Hello experts.....

Coudl someone explain to me in detail what the little channel between the carb intake and the frontside bearing is for besides lubricating it?
I "heart" a story which says something about pressure balance etc...
Reason i'm asking is I want to know the truth about whether a crankcase cap on the front is actually helping keeping out unwanted air through the frontside bearing making the tune more easy or at least widen the tune bandwidth a bit.
The only thing i can imagine is that when the crank is passing bdc the piston starts sucking in the mixture and to prevent unwanted air through the bearing due to the lower pressure at that particular moment it sucks a tiny bit through this channel making sure no dirt is sucking in.

I don't know whether this al makes sense or not as Im a newbie at nitro engines learning every day...

cheers

w.

Yes, with pressure differences it prevents oil spitting out of the front bearing. The cap is to prevent that dirt is pushed/sucked into the bearing but that is mainly an offroad issue. With onroad engines there is no need for a dust cap over the front bearing.

Normally with or w/o it should not give any tuning advantages, the crankshaft is surrounded with oil working as a seal as also the groove in the crankshaft and crank case close to the front bearing is working as a seal (and there is the small chanel for to make it work)

You can get tuning issues when the bearing gets play, then the gap at one side of the shaft is getting too large so the system of pressure and oil is not working anymore.