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Discussion Starter #1 (Edited)
My new (Old) bike is experiencing a misfire problem.

1996 with only 2400 miles.

At first it stalled on the way home, after a couple of days of running fine, waited 10 mins and it restarted.

I added Berryman's Chemtool to the tank and ran it the next day.

I then filled up with gas and it begain missing on the front cylinder. Both plugs were wet. I then changed the plugs to no avail. It appeared the front cylinder wa now flooding. I took the plugs out, (they all were firing) and left it for 10 mins, then cranked it over to see a lot of fuel expelled from the front plug holes.

I then decided to clean the carbs, (stuck float ya know!). No more flooding but still missing from the front. the backpressure on the right (front) exhaust is not as strong as the left. Still all plugs are firing when tested against the frame, although not a massive blue flame as in my car, but all four plugs apear to fire approximatly the same strength.

Did resistance check on the coils, OK.

This thing is driving me crazy.... A little help Please.

Oh, yea.... I changed out the gas.

Thanks ahead of time guys for the assistance.

Forgot to say New M/F Battery (Yuasa: YTX14AHL-BS)

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09/16/06 Update - I am listing all things done to the bike since this problem started......

... Rinsed out tank with gas.

... Dissasembled and cleaned Petcock and filters.

... Changed oil and filter

... Drain and refil Radiator w/ Dexcool (no water) (I know what they say....)

... Drain and refil rear gearbox

... Relube final drive w/ Honda moly (has been done before, hoorah!)

... Check compression, (Front 160, Rear 155)

... Check vacuum (wildly swings at idle, then smothes out with throttle)

... Sync carbs (synced at 4000, way off at idle)

... Installed Capacitors on regulator wiring

... Wired coils direct to batt. (thru relay)

... Added voltmeter (led) thru relay

... New Plugs (Iridium), Wires and Caps (NGK)

... Just for the record, I think I found the problem, I took the carbs off for the FOURTH time, and found both floats the be stuck closed. This apparently happened when I shot a ton of Gummout in reverse thru the drain hole. At first only the front cylinder was effected, and the more I shot it up, the worse it got. Now remember I have cleaned the carbs TWICE before and once was a soak in carb dunk, so what ever is in the fuel (or was) or whatever is in the Gummout, is not meant for these carbs.

I will copy this fix to the reply, hopefully with all in one post, the answers will be easier to find.

Anyway...the bike is up and running again....

I will start another post about the vacuum problems I am having in another forum
 

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I looked up Chemtool, and it is not SeaFoam-like. Other than it is a cleaner. Get some Seafoam, and run 3 oz of that through a tank o' gas instead of chemtool. You might want to get some cheap clear fuel filters to run inline with the carbs for a little while. If the bike only had 2000 miles on it (per previous thread), then it suredly has rust in the tank, or some other such gunk.

It might also be beneficial to you to try Fergy's coil mod. That would give you better spark. http://pages.tstar.net/~fergy/writeups/coil_relay_mod.html

You did change the oil, right? Liquid gas in the cylinder will filter past the rings into the crankcase, and dilute your oil.

Seafoam:
 

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Discussion Starter #3
I am sure you are correct, but having used Berryman's for many, many,many years, and trust it's ability to clean fuel systems, I opted to err on the side of caution as I know what it can do and I am not yet familiar with the results of Seafoam so that is my reasoning.

Yes I did change the oil and the gas.

Of course I cannot run a tank of Seafoam if I cannot get the bike to run right.

I appreciate the response as I need all the help I can get.
 

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i'm might not be the best MC tech around here, but it sounds still like carb related to me.

if there is alot of rust in the tank like cegodsey mentioned, your clean carbs will get clogged up again pretty soon.
 

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If you do a search on Seafoam in this forum, I think you'll understand how we feel about it. It's primarily 3 ingredients - pale oil, isopropyl, and naptha. At least those are all the ingredients required to be listed on the MSDS. To us, it's magic. I haven't used it in my bike yet, but I have used it in my Honda mower, and I must admit, it's majick!

