  Suzuki Motor USA and its records being tardy or when they were reported to government authorities. These numbers and US VINs didnt get to match with the rest of the world till 78 product models when an International VIN system was introduced.. Thankfully most of the charts use AU or canadian data but again not perfect. Ive never found any Suzuki japan ID charts.

Yes your number translates by the charts to a 75A but seeing as it has the case reed its likely a 76B and possibly imported from the US. New model suzuki all start with the suffix 100001 which makes 101710 a relatively early number so its logical to think the number was allocated to Suzuki Motor USA its largest market but when the actual bike arrived is anyones guess.

if you check https://www.suzukipartshouse.com/oemparts/l/suz/50d380ebf8700229982f11cc/1976-rm100-parts which is also Babbits , a US website. You will see both A & B models listed for 76.
Confusing but hopefully you have a little insight into what you have.

[monaro308]

Old post but my old parts bike RM100 N/T (can't remember)engine number was 100160. The cases have both the RM100 and RM125T piston stroke cast just above the c/shaft sprocket.