Possibly a daft RD200DX cylinder/barrel question.

[Gr8uncleal]

The cylinders for the RD200DX are different (and a lot heavier!) than those for the previous models.

The part numbers for the first DX models start 1E8, and I have a load of cylinders with 1E8 cast into the outside of them. So far, so good!

The part numbers for the later DX models start 2R7 and I was wondering if anyone knows, or can check their own bike, if these cylinders had 2R7 cast into them. Surely Mr Yamaha wouldn't have kept 1E8 cast into a 2R7 part number, would they..............?!

I couldn't see any photos on CMSNL or fleabay that might have helped.

Thanks.

[Alistair64]

The 2R7 barrels still have 1E8 engraved on them for sure.
The part number changed according to the year, around 1978/9, but I don't know what the differences were regarding the barrels/heads.
It's possible that the porting and compression ratio were identical, but the 1E8 cylinders and heads were matt black, whereas the 2R7's were partly polished.

[Gr8uncleal]

Thanks Alistair, much appreciated.