Author Topic: Missfire during acceleration at all RPM’s  (Read 1012 times)

0 Members and 1 Guest are viewing this topic.

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Missfire during acceleration at all RPM’s
« on: June 25, 2018, 12:39:02 pm »
Hey everyone hows it going, i currently picked up a 2002 C10 with 45 thousand miles. The bike is in overall great condition the old man who sold it to me was just getting to that age that he couldn't ride such  a big bike. So with That being said i purchased the bike and immediately reaplaced the spark plugs and cleaned the carbs. After installing the pieces back together, i noticed that the bike immediately began to missfire. At idle the bike runs fine, bur at low RPM’s  on acceleration the bike kinda sputters and you can definitely hear the raw fuel being dumped from the back of the bike. When i cleaned the carbs i left the Needles  and seats alone. But i did let the jets soak in carb clean, sprayed them with carb clean and then used compressed air to blow anything else out. What could be the cause to such a problem ? I bought the clymers manual and the troubleshooting said either bad coils or a incorrectly adjusted carburetor. I'm not to sure if there was a common problem on the ignition system on these bikes or i did something wrong. I used copper NGK plugs and replaced all four of them. If anyone could help me that’d be great because I’m kinda stuck as of right now

Offline RWulf

  • Crotch Rocket
  • ****
  • Posts: 1638
  • AREA: North Central Area
  • COG#: 7122
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #1 on: June 25, 2018, 12:56:43 pm »
You can hear raw fuel dumping from the back of the bike, that's not right.
Find out what is causing this and fix it. Do you see any fuel dripping on the
ground? Only thing I can think of would be a split fuel line. That could
cause all your problems.
Good luck and watch out for fires.

Offline Pbfoot

  • Crotch Rocket
  • ****
  • Posts: 1249
  • AREA: South Central Area
  • COG#: 10807
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #2 on: June 25, 2018, 01:18:21 pm »
If you didn't pull the pilot jets you didn't go far enough. Classic pilot jet clog. Misfires at idle, sputters up to 3500 or so and then clears out. Pull the carbs again. Remove the caps from the pilot screws and remove them. Spray carb cleaner through the pilot holes. Remove the diaphrams first as carb cleaner will attack the rubber.  I would replace the petcock and have overflow tubes installed in the bowl to avoid hydrolocking the engine.
If you don't have time to do it right, when do you have time to do it over.                                                                17" wheels, Nissin 4 piston calipers.1kg Sonic Springs.Cartridge Fork Emulators. KB Brace. Galfer brake lines  Free power mod.

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #3 on: June 25, 2018, 01:30:53 pm »
I pulled the main jets only, as i couldn’t find a skinny enough screw driver to fix down that hole. And pbfoot the bike runs fine at idle, but at speed around 2000 to 3500 RPM’s the missfire is very dominant. And as the revolutions increase the missfire seems to go away. That’s why i was looking into maybe a coil pack or just a bad plug. But I’m a bit confused because the plugs were replaced less than 30 miles ago. I’ll try to remove the carbs again and clean the pilot jet I’ll have to shave down a screwdriver and see what it looks like. So in both of your opinions do you think this is a carburetor related issue or more towards the ignition system. I’m trying to pinpoint an exact spot where to fix the problem. Rwolf i didn’t mean to say it like that what i meant was that you can hear the raw fuel being dumped out of the exhaust in little sputters and pops as if the engine can ignite the fuel. Sorry for the confusing wording. Also another reason why I’m confused is that the bike ran portly at higher speeds before i cleaned the main jet and ran perfect idle to 3500.

Offline Pbfoot

  • Crotch Rocket
  • ****
  • Posts: 1249
  • AREA: South Central Area
  • COG#: 10807
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #4 on: June 25, 2018, 01:50:49 pm »
Yes. Pull the pilot jets. I don't think it is an ignition problem. The pilots operate at idle thru 3500 where the main jets take over.
If you don't have time to do it right, when do you have time to do it over.                                                                17" wheels, Nissin 4 piston calipers.1kg Sonic Springs.Cartridge Fork Emulators. KB Brace. Galfer brake lines  Free power mod.