If I were you, I'd do a compression test on that front cylinder, just in case. Check the igniter (CDI, ingition module) resistance per the manual. You also might try switching the coils. It could also be related to the coil pickups behind the left engine cover.
 

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Discussion Starter #6
cegodsey - I thought about swaping the coils, but it makes no sense that all plugs are firing about the same intensity.

I will use the Seafoam the first chance I get to ride the bike I just bought and have no miles on......
 

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sounds like a clogged jet it just dripping gas into the intake maybe. I am still learning carbs, but i know what you are describing is very similar to a clogged injector. try nursing it off of some sea foam gas mix. if that doesnt work, sounds like you may have a carb pull on your hands.
 

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dta116 said:
My new (Old) bike is experiencing a misfire problem.

1996 with only 2400 miles.

At first it stalled on the way home, after a couple of days of running fine, waited 10 mins and it restarted.

I added Berryman's Chemtool to the tank and ran it the next day.

I then filled up with gas and it begain missing on the front cylinder. Both plugs were wet. I then changed the plugs to no avail. It appeared the front cylinder wa now flooding. I took the plugs out, (they all were firing) and left it for 10 mins, then cranked it over to see a lot of fuel expelled from the front plug holes.

I then decided to clean the carbs, (stuck float ya know!). No more flooding but still missing from the front. the backpressure on the right (front) exhaust is not as strong as the left. Still all plugs are firing when tested against the frame, although not a massive blue flame as in my car, but all four plugs apear to fire approximatly the same strength.

Did resistance check on the coils, OK.

This thing is driving me crazy.... A little help Please.

Oh, yea.... I changed out the gas.

Thanks ahead of time guys for the assistance.

Forgot to say New M/F Battery (Yuasa: YTX14AHL-BS)
SEAFOAM is all you will need... it is the best...
 

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Seafoam is a miracle drug, Lena loves it. Put it in my Subaru's oil to see
if it would stop my noisy sticky valves... and it helped quite a bit and
the valve sounds are getting quieter every time I start it up.

Good deal on it here at an ACE Hardware store ... 4.99 for the round can on the right that
CEgosey posted a pic of.
 

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Discussion Starter #10
Well, another weekend shot to hell! I rebuilt the carbs and did a hundred other mods while it was down waiting for a lost o-ring........

Cranked her back up sunday, sounded like crap....waited a while and tried again and it sounded better, waited some more and it sounded about right so I adjusted the idle screws, throtle linkage, and Idle then rode about 10 miles. It ran like it is supposed to, (maybe better) so I decided to take it to work this morning.

Well, about 5 miles down the loop doing 60, it starts missing, so I make it to work.

After work I take the city streets back home without problems, but as soon as I get back on the loop to get my exit, It starts cutting out again at around 60mph. I get home and pull the tank and petcock to look-see and everything is crystal clean. what in the world could this gremlin be?

It sounds like a fuel filter but we don't have one (just the tank filter), but I blew that out and checked it thoroughly. It only seems to happen at 60 or better.

I cannot tell if one cylinder or the other is missing.

Anybody interested in a VN750?
 

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dta116 said:
Well, another weekend shot to hell! I rebuilt the carbs and did a hundred other mods while it was down waiting for a lost o-ring........

Cranked her back up sunday, sounded like crap....waited a while and tried again and it sounded better, waited some more and it sounded about right so I adjusted the idle screws, throtle linkage, and Idle then rode about 10 miles. It ran like it is supposed to, (maybe better) so I decided to take it to work this morning.

Well, about 5 miles down the loop doing 60, it starts missing, so I make it to work.

After work I take the city streets back home without problems, but as soon as I get back on the loop to get my exit, It starts cutting out again at around 60mph. I get home and pull the tank and petcock to look-see and everything is crystal clean. what in the world could this gremlin be?

It sounds like a fuel filter but we don't have one (just the tank filter), but I blew that out and checked it thoroughly. It only seems to happen at 60 or better.

