Crank Case Breather Hose Question

Doc Brown · #1 06-03-2020, 02:38 AM

On my 2019 300 EC I found two hoses near the cylinder. One on each side coming from the PV housings. They both were connected two the air box.

According to the race prep recommendations I removed them and plugged the hole in the intake rubber.

I always find a drop of oil coming from the left hose. Sometimes it is a bit thinner and obviously mixed with water sometimes it is pure oil.

I also had this on both other 300's I had but not as much as on my actual bike.

Bike is new (9 hrs) and runs very well otherwise. Compression is fine too.

Reason to worry?

PS I cross posted my question on TT Forums as well...

gasgasman · #2 06-03-2020, 06:25 AM

The left hose is the power valve chamber drain.
Some residue is normal.

The right side vent hose- pointing up- is the transmission vent.

Doc Brown · #3 06-03-2020, 09:37 AM

Quote:

Originally Posted by gasgasman

The left hose is the power valve chamber drain.
Some residue is normal.

The right side vent hose- pointing up- is the transmission vent.

Thank you GGman, could be due to the fact that I was running 40:1 the first tank for running in... So more oil than normal.

(F5) · #4 06-03-2020, 02:04 PM

Oil is good. 40:1 -is fine and brings benefits of reducing wear for little extra expense.

Doc Brown · #5 06-04-2020, 12:03 PM

I think we've once discussed oil ratios. I normally run 60:1 and even 80:1 and never had a problem.
Currently I run 50:1.

swazi_matt · #6 06-04-2020, 06:00 PM

Quote:

Originally Posted by Doc Brown

I think we've once discussed oil ratios. I normally run 60:1 and even 80:1 and never had a problem.
Currently I run 50:1.

I guess it depends a lot on what rpm's you spend most of your time at. The KTM tpi's vary the mixture quite heavily depending on the engine rpm or throttle
(and that is as far as i am getting into 2t mix discussion lol)

Doc Brown · #7 06-05-2020, 09:37 AM

Quote:

Originally Posted by swazi_matt

I guess it depends a lot on what rpm's you spend most of your time at. The KTM tpi's vary the mixture quite heavily depending on the engine rpm or throttle
(and that is as far as i am getting into 2t mix discussion lol)

That's true. I am mostly in the lower to mid range but on straight sections I let her rip from time to time. On the playground(s) I normally ride WOT in 5th and 6th is possible for about 5 seconds

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