Offline connie_rider

  • "OtP" {retired/assistant} Slave Labor
  • I Need a Life
  • ******
  • Posts: 8005
  • Help us make "OtP" possible! "AGAIN"
  • AREA: South Central Area
  • COG#: 4154
  • Membership Level: Asst. Area Director
Re: Missfire during acceleration at all RPM’s
« Reply #5 on: June 25, 2018, 03:27:03 pm »
If you have raw gas coming out, probably carbs,
BUT: Before you pull the carbs, check your spark plug wires and boots.
          Be sure they are fully pushed on the plugs, and the wires are well into the coils/plugs...
          Might save you pulling the carbs.
              {Don't ask me how I know this}..  :-[

Ride safe, Ted
14 Connie (Traveler II) / 03 Connie (Buddy)
Gone but not forgotten; 87 and 00 Connies..

If your not already a COGger, "consider becoming one".
Help us make "OtP" possible again, DO IT NOW!!

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #6 on: June 25, 2018, 03:44:38 pm »
That’s the plan lol I’m gonna check the plugs and the leads for proper installation plus I’m going to check the resistance values for the primary and secondary windings. Before removing the plugs, but from what pbfoot has said previously that sounds to be my issue. But I’m gonna take it one step at a time and easiest to hardest. i appreciate all the input and will be doing the ignition system today and will keep updated on what the problem was. Thank you

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #7 on: June 25, 2018, 03:50:39 pm »
Also Connie_rider what i meant by dumping raw fuel was it’s like the spark plugs didn’t have enough omph to ignite the fuel and as the events of the engine change the raw fuel is just dumped out the exhaust and smells extremely rich

Offline WillyP

  • I Need a Life
  • ******
  • Posts: 6059
  • Live Free Or Die
    • Suncook Carpentry
  • AREA: Northeast Area
  • COG#: 8799
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #8 on: June 25, 2018, 04:02:51 pm »
Why did you replace the plugs and clean the carbs? Was the bike misfiring before you did this work? When you say you soaked the jets did you remove them first, or did you mean to say you soaked the whole carb? Did you remove the diaphragms before soaking or spraying carb cleaner into the carbs?
When you say you left the needles and seats alone do you mean the needle valve on the slide? And what about the float valves, did you clean the seats and set float levels, and how did you do it? Did you clean the tank and petcock? Are you using fresh gas? Have the carbs had Steve's jet kit installed yet?
Smart people look like crazy people to stupid people.
pics

Offline Pbfoot

  • Crotch Rocket
  • ****
  • Posts: 1249
  • AREA: South Central Area
  • COG#: 10807
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #9 on: June 25, 2018, 04:25:59 pm »
Don't throw any parts at it until you sort out the carbs. If it were truly misfiring at all rpms, I would say ignition. That being said, the fact that it does clear at high rpms, tells me it is the pilot jets. I've been down this road several times due to failing petcock screens. Why I run a filter.
If you don't have time to do it right, when do you have time to do it over.                                                                17" wheels, Nissin 4 piston calipers.1kg Sonic Springs.Cartridge Fork Emulators. KB Brace. Galfer brake lines  Free power mod.

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #10 on: June 25, 2018, 06:09:48 pm »
WillyP i serviced the carbs due to them running rough at higher speeds. I also changed the plugs while i was in there along with a new air filter. The bike didn't misfire before this service so i'm not to sure as to what i did or what happened. I removed the jets and diaphragm before i cleaned the entire housing and soaked the jets in the solvent along with a quick blast of carb clean and compressed air to clean them finally. I didnt touch the floats and needles but i quickly sprayed the floats and the top of the needles. i didn't clean the tank because it uses a in line filter and the gas tank didnt seem nasty the tank appears to be clean. or change float levels. Its had like five brand new tanks of gas so that shouldn't be an issue.
Pbfoot the only thing i plan on doing for sure is getting a APE mechanical cam tensioner unless you guys have a better idea on what to get and preferably cheaper. I plan on going down the checklist and testing the coil packs and wires for resistance and unless its absolutely necessary buy a rebuild kit for the carbs. My first time removing the carbs was the worst time of my life to the point where i was gonna roll my bike into the street and have a free sign in the middle of the road lol. So if i can avoid that i will at all cost. I could use a laser thermometer and cruise around town under three thousand to pinpoint the exact cylinder misfiring. The other reason why i cant tell exactly is because the tensioner makes so much noise it sounds like engine knocking as the RPM increases the knock gets more prevalent. so i'm gonna do the steps and see what i can do 

