Britbike forum Forums British Motorcycle specific Brands Royal enfield forum 1955 350 Bullet Primary Drive

Am I right in thinking that the hole in the rear of the primary chain case is just for filling and the smaller 5/16” hole in the bottom of the chain case is the oil level? On the Hitchcocks online parts book the larger plug at the rear is described as Drain/Filler plug. How can it be both? There are only two plugs in my 1955 chain case, the larger one at the rear and the smaller one at the bottom. Logic would suggest that the lower one is the drain plug but in the Hitchcocks parts book it is described as the level plug? I can’t find anything in the workshop manual that describes how to fill the primary chain case to the correct level, or how much oil to put in there. Hitchcocks also state that they use and recommend ATF in the primary chain case. Does anyone have any advice on this please?

Thanks,

Kev

i think
1955 was before radical ideas like drain plugs were common ... and Royal Enfield never adopted a drain plug .
plus the cover has to come off to adjust the primary chain . ( which might be the same interval as oil changes )
... you just pull or at least loosen the cover )
... and the primary will vomit its contents .
( to somewhat contain the mess , cover whatever frame or foot peg-bits that may get dripped-on , with plastic beforehand )

the back plug is the "fill to" level .
( I suppose you could stick a siphon into "fill hole" and extract some of the oil )
... or pull a wheelie ?

The hole at the back is filler/level. The small hole underneath, just forward of the footrest is drain.

ATF is commonly recommended for chain cases.
Its oily, but doesn't cause clutches to slip.
Magic stuff ?

i use aluminum foil to cover stuff and also to make a directional trough to run the mess into the pan . helps with the centerstand too