rear cylider misfires

MUMMZ · 05-07-2007

I recently noticed that my rear cylinder is misfiring, pretty badly, the front is solid as a rock though. Does anyone have some hints on where to start looking?

OhioDrifter · 05-07-2007

Hi Mummz,

I had a rear misfire on mine, I swapped the plugs (front to rear, rear to front) as a test. When moved to the front cylinder, offending plug still would not fire. Changed both plugs and no problem since.

MUMMZ · 05-08-2007

Removed rear plug when I noticed the misfire, and it was very wet, changed out plug and noticed misfire again. Do they run off of separate coils?

Scruffy · 05-08-2007

Which bike? Most metric twins have one coil per plug, sounds like you have an 800 or 900 if it is single plug.

Go one heat range hotter on the rear plug. If you have an 800, that would be a CR6E instead of the stock CR7E. Not sure what the 900 takes plug-wise, haven't messed with one.

If it still fouls out and stumbles/misfires, get a mechanic to check it out.
-Scruffy

MUMMZ · 05-08-2007

Probably should have mentioned '02 Vulcan Classic 800. My concern is that it misfires badly at idle but drops off when cruising, unless at bottom end of gear. I don't think it has anything to do with mixture, but upon inspection of carb noticed had been rejetted, 162.5 for main and 48 for pilot, sounds right, but needle clip placement is on the second setting from top with two washers on top of clip ... wondering if that all adds up.

MUMMZ · 05-09-2007

Does anyone know what the fuel float setting is supposed to be for the aforementioned bike, if so how do you go about resetting it?

MUMMZ · 05-14-2007

Does anyone post answers to technical questions on this forum?

**2WheelFun** · 05-14-2007

The settings sound right.

Are you getting spark to the rear plug?

**2WheelFun** · 05-14-2007

In case you haven't seen this post.

http://www.kawasakimotorcycle.org/fo...djustment.html

MUMMZ · 05-15-2007

Yes I am getting spark to the rear plug, I found a loose connection in the spark plug wire so I put new wires on both. Also found another piece to the puzzle, at about 1/3 to 1/2 throttle (acceleration) the carb spits back into the air cleaner, after all I have done and all the things that I have checked I still find raw fuel in the air cleaner. I think it might be leaning towards a valve adjustment, and maybe some more tuning to the carb thanks for the link.

zedx11 · 06-03-2007

Quote:

Originally Posted by MUMMZ

Does anyone post answers to technical questions on this forum?

do you not have a shop close by? some problems need hands on bike in front of you to properly diagnose.

getting pushy don't help either.

zedx11 · 06-03-2007

Quote:

Originally Posted by MUMMZ

Yes I am getting spark to the rear plug, I found a loose connection in the spark plug wire so I put new wires on both. Also found another piece to the puzzle, at about 1/3 to 1/2 throttle (acceleration) the carb spits back into the air cleaner, after all I have done and all the things that I have checked I still find raw fuel in the air cleaner. I think it might be leaning towards a valve adjustment, and maybe some more tuning to the carb thanks for the link.

carb rebuild. float valves bad. fuel will either go into the airbox or the oil pan.

MUMMZ · 06-04-2007

thank you for the reply do you happen to know the setting for the float?

Trashman900C · 08-27-2008

how do you know if a spark plug is misfiring? or if you have a bad plug?

Thanks,
Robb

zedx11 · 08-28-2008

Robb, if the motor is not running smoothly it could be a spark problem or a fueling problem. it depends on when it is doing it.

Trashman900C · 08-28-2008

it just seems like its not running at full power during WOT, and the exhaust note seems to sound different (not as powerful)............maybe its just me.........

Trashman900C · 08-28-2008

my mileage was down on my last fill up also.......it was around 40-41mpg, since ive got the bike ive averaged 47-48mpg............

zedx11 · 08-28-2008

have you changed anything? new exhaust? air mod?

Trashman900C · 08-28-2008

i changed stuff but that was all last year.......the only thing different is i went back to 87 octane from 89..........

05-07-2007	#1 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	rear cylider misfires I recently noticed that my rear cylinder is misfiring, pretty badly, the front is solid as a rock though. Does anyone have some hints on where to start looking?

05-08-2007	#4 (permalink)
Scruffy Scooter Trash! BTK Expert Join Date: Sep 2005 Location: Buckley Wa USA Posts: 2,365	Which bike? Most metric twins have one coil per plug, sounds like you have an 800 or 900 if it is single plug. Go one heat range hotter on the rear plug. If you have an 800, that would be a CR6E instead of the stock CR7E. Not sure what the 900 takes plug-wise, haven't messed with one. If it still fouls out and stumbles/misfires, get a mechanic to check it out. -Scruffy __________________ Eagle Scout. Veteran. Patriot Guard Rider. 1950s style Savage barhopper 1950s style VN800B bagger

05-14-2007	#8 (permalink)
2WheelFun the "fun old" guy Extreme Forum Supporter Join Date: Nov 2004 Location: Albion, Washington "Pacific Northwest" Posts: 30,372	The settings sound right. Are you getting spark to the rear plug? __________________ *KING KAHUNA* *2007 V2K LT* ****PICS** 2007 Brute Force 650i **PICS** I love the smell of SeaFoam in the morning**

