Bike will not fire?

[Sauerkraut]

Hi guys,

I have a '92 Bandit 250 that I picked up a month or two ago. It has been absolutely brilliant since I bought it, always started first time and never any trouble. Over the last few days though it got a little more reluctant to get going 'til one morning I finally got it started and it was really struggling (idling at less than 1,000rpm) and then it just died. Battery was flat so I recharged it but now it still does not start at all.

So I've taken it to bits and so far:
Got spark
Got fuel
Battery's sweet
Starter is working fine

I haven't looked at the carbs because I don't know what to do with them. When I hold the starter down the bike will fire once or twice but not catch, and sometimes it sorta backfires (exhaust goes PAF and spits out a little puff of smoke).

Can anybody help me at all? I've reached the end of tenuous mechanical knowledge and it's really frustrating because the bike has never been difficult before. Something I'm missing?

Cheers!

[98tls]

When you try and start it can you smell fuel?as in its flooding.

[Sauerkraut]

Not as far as I can tell. No fuel smell plus I had drained the carb and had a squizz down into the engine when I pulled the sparks out. My dad reckons the backfiring might be a timing issue, which makes me nervous 'cause I don't actually even know what controls the timing on my bike.

[98tls]

Re timing,it was going fine then it wasnt,timing just doesnt go bad for no reason,Its either fuel or spark,possibly a sticking float,bad spark lead etc.Fwiw try starting it with the throttle wide open,if away it goes then its flooding.To be honest its hard to pin point over the web i guess.Have you got any spare plugs to try?

[Sauerkraut]

No spare plugs but the ones I've got look like they're almost ready to be replaced anyway, so I'm gonna go get some more. The ones that were in there were all mismatched anyway. I'll try with the throttle wide open.
How tough is a sticking float to sort out?

[Sauerkraut]

Just remembered as well that the bike had been running a little rough for a day or two before it stopped alltogether - difficulty in starting but accelerating very unevenly at times as well. If that helps diagnose at all!

[Hopeful Bastard]

Re timing,it was going fine then it wasnt,timing just doesnt go bad for no reason,Its either fuel or spark,possibly a sticking float,bad spark lead etc.Fwiw try starting it with the throttle wide open,if away it goes then its flooding.To be honest its hard to pin point over the web i guess.Have you got any spare plugs to try?

How would you fix this Flooding issue?

[CookMySock]

Full choke, try and start it normally.. spin it for 3-5 seconds, then stop. Smell the exhaust - any fuel smell?

If not, look under the carbs and find the drain screw and open it, and see if any fuel comes out. If not, check there is actually fuel in it. Pull the fuel hose off the tank and turn the tap on and see if fuel flows out freely.

Pull the tank off and find the fuel pump - the fuel line from the tank should go to it. It is probably operated by a vacuum line from one of the carbs, so pull this line off the carb end and also pull the fuel line from the pump going to the carbs, and suck on the vacuum line with your mouth - this should operate the fuel pump and squirt fuel out - if not, the fuel pump is stuffed.

Usually stuff like this is something simple, so dont panic and start thinking bad engine thoughts.

Steve

[kevfromcoro]

Hmmm interesting.. could be a number of things.
The bike was running rough a couple of days before hand..
It hasnt sucked a peice of the aircleaner into one of the intakes has it..?
Just a thought..............

[Logpot]

After reading many similar posts about bikes not starting or running rough the most likely causes are either bad fuel, a fuel blockage, bad spark or combination of all 3

[sinfull]

After reading many similar posts about bikes not starting or running rough the most likely causes are either bad fuel, a fuel blockage, bad spark or combination of all 3

I'd go with bad fuel/water in the tank ! Unless the air filter is that gunked up its finally said enough !

[98tls]

How would you fix this Flooding issue?

At this stage we dont know if it is flooding but if it turned out it was i would first look at a sticking float.

[Hopeful Bastard]

At this stage we dont know if it is flooding but if it turned out it was i would first look at a sticking float.

Ok. Sounds good.. Mine wont start with the choke on.. But it does start with a half open throttle.. Also had a nice backfire the other day.. Made me jump 6ft into the air! Seeing as i aint up on all the mecanicsm and aint no where a mechanic.. Is this a task that is easily do-able?

[Sauerkraut]

Air filter is OK. I suspected water in my fuel but I drained it out and let it sit for a while and there was no water in it.
Spark plugs and leads are OK and are sparking, just tested them.

When I try to start the bike I can't smell any fuel at all. So I'm starting to think it may be fuel supply problem. I'll try the fuel pump thing that DangerousBastard recommended!

[98tls]

Air filter is OK. I suspected water in my fuel but I drained it out and let it sit for a while and there was no water in it.
Spark plugs and leads are OK and are sparking, just tested them.

When I try to start the bike I can't smell any fuel at all. So I'm starting to think it may be fuel supply problem. I'll try the fuel pump thing that DangerousBastard recommended!

When you checked the plug was it wet?