I cannot tell if one cylinder or the other is missing.

Anybody interested in a VN750?
Shot in the dark, so to speak. Check the spark plug cables to see if they are shorting out on the throttle cables. The right front plug normally comes close to, but shouldn't be touching the spark plug cable. Get the bike somewhere as dark as possible and start it up. Look for blue sparks from the plug wires and boots jumping to cables. The insulation on old cables starts to break down. It's not too hard to route the throttle cables incorrectly so that they touch the spark plug boot too.
 

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Discussion Starter #12
I replaced the spark plug wires and caps before the last write-up .....

The right front plug cap must touch the throttle cables, there is no where else to route the cables.

Thanks for the assistance...
 

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dta116 said:
I replaced the spark plug wires and caps before the last write-up .....

The right front plug cap must touch the throttle cables, there is no where else to route the cables.

Thanks for the assistance...
Check something for me. Are the throttle cables routed foreward of, or aft of the air duct on the right side? If they're routed aft of the duct, they can be adjusted so they don't touch the spark plug. (Push the slack up in front of the handlebars) Mine were routed foreward of the duct by the mechanic that did the engine pull. That takes all of the slack out of the cable and they have to rest on the boot. I didn't know the difference until I met up with about 6 other Vulcan owners and noticed that all of their's were aft of the duct. After a bit of fussing with the air duct and case, I was able to get the air filter case off and move the cables. Probably won't fix your problem if you have new wires, but it can keep the cable off of the spark plug boot.

Did you check the vent hose that goes into a slot in the back of the, I think, right air cleaner case? If that bottoms out in the slot it can cause rough running at high rpm.
 

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Dang it, I forgot about that vent hose. If that was the problem, then I must bow down to you, Ironman. :notworthy
 

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Discussion Starter #15
All of these solutions have been done, still missing....

I will edit my first post when I get a chance and list all the solution accomplished...

I really appreciate the assistance.

Update....I sprayed Gumout into the carbs through the drain hole and now no fuel to the front carb.....

Man, I need a new attitude !!!!!

Thanks again.
 

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Looks like regular use of Seafoam could have prevented this problem but A direct shot of carb cleaner would be a good place to start for these types of problems.. Glad you're back on the road.
Oops, did you mean no fuel at all or no excess fuel?
 

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dta116 said:
All of these solutions have been done, still missing....

I will edit my first post when I get a chance and list all the solution accomplished...

I really appreciate the assistance.

Update....I sprayed Gumout into the carbs through the drain hole and now no fuel to the front carb.....

Man, I need a new attitude !!!!!

Thanks again.
Take the vent hose out of the right air box and point it straight forward. I found that playing with the vent hose while cruising along will affect how the bike performs. The bike doesn't run right when that vent tube is in the air box, faces outward, or faces backwards.
 

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Discussion Starter #19 (Edited)
... Just for the record, I think I found the problem, I took the carbs off for the FOURTH time, and found both floats to be stuck closed. This apparently happened when I shot a ton of Gummout in reverse thru the drain hole. At first only the front cylinder was effected, and the more I shot it up, the worse it got. Now remember I have cleaned the carbs TWICE before and once was a soak in carb dunk, so what ever is in the fuel (or was) or whatever is in the Gummout, is not meant for these carbs.

I will copy this fix to the reply, hopefully with all in one post, the answers will be easier to find.

Anyway...the bike is up and running again....

I still feel I have some performance issues, but I will address them in another forum.

Thanks to all who assisted with these solutions. It is certainly appreciated.

I will probably be doing mods on this bike until I run out of things to do or buy a 900, so hopefully my experiences will benifit others on this forum.

I will take pics of my mods and post them here. ( I am not exactly sure which forum is designed for that). Any Help?

Thanks again.

Dave
 

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Get the SEA FOAM. It will take care of those carb problems. Really.

You can post pics here. The absolutely easiest way is to go to the gallery and upload them. You might want to optimize them before doing so, as there is a size limit per pic. I'm gonna post some instructions on here with visuals soon.
 
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