front cylinder misfire - SV650.org

Wideboy · 12-09-10, 03:34 PM

front cylinder keeps konking out and is getting progressively worse, gets more violent as bike comes up to "normal" temperature but over the last three rides it has got really bad.

checked it all over, got a healthy spark and everything works as its should but when out and about with the bike up to temperature the front cylinder starts cutting out with the loss of the rev tacho (so its and electrical problem?

). starts off as just sounding a little rough and when revs increased it goes, but after a while the cylinder cuts completely and you had to dip the clutch and give it an aggressive fist full to get it to kick back in. Tuesday night i did 35 miles on the motorway with a constant 7k revs for the whole 35 miles (late and road was clear) without fault but as soon as i came down the slip road and rolled off the throttle it started.

i cant see anyhting wrong so im thinking something electrical is brokeded, coil for the front perhaps??

p.s. no its not water in the front plug and yes i have changed the plugs

widepants · 12-09-10, 03:56 PM

gav..are u 100 percent sure its the front one,or is that another daft?

12-09-10, 04:13 PM

Fuel blockage?
The fact that a fistful stops it suggests fueling to me ???

Wideboy · 12-09-10, 04:15 PM

Quote:

Originally Posted by widepants

gav..are u 100 percent sure its the front one,or is that another daft?

well i burnt my finger on teh rear downpipe trying to find out so i'd say im 100% lol

Quote:

Originally Posted by specialone

Fuel blockage?
The fact that a fistful stops it suggests fueling to me ???

fuel blockage would be constant problem tho not intermittent? also i wouldnt have thought you would loose the rev tacho?

i duno im crap with electrics

12-09-10, 04:18 PM

Exactly whats happening with the tacho when you lose the one cylinder ?

Wideboy · 12-09-10, 04:19 PM

it goes straight to zero, not a slow gradient as the revs drop, just drops straight away to zero

fizzwheel · 12-09-10, 04:26 PM

Tacho IIRC takes its feed from the coil that runs one of the cylinders, I cant remember which one though. Sounds electrical to me, but I'm no expert where this is concerned.

Liz's SV is doing something similar, tried new plugs etc etc. Bought a 2nd hand coil off ebay in the end but never got around to fitting it, but thats where I'd start in your shoes.

Wideboy · 12-09-10, 04:27 PM

im pretty sure it runs off the front coil so unless theres a didgy connection id say it was fubard

12-09-10, 04:30 PM

It does sound like the coil mate, if the tacho is going to zero, each cyclinder has its own coil doesnt it?
Swap it over with the rear cycliner see if porblem transfers to the that one.

Wideboy · 12-09-10, 04:34 PM

aren't front and rears different?

12-09-10, 03:34 PM	#1
Wideboy Evel Knievel Mega Poster Join Date: Jun 2007 Location: Eastleigh Posts: 4,641	front cylinder misfire front cylinder keeps konking out and is getting progressively worse, gets more violent as bike comes up to "normal" temperature but over the last three rides it has got really bad. checked it all over, got a healthy spark and everything works as its should but when out and about with the bike up to temperature the front cylinder starts cutting out with the loss of the rev tacho (so its and electrical problem? ). starts off as just sounding a little rough and when revs increased it goes, but after a while the cylinder cuts completely and you had to dip the clutch and give it an aggressive fist full to get it to kick back in. Tuesday night i did 35 miles on the motorway with a constant 7k revs for the whole 35 miles (late and road was clear) without fault but as soon as i came down the slip road and rolled off the throttle it started. i cant see anyhting wrong so im thinking something electrical is brokeded, coil for the front perhaps?? p.s. no its not water in the front plug and yes i have changed the plugs __________________ 05 DRZ400E RIP hovis

12-09-10, 03:56 PM	#2
widepants Member Join Date: Aug 2009 Location: somerset Posts: 480	Re: front cylinder misfire gav..are u 100 percent sure its the front one,or is that another daft? __________________ http://forums.sv650.org/showpost.php...9&postcount=17 lol

12-09-10, 04:13 PM	#3
Specialone Guest Posts: n/a	Re: front cylinder misfire Fuel blockage? The fact that a fistful stops it suggests fueling to me ???

12-09-10, 04:18 PM	#5
Specialone Guest Posts: n/a	Re: front cylinder misfire Exactly whats happening with the tacho when you lose the one cylinder ?

12-09-10, 04:19 PM	#6
Wideboy Evel Knievel Mega Poster Join Date: Jun 2007 Location: Eastleigh Posts: 4,641	Re: front cylinder misfire it goes straight to zero, not a slow gradient as the revs drop, just drops straight away to zero __________________ 05 DRZ400E RIP hovis

12-09-10, 04:26 PM	#7
fizzwheel Super Moderator Mega Poster Join Date: Dec 2003 Location: Somerset Posts: 3,614	Re: front cylinder misfire Tacho IIRC takes its feed from the coil that runs one of the cylinders, I cant remember which one though. Sounds electrical to me, but I'm no expert where this is concerned. Liz's SV is doing something similar, tried new plugs etc etc. Bought a 2nd hand coil off ebay in the end but never got around to fitting it, but thats where I'd start in your shoes. __________________ Look Dave, I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over. K5 GSXR 750 Anniversary Edition

12-09-10, 04:27 PM	#8
Wideboy Evel Knievel Mega Poster Join Date: Jun 2007 Location: Eastleigh Posts: 4,641	Re: front cylinder misfire im pretty sure it runs off the front coil so unless theres a didgy connection id say it was fubard __________________ 05 DRZ400E RIP hovis

12-09-10, 04:30 PM	#9
Specialone Guest Posts: n/a	Re: front cylinder misfire It does sound like the coil mate, if the tacho is going to zero, each cyclinder has its own coil doesnt it? Swap it over with the rear cycliner see if porblem transfers to the that one.

12-09-10, 04:34 PM	#10
Wideboy Evel Knievel Mega Poster Join Date: Jun 2007 Location: Eastleigh Posts: 4,641	Re: front cylinder misfire aren't front and rears different? __________________ 05 DRZ400E RIP hovis

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