Bike is smoking. Needs help Quiting

[Bionic]

Hey Guys. Hoping you can have a few guesses whey my 1995 zxr750 is smoking. I ll give the full story.

I started my bike up as usual to go ride to work. Let it idle and warm up while I get my gear on.
I rode around 1 km away from home stoped at a set of lights and the bike is smoking like a Mofo. Grey Smoke from the Exhasut. Bike doesn't seem to have lost any power or anything.

It starts first kick without any issues and it doesn't start to smoke until 3 to 4 minutes while idling.
THe longer the bike runs the more it smokes.

1st thing I thought was the Crank case breither was blocked or somthing. I checked that and it seems fine. I can start the bike up while the 1 way valve is off and just venting to tha atmosphere. I can feel a very slight amount of air coming from the hose.

How much blow by \ PResure should I be getting?

Haven't checked the spark plugs to see if there is any Black oily plugs.
Few things I think I have rulled out

- I would have thought if the valve stem seals were shot it would smoke heaps on start up,
- If the oil rings were shot I would think it would smoke straight away
- If the compresion Rings were warn I should have been getting alot more blow by than what I was getting.
- There is no WAter in the oil and there is no Oil in the water so im guessing the head gasket is fine


Any ideas guys?? The bike has 75000kms

[Rossi]

Sounds like a head gasket to me mate cos
white smoke generally indicates water getting into the block BUT
with the cold weather we have been having it could just be condensation thats collectedin the exhaust pipes .....there should be a small drain hole in the pipe/collector box area, check that's clear first

[Bionic]

Yeah but its GREY smoke. and it is Oil smelling. And it hangs in the air heaps like oil smoke. It doesn't disperse fast like steam

[Rossi]

basically answered your own question .........
get the tank off and out with the compression tester young man

[chameleon]

If it gets smokier as it warms up it sounds like oil leaking into one of the pots from the head alright, because as the oil get hotter, and thinner, more will get pushed/sucked through. Or depending on ya model, from the rocker cover where it mates with the spark plug holes but that would only be a little oil weeping past the plug. Doubt if it's an oil ring cracked because that would cause smoke to piss out right from go. Sounds like a head issue alright, Take the rocker cover off and check the tension on the bolts, you may get lucky

[Bionic]

Thanks Chameleon.. Yeah I was thinking it had something to do with the head or crank case presure..

Ill start pulling it apart over the next few weeks and take the head of anyways. Gives me an excuse to replace the cam chain and clean up the ports a little

[mrmina]

nicorette nicorette nicorette , u can beat the smokey bike.

not as catchy as the add

[Bionic]

THanks for you help everyone. Im in the process of taking the motor out.
Stuffed head gasket was the cause..

[jpbikeboy]

You said you might change the cam chain while you were there. I don't know if you realize that you have to split the crankcases to do that on your model. Not an easy job. I reckon it's a design fault, but what can we do about it.

[chameleon]

Can't you just cut the chain with a grinder and then "feed" the new one through on the end of the old?

We used to do this back in the stoneage with our rockbikes

[FrogZ]

Can't you just cut the chain with a grinder and then "feed" the new one through on the end of the old?

We used to do this back in the stoneage with our rockbikes

You mean there is ANOTHER way to do it