Just got back from my mates house. He asked me to come and look at his m/cycle, a ZXR750L as it wouldn`t start/turn over and he suspected starter
motor fault. Sure enough solenoid was clicking with power getting to starter so motor suspected as being knacked. Now picture this! I remove starter
motor and whoosh, fluid galore comes out of hole where starter motor was located, petrol/oil mixed fluid. Now that shouldn`t happen I said!
Thinking the engine may be `locked` with excess fluid I then removed the right hand engine cover to get at crank end nut so I can turn crank over.
Whoosh again! I have drained out of the engine (via this side cover) 8 litres of oil mixed heavily with petrol. The oil is as thin as water. The fuel
tank is also empty on the bike (It was a full tank!)
What can cause this major failure/loss of fuel from tank and how could it drain into the engine? I`ve had engines blow before with water in oil but
never petrol in oil. The engine still won`t turn on a spanner having now got the oil level down to normal so I`m suspecting a big failure
somewhere.
Any suggestions?
Nick
I had a gsxr that had a dodgy fuel tap (wouldn;t turn off) and carb, which meant if left connected it would fill the engine with petrol.
Hi this happens when a float sticks in a carb and the fuel siphons away into the engine past the rings and into the oil
the rings will be stuck to the cylinders rusted by the petrol pour some oil down the plugholes leave a while then bump the bike in 2nd gear to
freee the rings
engine should be ok after this
cheers malc
A common problem for carb'd bikes whose owners don't turn the fuel off!!
What Malc said really. Dodgy floats pouring fuel into the engine will be what did it. Mine did it once, but not for long enough for the fuel to get
past the rings. You could take the plugs out and get a 6 foot spray of fuel when you hit the starter!
I know the fuel tap was definately leaking as when in the `off` position, fuel was still running out! I`ll get that replaced and clean the carbs out
and hopefully its sorted then by the sounds of it.
Should I flush the engine through with some cheaper oil and a flushing agent once its all free and moving again?
As above, common problem on older Jap bikes. Less so on Brits as the carbs are rarely at a big enough angle to pour it into the head, just pours onto
the floor with the oil!
I think it wil be fine with once you run the oil through, then change it. Not that there is much "cheap " bike oil about
yikes glad I turned the fuel tap off on my old bike
Whatever you do, m8 - Remember safety first - petrol - and especially petrol vapour is HIGHLY inflammable - results could be surprising, or even
worse - 'hitting the starter' could be a very bad idea? - get it outside, and disconnect the battery.
Call me an old woman if you like ! :
When my VFR got fuel in the oil I did a cheap oil and filter flush for about a hundred miles first before fitting a decent oil and OE filter.
One thing that I had was that owing to fuel getting into the combustion chambers it had also flowed out the exhaust valves and sat in the lowest part
of the exhaust.
I had a shock when I started it and petrol started pouring out of a drain hole in the exhaust.
After dismantling the cat was FULL of petrol and could have been an issue!
Be careful
Geoff
quote:
Originally posted by stevegough
Whatever you do, m8 - Remember safety first - petrol - and especially petrol vapour is HIGHLY inflammable - results could be surprising, or even worse - 'hitting the starter' could be a very bad idea? - get it outside, and disconnect the battery.
Call me an old woman if you like ! :
As ever, thanks for all the advice so far. Fortunately his bike lives outside under a car port so its well vented anyway. There`s no cat fitted either
so that problems avoided but point taken there may still be fuel in the bottom of the downpipes!
I`ll try and get over there again over the easter break, remove the plugs and check the pots and check the carbs. Oh, and I`ll tell him to buy a new
fuel tap!
Nick
quote:
Originally posted by snippy
I`ll try and get over there again over the easter break, remove the plugs and check the pots and check the carbs.
Having spent a couple more hours at it this afternoon this is where I`m at. Drained another 4 plus litres out so all fluid now out (total of 12 1/2 litres!) Removed spark plugs, Cylinders 1 & 2 still had fair amount of fluid on top of piston, others are empty. Engine is free and will turn over on a spanner so thats a good start. Removed carbs and checked all 4 floats and needle valves. All 4 were very clean and moving freely so no blockages there. Starter motor has definatley had it, won`t work when shorted across car battery. So will fit a new starter, fuel tap, put it back together and see what happens.
Update - Have replaced starter motor and fuel tap and put it all back together with fresh oil & filters. Managed to get the bike started last
night but running very rough. Sounded as if flooding still so checked carbs again and carbs 2 & 4 were well flooded, fuel sloshing around inside,
again started leaking through to inlets. So, carbs removed and all excess fuel `soaked` up.
Does this suggest a sticking needle valve in those 2 carbs, debris in the needle valve seat or some sort of float problem? I`m gonna have to strip
them down again.
Nick
Yep, to me it sounds like any of the three you've mentioned.
Thought I`d update on what the problem was. None of the 3 things I guessed on 2 posts up! It turned out that the o rings that sit around the needle
valve guides themselves were perished and so even when the needle valve itself was closed, fuel was escaping around the outside of the guide past the
o ring into the bowls and flooding the engine. This only became evident when I blew through the fuel supply hose and saw bubbles around the valve
guides on the 2 problem carbs. Having now fitted 4 new o rings, the engine runs fine. Worth remebering if anyone else has this problem in the future.
Thanks again for all the helpful suggestions.
Nick