Offline Pbfoot

  • Crotch Rocket
  • ****
  • Posts: 1249
  • AREA: South Central Area
  • COG#: 10807
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #11 on: June 25, 2018, 06:48:01 pm »
It is a tough job the first time. Lol. I feel your pain. New airbox boots really eases r&r. You could clean the pilots without disassembly since they are outside of the float bowl. Not recommended as you can blow the crud right back in the bowl. Instead of using an ohm meter, just hook up each plug wire to a timing light. You will see any misfire as an irregular light. Very easy. If it misses but the light is steady it is carburetion. As far as the ape goes, be careful, too tight and you wipe out the cam bearing surface. Proper adjustment would be if it ticks a little at cold startup and then goes away. In my case I followed Connie Riders advice and took the adjuster bolt out and gave a light tap with a hammer and punch to move the factory adjuster in a notch.
« Last Edit: June 25, 2018, 06:51:40 pm by Pbfoot »
If you don't have time to do it right, when do you have time to do it over.                                                                17" wheels, Nissin 4 piston calipers.1kg Sonic Springs.Cartridge Fork Emulators. KB Brace. Galfer brake lines  Free power mod.

Online MAN OF BLUES

  • I Need a Life
  • ******
  • Posts: 7562
  • AREA: North Central Area
  • COG#: 5977
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #12 on: June 25, 2018, 07:28:02 pm »
stop and step back...
don't start adding new parts that are not needed until you need them, like a manual chain tensioner... I hear all these crazy things all the time, people wanting to toss a barrage of parts onto something that they have not defined. A new chain adjuster, when you have not adjusted and manually inspected the valve clearances yet, is a waste of time and money.. adjust your valves.

it stems from something directly related to the servicing you did, if it runs worse now, than it did prior.
I'm not going to go into "what may be wrong with your carbs", as I don't have them in hand, and have seen every permutation of missed steps in correct cleaning and assembly...
so I'll move on to why there is unburnt fuel in the exhaust...

my guess, is when you pulled the spark plugs, you compromised the plug ends, it doesn't take much effort, and they became displaced from the wire core. The plug ends actually have a 1/2" long threaded "pin" that runs up inside of the wire, and must be 'screwed' onto the wire end to cause the pin to thread up inside the wire. These often become corroded, along with the actual wire inside the insulation, and if tugged on, will cause a hard to find intermittant miss, exactly as you describe...even using an inductive timing light may miss the fact that while fireing, it ain't getting the "HOT" spark it really needs...  I know this from experience, as I assumed ONCE that because it fired the timing light, the connections were fine... I was wrong...

so, before spending any money, remove the tank, and pull the wires from each plug, then grab the end and 'unscrew' them while pulling on them.
Inspect the actual 'core' of the wire,(the OEM wires are a solid tinned copper stranded wire) it's likely green and corroded... snip off about 1/2" to 3/4" from the end, and check if the wire is shiney there on the end, then while holding the plug end firmly, press it onto the wire fully, and begin threading it on/in, it should go about 1/2" before it's fully home...
then check the bikes operation. Ohming out the wires prior, doesn't always show the connection was bad, as it breaks down at higher rpm's due to the compromised continuity.

it doesn't cost anything.
« Last Edit: June 25, 2018, 07:35:25 pm by MAN OF BLUES »

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #13 on: June 25, 2018, 08:42:24 pm »
I did take them off, while using a dvom i found that the right coil pack has a resistance value of 3.1 while the factory spec is the top scale 2.8 whoch could mean a colder spark and potentially cause a misfire i did in fact pull cylinder 3 plug out and rippes the wire out and it was found to be corroded and green like you said. Also the wires on the coil pack on the primary side arw reading 30 millivolts and the other side is reading .3 volts. Are there two wires that connect to the coil pack supposed to be 12 volts ?

Online MAN OF BLUES

  • I Need a Life
  • ******
  • Posts: 7562
  • AREA: North Central Area
  • COG#: 5977
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #14 on: June 25, 2018, 09:40:41 pm »
I did take them off, while using a dvom i found that the right coil pack has a resistance value of 3.1 while the factory spec is the top scale 2.8 whoch could mean a colder spark and potentially cause a misfire i did in fact pull cylinder 3 plug out and rippes the wire out and it was found to be corroded and green like you said. Also the wires on the coil pack on the primary side arw reading 30 millivolts and the other side is reading .3 volts. Are there two wires that connect to the coil pack supposed to be 12 volts ?

the red wire is +12v, the black(cyl 1 & 4) or green lead (cyl 2 & 3) (depending on which side) are the neg - leads. as far as the individual coils function, the positions on the coil itself do not matter, but I can't attest to that... it is stated in the FSM tho. Just for the sake of continuity, attach the red wire to the position marked + on both... ok?

as far as coil values, you lost me with the milivolt thing... its all an OHM thing, checking resistance, without the caps...
see the attached sheet...

