Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet with the UCE engine => Topic started by: Rusty on August 16, 2010, 03:43:44 pm

Title: Crankcase Pressure
Post by: Rusty on August 16, 2010, 03:43:44 pm

I did an oil change yesterday and forgot to refit the oil filler cap before starting the bike. It ran ok but what was surprising was the amount of crankcase pressure being vented from the oil filler hole, it was quite difficult to refit the cap with the engine running.

I traced the ‘proper’ breather from the R/H crankcase just behind the oil filler cap back to the airbox expecting there to be a similar level of venting (oil filer cap on and engine running) but it was hardly noticeable.

Strange that the crankcase breather doesn’t release as much pressure as the oil filler hole. Is this normal? Nothing seems wrong with the engine.

Title: Re: Crankcase Pressure
Post by: Sub on August 16, 2010, 04:54:37 pm

Mine pushes out quite a bit of air in the airbox. I think what you're sensing there is just physics - a larger opening will have less restriction and push more air out.