Doing my first mods snorkle,k/n dynojet kit moffler mod.?the big hole on the back side of air with hose which looks like it goes into crankcase. Any way I covered it with duct tape. Made the changes put it back together and ran it . It really lost power , changed needles / jets nothing. went back at air box and seen the tape over the hole and removed it I have not road it yet but the engine shure did rev better.?was this my problem for poor performance? Ride safe steve

 

Don't do that! your Pressureizing the crank case! you will blow oil out every Where! if you want power it has to have vent to the pulse, of the intake cycle for a balanced system to keep oil off the crankem shaft and rods a slinging up that oil and draggin on the crank not good ,will slow you down and blow seals out.IMO JH.

 

yep, I agree... I have a slightly different problem, but the results worked good for me... alot of guys with the big bore kits, & the cams, that allow the engine to rev up to the rev limit, have expirienced oil blowing out of the crankcase vent, & into the filterbox, often, getting sucked into the carbs... I plugged the hole at the bottom of the filter box, & cut off about 4" of the hose, coming from the crankcase, ( to remove the last few bends in it ), & cut a section of 1/2" X 3' of flexible copper waterline ( I had it laying around ), & bent & routed it up by the handlebars, where the other vent lines run...

Is there a reason why you blocked off the crank case vent, in the 1st place ??? or are we misunderstanding what you did ???

 

I put the tape on so I would not nock the 8 little screws from air box done it just for got to take it off.

 

Im thinking of running my crank vent to my exhaust pipe with a moroso pulse valve like we used to do in the header collector of our pulling trucks this does make some extra power also , 100 o/o crank case evacuation. JH