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Have any of you guys had this problem on the Y10 F4's ? I mean blowing oil into the airbox through the breather, when used on the track.
Obvioulsy not on my bike but on the bike that used to be raced over East and it's now in Perth.
I will suggest the guys look into a Leakdown test, and also waterpump seals, but that's all i have atm.
Thanks in advance for your help.
 

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Oil type too thin? ring seal poor? breather hose routed wrong? I got nothing....tell him to quit holding it a gear low on that short straight and go ahead and shift...or change final gearing so he doesn't have to over-rev when a change up is required but not efficient.
 

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Oil type too thin? ring seal poor? breather hose routed wrong? I got nothing....tell him to quit holding it a gear low on that short straight and go ahead and shift...or change final gearing so he doesn't have to over-rev when a change up is required but not efficient.
Oil is one thing in question Ed, I will have a look at the bike myself pretty soon and see if I can find something.
 

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Is he :f4: ????
 

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oiler?

pull the oil separator.....there is nothing in it :stickpoke

now put 2 stainless ChoreBoy pot scrubbers in it....I capped the airbox and put a PCV filter on the tube coming out of the separator:naughty:
 

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pull the oil separator.....there is nothing in it :stickpoke

now put 2 stainless ChoreBoy pot scrubbers in it....I capped the airbox and put a PCV filter on the tube coming out of the separator:naughty:
You've got a Y10 F4 - :yo:.
I have not had chance to look at the bike Noel, but from what I was told a similar patch was already in place, but not with much success.

I will see if I can figure out in the W/shop manual where the breather pipe comes out from on these motors.

Trying to figure out if this is a common problem on the new bikes, or a once of on this motor?
 

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Donsy:
l4 motors don't breath much......because the crankcase volume doesn't change much,
that said the crank isn't knife edged and it does not appear that the cases have an 'oil scraper' either
the reverse rotation crank will want to throw oil at the breather area
 

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Donsy:
l4 motors don't breath much......because the crankcase volume doesn't change much,
that said the crank isn't knife edged and it does not appear that the cases have an 'oil scraper' either
the reverse rotation crank will want to throw oil at the breather area
Thanks Noel. I was hoping someone else might have had the some problem on the new bikes, but not getting much back from anybody. It would be a bit sad if that fairley new motor was building up crank pressure for other more expensive reason's.
The guys seem to think the bike suck's the oil through when they shut the throttle from high rev's, the thinking is the breather in the airbox is close to #1 inlet trumpet, and this might cause enough suction to get the oil up there ?
 

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?

Donsy;
manifold vacuum is high when closing the throttles at high rpm......
but airfow in the airbox is about zero, the throttles are closed.

they didn't think about that one:naughty:
 

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Have any of you guys had this problem on the Y10 F4's ? I mean blowing oil into the airbox through the breather, when used on the track.
Obvioulsy not on my bike but on the bike that used to be raced over East and it's now in Perth.
I will suggest the guys look into a Leakdown test, and also waterpump seals, but that's all i have atm.
Thanks in advance for your help.

Yup common as muck, sustained high rpm and prolonged time at a set throttle will fill the air box with oil. The crank case pressure has to go somewhere. I did loads of stuff 8 years ago or more on ktm engines and sorting crank breathing due to removing the balance shaft which contained the breather pick up. Anyway, long story short. I put a breather in the side of the cam chain tunnel quite high up so in theory out of oil flow. After only a few minutes the oil had bled the air out of the breather and created a vacuum. I've never seen an engine actually empty itself of oil before but this one did. It was like a hoover mate, just started filling this massive tube I hade fitted and then into a catch tank. So not uncommon at all.

I notice it on th dyno mostly but I do see it in race bikes.

It's not just an MV issue, I be had all sorts do it so don't really worry about it.

Check oil level is slightly below max level and also the grade of oil. I use 15/50 as it wont get quite so viscious and hopefully not fill th air box.
 

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blowing oil?

Chris;
i don't agree, on a l4 or v8 there is no pressure added to the crankcase by piston movement.....by ring leakage there is

my Aprilia RSVR is a 60deg twin, it has a major percentage of 998cc change in crankcase volume each 360deg and it breathes through a horizontal 7.8mm hole in the rear intake cam, with a puddle of oil just inside:wtf:
but it only puts tablespoons into the airbox in 2,000mi, which i fixed:naughty:

when you remove the M24 plug in the stator cover, start the motor and hang a piece of paper 25mm from the hole it pulsates until ~4,500rpm when it stops moving.....the air stagnates
ZERO oil comes out!!!!!! not a single drop

under load a very slight mist comes out......the hole is right at the end of the crank with a ~22mm diameter so thats understandable.
i rerouted the breather with a 10mm ID tube to a ~40mm tube to slow it air down and filled the tube with, you got it, a Chore Boy pot scrubber:)
from the T, at the deliberate low spot in the line to the separator (Chore Boy) in the tail, i ran a line to the transmission/oil tank vent line......so any oil separated drains back into the transmission

my KTM 640 Duke ll doesn't breathe any oil and thats with a 625cc volume change every 360deg, its system works, so i didn't mess with it:stickpoke

you want to see a motor blow oil?

take a valve cover off a BMW 'oil head' boxer motor and hit the starter button
it throws oil 3-4 meters up a wall 2 meters from the bike......my buddy did it while i was standing next to the bike:jsm::jsm::jsm:
missed me though:)

that was 1,130cc of volume change, the stock separator breathes a lot into the airbox.....i haven't tinkered with it yet.....need to fix other stuff 1st

our endurance bikes did 3,000mi+ in 24 hours......exactly how much oil they used we didn't know.....they were topped off with a syringe, just like doing forks today

if your blowing oil with a l4 or 90deg motor (V8) you've got a blowby/breather location problem....

AA Top Fuelers making 1,000HP per piston don't puke oil......maybe they have better rings:)
 
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