missing on a cylinder
12-24-2009, 06:26 PM
#1
Member
Squid
Thread Starter
Join Date: Dec 2009
Location: st pete, FLA
Posts: 64
missing on a cylinder
hey guys i m new to this site.. i just got a superhawk last errk and i love it.. how ever i am having a problem with it. at idle it missis up too 4 grand then it runs good to 7 where it will miss again. i have a k&n air filter and kurker ext. i cleaned the carbs with no improvement. i also checked my valves and it was all in spec. im thinking it may not be jetted right or carbs may need to be syncronised. it would help alot if i could get some tips
thanks guys
thanks guys
12-24-2009, 07:17 PM
#2
Senior Member
MotoGP
Join Date: Mar 2007
Location: Phoenix, AZ
Posts: 3,132
Welcome.
There have been a few people with this problem, and there are several possibilities:
The easiest one to check for is what we call PVLIR, that is petcock vacuum line inadvertent relocation. The small hose to the petcock goes on the rear of the petcock that points to the right, and not on the one on the bottom that looks like where it goes.
The next possibility is if this only happens in the rain, it is likely to be the tank vent hose because that needs to be rerouted from the stock location otherwise it gets plugged with water.
Also often when you get this symptom it is a bad coil.. They may even test fine and still act up this way, the only real way to tell is to swap them out and ride it.
If I have forgotten any (and I am sure I have) someone will chime in. This is not a common problem, but it has happened enough that these are the fixes I recall.
There have been a few people with this problem, and there are several possibilities:
The easiest one to check for is what we call PVLIR, that is petcock vacuum line inadvertent relocation. The small hose to the petcock goes on the rear of the petcock that points to the right, and not on the one on the bottom that looks like where it goes.
The next possibility is if this only happens in the rain, it is likely to be the tank vent hose because that needs to be rerouted from the stock location otherwise it gets plugged with water.
Also often when you get this symptom it is a bad coil.. They may even test fine and still act up this way, the only real way to tell is to swap them out and ride it.
If I have forgotten any (and I am sure I have) someone will chime in. This is not a common problem, but it has happened enough that these are the fixes I recall.
12-25-2009, 10:57 AM
#5
jet wrench
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Join Date: Jun 2007
Location: cowtown, CA
Posts: 175
As Lazn suggested, This is a rather common occurance on this bike, I have read of several instances as well as my own experience.
#1
The easiest one to check for is what we call PVLIR, that is petcock vacuum line inadvertent relocation. The small hose to the petcock goes on the rear of the petcock that points to the right, and not on the one on the bottom that looks like where it goes.
Additionally to this, you should disconnect the PVLIR line from the intake port fitting and apply vacuum(or suck on it using a CLEAR hose and see if fuel is leaking past the diaphram directly into your intake port. Which will foul your plug in a major way.
#2
Also often when you get this symptom it is a bad coil.. They may even test fine and still act up this way, the only real way to tell is to swap them out and ride it.
The sure fire way to check this, since it will ride virtually the same whether the front or rear cyl is not firing, (without buying an extra coil) swap coils from front to rear, rear to front... Having checked which cyl was cold prior to the swap, you can now determine if the "cold" cyl has swapped positions, following the bad coil.
I do this using a cheap screwdriver handle and touching the exhaust header about an inch from the port, you will notice a significant difference in which the handle will melt between the hot and "cold" not firing cyl, checking at diff RPMs will be necesary, depending on when your "missing"
Visually checking for a blue spark is no good! I had a consistant blue spark on the cold cyl, yet it failed to spark when under the cylinder pressure it experiences when installed in the eng.
These are the first, most important, and only steps you should address, until you are 100% satisfied they are ok.
#1
The easiest one to check for is what we call PVLIR, that is petcock vacuum line inadvertent relocation. The small hose to the petcock goes on the rear of the petcock that points to the right, and not on the one on the bottom that looks like where it goes.
Additionally to this, you should disconnect the PVLIR line from the intake port fitting and apply vacuum(or suck on it using a CLEAR hose and see if fuel is leaking past the diaphram directly into your intake port. Which will foul your plug in a major way.
#2
Also often when you get this symptom it is a bad coil.. They may even test fine and still act up this way, the only real way to tell is to swap them out and ride it.
The sure fire way to check this, since it will ride virtually the same whether the front or rear cyl is not firing, (without buying an extra coil) swap coils from front to rear, rear to front... Having checked which cyl was cold prior to the swap, you can now determine if the "cold" cyl has swapped positions, following the bad coil.
I do this using a cheap screwdriver handle and touching the exhaust header about an inch from the port, you will notice a significant difference in which the handle will melt between the hot and "cold" not firing cyl, checking at diff RPMs will be necesary, depending on when your "missing"
Visually checking for a blue spark is no good! I had a consistant blue spark on the cold cyl, yet it failed to spark when under the cylinder pressure it experiences when installed in the eng.
These are the first, most important, and only steps you should address, until you are 100% satisfied they are ok.
