Please help!

[Poohbear88]

OK so I bought my fazer about a month ago... Lovely bike to ride and I was over the moon with it.... Then all of a sudden 2 days ago the bike started to jitter/stutter like it wants to stall... Ive narrowed it down and this only happens when the bike is warm and under hard acceleration... Any ideas!?

[slappy]

TPS faulty would be my guess.

[His Dudeness]

if it was fine and then all of a sudden had a problem that'd most likely point to an electrical problem. tps seems to fail quite a bit as slappy said. might be the regulator rectifier getting hot. you could measure the voltage going to the battery when the bike is hot to give you an idea if that's working. or it could be a problem with the alternator. you could check the resistance of that and the voltage it putting out when that's hot. you could have a look at your air filter too. it's unlikely to be the problem if it only happens when hot but worth a check. if it's blocked it'll cause problems with hard acceleration

[darrsi]

I'd consider lopping 5mm off the end of the HT leads then screwing the spark plug caps back on really tightly for starters.
There are several things it might be, but you've just gotta go through a process of elimination.

[daviee]

what kind of revs are you  nailing it at mine done that when i first got it if you gave it too much throttle under about  5 grand it would cut onto 3 what i  done was put good  fuel system cleaner in the tank and that fixed it completely  it was water in the carbs that would sit at thee bottom of the float bolls and when you give  it some the suction from the jets would lift the water   and block the jets, fuel system cleaner emulsifies water so that it can be sucked through the jets worth a try for the sake of a £10

[bandit]

Check your spark plugs.

[JoeyMcEssex]

also could be fuel pump related, at full whack could be under fuelling?

[darrsi]

also could be fuel pump related, at full whack could be under fuelling?

Or kinked pipe under the tank, or fuel tap not fully switched on.

[Gnasher]

Ive narrowed it down and this only happens when the bike is warm and under hard acceleration... Any ideas!?

What was the weather like that morning cold and damp by any chance?

[darrsi]

Ive narrowed it down and this only happens when the bike is warm and under hard acceleration... Any ideas!?

What was the weather like that morning cold and damp by any chance?

You're hinting at carb icing, and/or a blocked carb heater circuit pipe?

[Gnasher]

Ive narrowed it down and this only happens when the bike is warm and under hard acceleration... Any ideas!?

What was the weather like that morning cold and damp by any chance?

You're hinting at carb icing, and/or a blocked carb heater circuit pipe?

Yep

[darrsi]

Ive narrowed it down and this only happens when the bike is warm and under hard acceleration... Any ideas!?

What was the weather like that morning cold and damp by any chance?

You're hinting at carb icing, and/or a blocked carb heater circuit pipe?

Yep

Mine had that when i first got the bike, best description is "just about ticks over like a poor running tractor" 

[Jamieg285]

I can't see it being carb-icing in May.  I've had it a few times and only ever when air temp is properly cold.

I doubt it's a fuel feed problem (so not pump or pipes) as the problem is immediate when you open the throttle. Supply problems would show symptoms a bit later, when the fuel bowls have emptied where the re-fil is too slow to keep up.

IMO it's electrical - check plugs, wires, TPS, maybe coils.    What revs/gear are you in when it happens?

[Gnasher]

I can't see it being carb-icing in May.

The post was made in March matey 

[Jamieg285]

Hold on, I'll reply again in August 

[Gnasher]

Hold on, I'll reply again in August 

 

[tommyardin]

I'd consider lopping 5mm off the end of the HT leads then screwing the spark plug caps back on really tightly for starters.
There are several things it might be, but you've just gotta go through a process of elimination.

I'm with Darrsi, HT leads cost nothing to do, and, if it isn't them that's causing the trouble you have just stopped it being a problem a way down the line.
I did mine because i noticed it running just a little lumpy for the first 10 or 15 seconds after first starting and I noticed one downpipe was markedly cooler than the other 3, so, 5 or 6 mm off each lead HT caps screwed back on (How Hard to get them started to screw back on) and the problem was solved.
Other than that I have no suggestions, as I have not had any other running issues apart from multi connector boxes, but that is another story.
Good Luck
 

[midden]

if it was fine and then all of a sudden had a problem that'd most likely point to an electrical problem. tps seems to fail quite a bit as slappy said. might be the regulator rectifier getting hot. you could measure the voltage going to the battery when the bike is hot to give you an idea if that's working. or it could be a problem with the alternator. you could check the resistance of that and the voltage it putting out when that's hot. you could have a look at your air filter too. it's unlikely to be the problem if it only happens when hot but worth a check. if it's blocked it'll cause problems with hard acceleration

I would say air filter first (mine wouldn't accelerate passed 7k)  and then if problem isn't solved go down the plug and lead route (trimming couple mm of)