Moorron
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| posted on 21/8/06 at 12:18 PM |
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White smoke help!!!!!!!!
Right lads, after sealing the many leaks on my engine (except one water leak as I cant remove the pipe!), im still using oil which means its burning
it. This was confimed yesterday when I noticed blue/white smoke on overrun while I was reving it in a laybye trying to sort another problem. The
engine was still 'cold' so I am assuming when its hot u cant see this smoke as its being totally burned off in the exhaust?. Its not much,
but only seemed to happen when I lefted off the throttle and it smoked while the engine was returning to idle.
What is causing this? Is it valve gear or bottom end? Engine pulls hard and doesn’t smoke any other time.
It’s a 15 year old CBR1000FJ engined BEC.
If its an easy job (engine still in car) I will do it, but if not then its new engine time, maybe an R1. I take its not worth reconing the engine (I
have a spare) as it too costly. I am not prepaired to buy another CBR1000F 'running' engine as its going to be atleast 10 years old and
will be worn anyway.
Worth doing or not?
Thanks.
[Edited on 21/8/06 by Moorron]
Sorry about my spelling, im an engineer and only work in numbers.
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Coose
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| posted on 21/8/06 at 01:41 PM |
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I wouldn't worry - they all do that sir. It's just condensation.
Have a look at any four stroke bike starting from cold and you'll notice that they all do it. So long as it doesn't happen when the motor
is warm all will be well!
Plus, a bit of oil usage isn't unknown - Kawasaki says a litre per 1000 miles is normal!
Spin 'er off Well...
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ChrisGamlin
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| posted on 21/8/06 at 04:54 PM |
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Yep Id agree with Coose that you're probably seeing water vapour.
Also just for info, what you're describing isnt an "overrun" situation, the engine's only really on the overrun when the
wheels are forcing the engine to go faster than it would otherwise go, eg when off the throttle and rolling down a hill using the engine to slow the
car. In that situation you get lots of vacuum because the engine is still turning over quite quickly, but the thottle butterfly is closed so not
allowing much air into the cylinder. This vacuum sucks oil past the (worn) valve stem seals which you then see as a cloud of smoke when you next floor
the throttle and the oil gets burnt, but you're very unlikely to get enough vacuum when just revving it stationary to do that unless they were
extremely worn.
cheers
Chris
[Edited on 21/8/06 by ChrisGamlin]
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Moorron
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| posted on 21/8/06 at 07:23 PM |
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cheers, its not water vapour definatly oil. (the engine was warm, but oil pressure hadnt dropped when at idle, i know when it does its thinned out and
is warmed up to thrash)
WOW! i am suprised 1 litre per 1000 miles. However mine is going thru more than that (when i thrash it). thought it was all down to the various oil
leaks. but its almost bone dry now and its using it somehow.....?
Sorry about my spelling, im an engineer and only work in numbers.
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