gt 750 wont start

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chrispyduck
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Location: Shrewsbury

gt 750 wont start

Post by chrispyduck »

Very basic mechanic here wanting some help.
Whilst out riding on my GT750b i ran onto reserve near home however by mistake i turned it to Prime. Parked in the garage for a week i noticed a puddle of oil on the floor........now i reckon this is fuel and oil.

Okay so now the tap is on Reserve position with more fuel in the tank...........but the bike refuses to start.

I tried the tap in Prime position again but fuel run downs outside right exhaust. I checked the carbs and it is not coming from them. So now back onto Reserve position to prevent any further fuel flow and taken the plugs out and turned over the engine a few times to allow evaporation

Question is am i doing the right thing and would the flooded engine be the cause of the non starting?

Many thanks in advance.
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Waterbuffalo
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Re: gt 750 wont start

Post by Waterbuffalo »

Its best you start by removing the spark plugs and then the SRIS valves. SRIS valve removal will tell you how flooded the crank area is.
Two strokes, its just that simple.
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Alan H
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Re: gt 750 wont start

Post by Alan H »

Put a towel or paper towel(s) over the cylinder head - plugs out - and spin the engine over 'a lot' after you've done what Allan has suggested. Then when it stops spitting, plugs in and give it a try. Do it outside as the exhaust may be full of petrol oil mix! Or drain the exhausts as well.
Oh and it'ss smoke when it does start, boy will it smoke. Don't ask how I know that.
You may be ready for a carb service by the sounds of it too.....
Proof that four strokes are over complicated
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chrispyduck
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Re: gt 750 wont start

Post by chrispyduck »

I turned it over with the plugs out and no 'spitting' !
I am in not hurry should i leave it for a a few days with plugs out?
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chrispyduck
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Re: gt 750 wont start

Post by chrispyduck »

Plugs back in and it fired briefly but now nothing. The plugs were wet when i checked them but perhaps not enough. I am suspecting a fuel flow problem. The tap is working and i left it on Prime as i was trying to start it so there is fuel going somewhere?

Plugs are new and sparking. Any advice on what next to check...........it doesn't as first appeared to be flooded. :shock:
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martyducati

Re: gt 750 wont start

Post by martyducati »

Try all of the above again BUT when trying to start it leave the fuel tap in the ON position when the motor catches it will create the vacume to open the tap and supply the fuel that's needed,was the bike running well before this happened?
Cheers Marty!
barney01
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Re: gt 750 wont start

Post by barney01 »

Firstly i advise you to stop trying to start the bike. If it has been left on prime for a length of time the fuel will have continued to flow and filled the crankcase which is not good. If you try to start the bike it may snap or bend a conrod by a condition called 'hydraulic Lock' the mixture fires the piston downward but because its full of fuel and there is nowhere for it to go. Bang! The only answer is to make sure the crankcases are drained like Allan says is to remove the SRIS valves and leave them out overnight. Even if the crancases are not full petrol will be sloshing about soaking your plugs and preventing the spark. Of course too much petrol will wash oil from the cylinder walls too.
NO SMOKE .......NO POKE
timmo
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Re: gt 750 wont start

Post by timmo »

Did the same thing a while ago and asked here what to do. Take out sump plug and drain oil out,leave it a day. Fresh oil and dried out plug. Lucky you did not get it started or engine ruined or ball of flame with sump full of petrol.
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chrispyduck
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Re: gt 750 wont start

Post by chrispyduck »

Tried the fuel tap in the ON position. It does fire momentarily on the left. The plugs are sparking and wet but not too wet from petrol. It was running fine before now.
I understand hydraulic lock an took the plugs out in the first instance. It does not appear to be flooded.
barney01
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Re: gt 750 wont start

Post by barney01 »

Taking out the spa rk plugs will not prevent hydraulic lock. Its the SRIS valves at the bottom front of crankcase that will drain all the excess petrol/oil. One more thing to check being as you went onto reserve check the tap is not blocked with sediment by removing the bowl and mesh filter. Another way to test the tap is to pull off the vacuum pipe from the centre carb and the fuel pipe. Gently suck on the vac pipe and fuel should come out fuel pipe.
NO SMOKE .......NO POKE
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