12-31-2009, 01:58 PM
#6
Member
Squid
Thread Starter
Join Date: Dec 2009
Location: st pete, FLA
Posts: 64
thanks guys
im at my buddys shop now i tested the petcok it tested good and i had the vacume line in the correct place im now going to check the coils. however the air filter it came with a k&n and i have no idea whats up with the jets if they were changed or not. nor do i have the stock filter. should i get a regular filter. and check the jet size. also im still waiting for the choke cable it broke off in the carb so i really need that untill i can really sync or anything like that.. i also saw that the airfilter has a gap im going to silicone after i change the choke cable.. one more question whats the stock jet size.. and what size should i use for the k&n and ext...
thanks guys helped out alot
thanks guys helped out alot
01-22-2010, 05:02 AM
#8
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Squid
Thread Starter
Join Date: Dec 2009
Location: st pete, FLA
Posts: 64
well the shop said they would take it back and fix it for me so i took it there and it was 3 weeks till i just worked on it my self. had it running so good in 9 hours fixed my coolent leak, my fan not coming on, oil leak, choke cable, swaped my coil. synked carbs.. and fixed air gaps.. now this is the bike i thought i bought.. the ony thing now is when its cold the carbs will sneeze on me.. any idea...
and thanks so much guys helped alot
and thanks so much guys helped alot
01-22-2010, 10:25 AM
#12
02-03-2010, 06:52 AM
#14
Member
Squid
Thread Starter
Join Date: Dec 2009
Location: st pete, FLA
Posts: 64
lol well my tps wires do have tape on them.. they were butt connected to a wire just chilling.. however some old *** lady opened her door on me in a gas station. broke my arm and all my fairings.. dumb bitch lol.. now i have a 20000 hospital bill. now i have to sue her..
02-03-2010, 07:58 AM
#15
Senior Member
MotoGP
Join Date: Mar 2007
Location: Phoenix, AZ
Posts: 3,132
lol well my tps wires do have tape on them.. they were butt connected to a wire just chilling.. however some old *** lady opened her door on me in a gas station. broke my arm and all my fairings.. dumb bitch lol.. now i have a 20000 hospital bill. now i have to sue her..
02-03-2010, 02:15 PM
#16
Senior Member
MotoGP
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
Did you learn anything about cars with people sitting in them?
Seriously sucks, but at least you're alive, huh.
I thought I was doing the prudent thing by positioing myself in the passenger mirror of a pick-up (just off to the side a hair)at a stop light instead of directly behind. Well, this guy decides to back up and let a car out from the gas station on his right. So he starts to back up slowly until I'm sitting tightly against his passenger's door trying to keep my SH from being forced to the ground. Honking my horn, shouting to no avail as his elderly wife evidently couldn't hear and had no peripheral vision because she sat there with her head straight ahead. I don't how i kept my foot from under his rear wheel as he backed up, but I know his truck was pushing me down. Anyway, after what seemed an eternity, I held the bike up with the right hand and smacked their door with the left. Finally, she looked over and jerked with fright and then slowly looked over toward her husband and got his attention. I was able to wiggle away forward but it must have been a funny sight to those watching. Anyway, I did learn something about positioning that day.
Seriously sucks, but at least you're alive, huh.
I thought I was doing the prudent thing by positioing myself in the passenger mirror of a pick-up (just off to the side a hair)at a stop light instead of directly behind. Well, this guy decides to back up and let a car out from the gas station on his right. So he starts to back up slowly until I'm sitting tightly against his passenger's door trying to keep my SH from being forced to the ground. Honking my horn, shouting to no avail as his elderly wife evidently couldn't hear and had no peripheral vision because she sat there with her head straight ahead. I don't how i kept my foot from under his rear wheel as he backed up, but I know his truck was pushing me down. Anyway, after what seemed an eternity, I held the bike up with the right hand and smacked their door with the left. Finally, she looked over and jerked with fright and then slowly looked over toward her husband and got his attention. I was able to wiggle away forward but it must have been a funny sight to those watching. Anyway, I did learn something about positioning that day.
Last edited by nath981; 02-03-2010 at 02:27 PM.
02-03-2010, 02:47 PM
#17
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Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
lol well my tps wires do have tape on them.. they were butt connected to a wire just chilling.. however some old *** lady opened her door on me in a gas station. broke my arm and all my fairings.. dumb bitch lol.. now i have a 20000 hospital bill. now i have to sue her..
02-09-2010, 01:24 PM
#18
Member
Squid
Thread Starter
Join Date: Dec 2009
Location: st pete, FLA
Posts: 64
lol thanks guys.. i hope i dont have to pay for all this ****.. it all add up. and nath your lucky. lol i just got all the parts to fix it just need to be able to move my fingers. there still swolen. any ways i got my broken parts fixed well in at least. also some new bt003 stoked to try those out on a track day. all i have to do now is fix my farings.. but i got my eye on the 11.5 pistons now.... lol
02-10-2010, 07:06 AM
#19
Junior Member
Squid
Join Date: Jul 2008
Posts: 25
coil replacement
I'm willing to bet some chicken that my issue is the petcock vent line misplacement, but what replacement coils are you folks using if that is the issue? I'm a lil "stir crazy" in here with all this damn snow! Any sec now, the power is gonna be out, cuz it's blowing sumthin fierce outside ! If I wanted this , I'd move to Canadia ! Thanx for the info,this site is a great resource ! Happy Shoveling !
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