05-14-2007	#9 (permalink)
2WheelFun the "fun old" guy Extreme Forum Supporter Join Date: Nov 2004 Location: Albion, Washington "Pacific Northwest" Posts: 30,372	In case you haven't seen this post. http://www.kawasakimotorcycle.org/fo...djustment.html __________________ *KING KAHUNA* *2007 V2K LT* ****PICS** 2007 Brute Force 650i **PICS** I love the smell of SeaFoam in the morning**

08-27-2008	#14 (permalink)
Trashman900C The Incredible Vulc' BTK Expert Join Date: Jul 2007 Location: Long Island, NY Posts: 2,074	how do you know if a spark plug is misfiring? or if you have a bad plug? Thanks, Robb __________________ -Robb- Black 07' Vulcan 900 Custom VROC#: 24820 MeanCycleGallery Last edited by Trashman900C : 08-27-2008 at 10:29 PM.

05-07-2007	#2 (permalink)
OhioDrifter Uncle Bob's Love Child BTK Expert Join Date: Mar 2007 Location: Lorain, Ohio Posts: 278	Hi Mummz, I had a rear misfire on mine, I swapped the plugs (front to rear, rear to front) as a test. When moved to the front cylinder, offending plug still would not fire. Changed both plugs and no problem since.

05-08-2007	#3 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	Removed rear plug when I noticed the misfire, and it was very wet, changed out plug and noticed misfire again. Do they run off of separate coils?

05-08-2007	#5 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	Probably should have mentioned '02 Vulcan Classic 800. My concern is that it misfires badly at idle but drops off when cruising, unless at bottom end of gear. I don't think it has anything to do with mixture, but upon inspection of carb noticed had been rejetted, 162.5 for main and 48 for pilot, sounds right, but needle clip placement is on the second setting from top with two washers on top of clip ... wondering if that all adds up.

05-09-2007	#6 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	Does anyone know what the fuel float setting is supposed to be for the aforementioned bike, if so how do you go about resetting it?

05-14-2007	#7 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	Does anyone post answers to technical questions on this forum?

05-15-2007	#10 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	Yes I am getting spark to the rear plug, I found a loose connection in the spark plug wire so I put new wires on both. Also found another piece to the puzzle, at about 1/3 to 1/2 throttle (acceleration) the carb spits back into the air cleaner, after all I have done and all the things that I have checked I still find raw fuel in the air cleaner. I think it might be leaning towards a valve adjustment, and maybe some more tuning to the carb thanks for the link.

06-04-2007	#13 (permalink)
MUMMZ Banned Join Date: May 2007 Location: AZ Posts: 13	thank you for the reply do you happen to know the setting for the float?

08-28-2008	#15 (permalink)
zedx11 yellow doesn't corner wel Extreme Forum Supporter Join Date: Oct 2005 Location: KC, KS Posts: 22,146	Robb, if the motor is not running smoothly it could be a spark problem or a fueling problem. it depends on when it is doing it. __________________ Darrell Ignorance is a disease my friend. You should rid yourself of it.

08-28-2008	#16 (permalink)
Trashman900C The Incredible Vulc' BTK Expert Join Date: Jul 2007 Location: Long Island, NY Posts: 2,074	it just seems like its not running at full power during WOT, and the exhaust note seems to sound different (not as powerful)............maybe its just me......... __________________ -Robb- Black 07' Vulcan 900 Custom VROC#: 24820 MeanCycleGallery

08-28-2008	#17 (permalink)
Trashman900C The Incredible Vulc' BTK Expert Join Date: Jul 2007 Location: Long Island, NY Posts: 2,074	my mileage was down on my last fill up also.......it was around 40-41mpg, since ive got the bike ive averaged 47-48mpg............ __________________ -Robb- Black 07' Vulcan 900 Custom VROC#: 24820 MeanCycleGallery

08-28-2008	#18 (permalink)
zedx11 yellow doesn't corner wel Extreme Forum Supporter Join Date: Oct 2005 Location: KC, KS Posts: 22,146	have you changed anything? new exhaust? air mod? __________________ Darrell Ignorance is a disease my friend. You should rid yourself of it.

08-28-2008	#19 (permalink)
Trashman900C The Incredible Vulc' BTK Expert Join Date: Jul 2007 Location: Long Island, NY Posts: 2,074	i changed stuff but that was all last year.......the only thing different is i went back to 87 octane from 89.......... __________________ -Robb- Black 07' Vulcan 900 Custom VROC#: 24820 MeanCycleGallery

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Heavy Cruisers & Brakes	LordGT	Kawasaki Cruisers	57	08-02-2008 02:14 AM
VN2000 rear noise gone--for now	snw1953	Kawasaki Cruisers	2	04-02-2007 05:52 PM
Shifting/braking	StangGT	Kawasaki Streetbikes/Sportbikes	33	10-01-2006 11:20 PM
750 Vulcan rear end tear down & Motorcycle Lift	2WheelFun	Kawasaki Cruisers	4	09-26-2005 10:04 AM
WTB: rear seat and rear pegs for '03 zx6r	import monkey	Accessory Swap Meet	0	08-12-2005 02:15 PM