The crank vent mod has been tried by many with varrying opinions on whether it was worth squat or not.

IMHO any "performance" increase was negligable if there was any at all but the possabiliy of oil getting into my airbox with a lydown or worse yet water getting into my airbox and finding an easy way into my crankcase bothered me.

Some have said if they had it to do again they wouldn't. What I did to "reverse" mine was to take a half inch felt polishing wheel for a dremel tool (available at any hardware store) and pushed it into the hole then took a heated screwdriver and melted a couple of very small ears at the opening to keep it there. It's a fairly snug fit though.

The felt polishing wheel has about the same size hole through the middle as the original airbox hole and the felt breaths a little bit as well but won't allow quick access to or from the crankcase by unwanted fluids.

There are probably a hundred ways to do it. The felt wheel just happened to be handing and fits like a tight glove.

 

That's odd!

 

Not odd in my opine....the crankcase mod was a waste....wish I never did it.

 

Here's what I'm talking about.



It has a hole already about the size of the original vent hole plus it breaths a little so the case gets as much or more venting but the felt and small hole won't let water or oil through nearly as quickly as an enlarged hole.

 

MY POV is from the 300R airbox perspective, that's what we get on our 250's. The hole in the airbox is the same as the hole in the crankcase. The factory put a rubber bung in the middle of the hose that connects the two to limit airflow. I removed it and felt an instant difference. If by "the mod" you are referring to routing the hose up by the seat and fitting a filter, then I concur, it's a waste of time.

 

just curious, why is running the hose to the top of the frame and putting a filter on it a waste of time? i did that and noticed a pretty big difference.

 

+1 on that. Its 100% fact. I noticed it as well.
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Granny *******

 

Oh, and an opinion on water from me. If your having water problems........well then you should, because this is a motorcycle, not a submarine. You want to run in the water, get a boat. You shouldn't have to do things to prevent water damage, other than simple sealings through standing washing and mud splatter.

One should not be fjording deep creeks on bikes, if you do do it at your own risk. Don't expect the machine to be that way from the factory. Espeically a bike thats meant to spend half of its time on the street.
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Magic flight launch box review

 

The key is opening up the vent. It's a free mod. Adding a snorkel has cost you time and money over the simple vent mod with no extra benefit IMHO.

 

The benefit of the filter under the seat is to keep dirt out of the crankcase...

And horizonod - that felt washer thing you show a picture of is WAY smaller than the stock vent hole, and it's FELT which will surely gum up with mud in no time.
(my air box gets plenty of mud and sludge in the bottom)

The stock hole in the airbox is maybe 1/4'' in stock form, and is a thin plastic collar, not likely to get gummed up - well not as easy as that felt would.