Smoke from crankcase breather

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lozza
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My Bike: zxr 400 h1

Smoke from crankcase breather

Post by lozza »

Was trying to find out why my H1 wouldnt idle well and ran lumpy, I seem to have fixed it by removing the crankcase breather from the airbox.
The breather is leaking smoke. this can't be normal?
I'm gonna get the compression tester out but I'm just really hoping that someone can tell me something else (a bit simpler to fix!) that could cause this???

got a vid here, starting from hot. sorry its the wrong way up but you get the idea!!
http://www.youtube.com/watch?v=BhH1GuWR ... e=youtu.be

before I picked it up the bike hadn't been used only started periodically for 2 years , but before he stopped riding he put in new oil, filter, head gasket and did valve clearances.
Its got 40,000 km on the clock so knocking on a bit...

any advice is much appreciated.
lozza
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Re: Smoke from crankcase breather

Post by lozza »

I've set the idle with the breather detatched and it ticks over much better now...
If i attach the breather when its smoking (smoke starts as it approaches operating temp) the revs surge from the 1200 it was idling at and it sits at 4000 rpm!!?? I'm stumped?
ross46
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Re: Smoke from crankcase breather

Post by ross46 »

Wouldn't it be the smoke from the breather entering into the airbox and then with the mixture ad it goes through the carbs
lozza
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Re: Smoke from crankcase breather

Post by lozza »

130 psi in cylinder 1 and 150 in the rest.
Caught some of the smoke in a bottle and put a match to it and it went up, must be petrol in it... :(

you reckon 130 psi is low enough to indicate serious blow by?

oil level is much higher than it should be. but wouldn't of thought that blow by would cause that as the petrol would be vaporized???
adamm1704
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Re: Smoke from crankcase breather

Post by adamm1704 »

The usable range for the zxr's in terms of compression is 99-156 psi so all of your cylinders are fine. you say that the oil level is too high. the smoke could be burning oil as you say it only smokes when its up to temperature meaning it would be hot enough to burn the oil? Having too much oil in an engine can be just as bad for it as not enough. if i was you in drain it all and put the correct amount in there.
lozza
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Re: Smoke from crankcase breather

Post by lozza »

adamm1704 wrote:The usable range for the zxr's in terms of compression is 99-156 psi so all of your cylinders are fine. you say that the oil level is too high. the smoke could be burning oil as you say it only smokes when its up to temperature meaning it would be hot enough to burn the oil? Having too much oil in an engine can be just as bad for it as not enough. if i was you in drain it all and put the correct amount in there.
Yup its my next move, but i wouldn't of thought oil fumes would burn???
ross46
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Re: Smoke from crankcase breather

Post by ross46 »

what from inside the engine? Can happen, minimal on road bikes but when you set your zxr up for racing they say increased oil consumption is normal, and are you sure its not just water vapour?, im intrigued what mine will do now so im going to take the hose off, and if you want people replace that pipe with a little pod filter
lozza
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Re: Smoke from crankcase breather

Post by lozza »

ross46 wrote:what from inside the engine? Can happen, minimal on road bikes but when you set your zxr up for racing they say increased oil consumption is normal, and are you sure its not just water vapour?, im intrigued what mine will do now so im going to take the hose off, and if you want people replace that pipe with a little pod filter
I caught some of the fumes in a bottle and put a match to it and it caught fire...
So I reckon either oil fumes burn, or i have petrol in there.

Explains why my revs jump up so high when i attach it to the airbox...
ross46
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Re: Smoke from crankcase breather

Post by ross46 »

Hmmm, im not sure, best person on this one would be banner as he will be better as its organic chemistry, either way you've got some form of hydrocarbon, might be petrol fumes but it might also just be from the breakdown of oil
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noelb
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Re: Smoke from crankcase breather

Post by noelb »

Oil level high + Sat up for years + smell of petrol from breather fumes = sticky float valve at some stage letting petrol into a cylinder and past the rings into the sump. Change your oil and try again.
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RedexRobB
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Re: Smoke from crankcase breather

Post by RedexRobB »

Im sure anything in vapour form is much more combustible, especially oil.
lozza
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Re: Smoke from crankcase breather

Post by lozza »

Changed it today and seemed to fix the problem :)

Drained 3.4 litres out...
ross46
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Re: Smoke from crankcase breather

Post by ross46 »

Oooh, that's not right... Wasn't milky or anything was it?
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