Modified LAMs bikes?

[avgas]

The simple answer is, the RD250 (air cooled) were NEVER manufactured with expansion chambers.... the 250LC was Yam's first 'factory expansion' The Suzuki X7 was the other 'factory expansion' OEM exhaust pipe.Possibly the younger Popo of today would not realise this, but I am sure there are plenty of 40+ popo out there who DO know the difference...
If the pipes are really loud, you could ge a pair of 'stingers' made and welded on, to reduce the crackle somewhat.

I think you missed my question.
Can you get OEM exhausts for RD250 that don't have the banana pipe expansion cambers.
i.e. straight through, same diameter header pipes.....like the good old days.

All the ones I have seen (as aftermarket spares) are no longer like that - but it could be just I haven't seen them. Most now come with a very slight expansion chamber where straight bent pipe would have been. (for the 250's anyway).

In saying that I have seen plenty of new 400's without the expansion chambers (and new pipes). So it could just be a choice of the 250 riders out there.

[GrayWolf]

I think you missed my question.
Can you get OEM exhausts for RD250 that don't have the banana pipe expansion cambers.
i.e. straight through, same diameter header pipes.....like the good old days.

All the ones I have seen (as aftermarket spares) are no longer like that - but it could be just I haven't seen them. Most now come with a very slight expansion chamber where straight bent pipe would have been. (for the 250's anyway).

In saying that I have seen plenty of new 400's without the expansion chambers (and new pipes). So it could just be a choice of the 250 riders out there.

Sorry missed this reply...
from dim distant memory....
I believe the RD250/350/400 OEM mufflers are identical, the only difference was the length of the downpipe (slightly longer) on the RD400 due to the longer stroke.
Another VERY viable option is the standard pipes from an RD250/350LC (non YPVS) I know these were used successfully on the air cooled bikes.
I had gone onto big 4 strokes before the arrival of the YPVS version, so have no real knowledge if they were 'good' on the air cooled bikes.