Hey all so I have an 01 f4i that I recently resurrected from the dead, had about 23500 miles when I got it and were about to hit 25k since I got it tagged two weeks ago. After getting it running it idles at around 3k before going to 2.2-2k at very rare times it actually will go to 1.5k but after engaging in gear and moving then back to neutral it will always be 2.2. the other day while warming up it actually hit 5k and was screaming till it settled down. I can confirm it is not the idle adjustment as I have completely unscrewed it already (was not fun getting back in) Also when changing the oil after I first got it there was a fuel smell but after sitting so long paid no mind. ran it about 1500 miles and figured another oil change wont hurt. the oil was too dark too quick I think, and lost some of its viscosity and once again had a fuel smell. I think it might be a vacuum leak somewhere and a friend of mine was telling me if there it too much air from the intake it can lead to fuel in the oil?

Any tips/tricks in tracking down a vacuum leak or maybe some common offenders - or any other tips for fuel smell in oil would be appreciated.

 

fuel in the oil is a problem.
However it has most of the time to do with a leaking fuel injector.
Or at least not completely closing.
An idle of 2.2.k points in the same direction.

An easy way to check is to take the fuel rail out and put the key in position 2.
The fuelpump starts building pressure and if the injectors start to leak you have found your problem.
Normally this would be one of the few non-destructive ways to get fuel in de oil.
However really black oil might point to some excessive blow-by and thus engine wear.
With fuel in the oil that would not be very suprising, since fuel and oil mix well. But the lubricating properties are shared too.
Fuel has none, oil a lot. Together: whatever ratio of fuel and oil is used.

However if you bike does not smoke like a dutch weed junky then a vacuum line leak could definitly be a second problem.
However since you oil is quite black I suspect the bike smokes quite a bit.

Fuel pressure regulators are notorious to fail.
If fuel leaks out of the vaccuum line of the fuel pressure regulator then it is failed.
However then the fuel has to go a long way to the oil.
I think it is less likely the issue.

good luck

 

Awesome thank you for the reply. That gives me hope cause she in fact does not smoke at all, I believe I found the tube on the throttle bodies that could be a leak by spraying brake cleaner on it and she shot up to 3k. Im glad you told me about the injectors as I will check that as well cause with my luck it could be both.

 

I have an 01 CBR 600 F4i, recently bought. Fixed the Zener diode, new coils and plugs as well as fuel pump. Prime, sparks and fires, but if it doesn’t fire on the first crank or 3 the plugs get too much fuel on them. Fires but it gets too much fuel. The injectors shoot cones, steady, no dribbles. So I’m thinking I’m getting too much due to regulator being out? Any feedback is appreciated!

 

forgot to mention, when it runs it is not lean or rich. No excess fuel, or hesitation. Idles at 1,5k but only on start up does it foul out.