« Last Edit: June 25, 2018, 10:04:47 pm by MAN OF BLUES »

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline connie_rider

  • "OtP" {retired/assistant} Slave Labor
  • I Need a Life
  • ******
  • Posts: 8005
  • Help us make "OtP" possible! "AGAIN"
  • AREA: South Central Area
  • COG#: 4154
  • Membership Level: Asst. Area Director
Re: Missfire during acceleration at all RPM’s
« Reply #15 on: June 25, 2018, 10:43:03 pm »
I thought his miss was at all RPM's.
    Missed where he said it ran ok at higher RPM's?

Reading this about possible weak fire, Steve's free power mod comes to mind...
Anybody have the link to his video handy?

When/if you pull the carbs be sure to check the float levels...

Ride safe, Ted
14 Connie (Traveler II) / 03 Connie (Buddy)
Gone but not forgotten; 87 and 00 Connies..

If your not already a COGger, "consider becoming one".
Help us make "OtP" possible again, DO IT NOW!!

Offline Bud

  • Street Cruiser
  • ****
  • Posts: 582
  • AREA: North Central Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #16 on: June 25, 2018, 10:48:52 pm »

Online MAN OF BLUES

  • I Need a Life
  • ******
  • Posts: 7562
  • AREA: North Central Area
  • COG#: 5977
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #17 on: June 25, 2018, 11:06:25 pm »
I thought his miss was at all RPM's.
    Missed where he said it ran ok at higher RPM's?

Reading this about possible weak fire, Steve's free power mod comes to mind...
Anybody have the link to his video handy?

When/if you pull the carbs be sure to check the float levels...

Ride safe, Ted

the free power mod helps bikes with normal performance, but it doesn't fix bad plug wires...
i did in fact pull cylinder 3 plug out and rippes the wire out and it was found to be corroded and green like you said.

when he gets all 4 finished, and replaced, I would expect some improvement. :rotflmao: :rotflmao: :motonoises:

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #18 on: June 26, 2018, 06:07:43 pm »
So i tested the wires that connect to the primary side of the coil pack and found it to be nowhere near 12 volts or anything constant to that. Like man of blues said the ignition leads were found to be pretty corroded and needed to be cut and spun back into the fitting so i did that. When i tested both coil packs for resistance i found out that the coil pack for cyl 1 and 4 was reading 2.8 ohms which according to the clymers manual is at the top of the resistance allowed. While the coil pack for cyl 2 and 3 was found to have a resistance of 3.1 which is above the threshold of 2.8. One thing i did was to put the coil packs in the freezer and hear me out on this, as we all know the hotter a wire gets the more resistance it has so i left my coil packs into the freezer for a hour, and after taking them out i tested them to find one coil pack at 2.1 ohms and the other to be at 2.4 ohms. I reinstalled them after fixing the ignition leads to remove the corrosion and made good contact with the screw and the fitting for the coil packs themselves. After putting everything back together i ran the bike and for about a hour the bike ran a lot better no missfire and smooth acceleration almost like nothing was wrong. But as it got hotter and reved higher the bike began to misfire again. So in all honesty I’m thinking that it’s is a combination of something wrong with the wires to the primary side of the coil pack. And broken coil packs and ignition leads. Another note was the fact that the spark plugs in all four cylinders were found to be whiter than a ghost from either being extremely lean or just cannot combust the fuel.

Offline connie_rider

  • "OtP" {retired/assistant} Slave Labor
  • I Need a Life
  • ******
  • Posts: 8005
  • Help us make "OtP" possible! "AGAIN"
  • AREA: South Central Area
  • COG#: 4154
  • Membership Level: Asst. Area Director
Re: Missfire during acceleration at all RPM’s
« Reply #19 on: June 26, 2018, 07:55:24 pm »
Others will know more than I.

Some of your problem might be corrosion where the spark plug cap makes contact with the plug.
  An EZ way to improve that is to clean the surface by repeatedly pushing a plug and out of the connection.
Also check your grounds near/at the battery and coils. {and maybe do Steve's free power Mod per the video}.
All of these things should reduce some of the corrosion/resistance, and give you just enough voltage to see if your on the right track.

While the bike was running better, did you notice any rich fuel smell or leakage?
If you still have raw fuel problems,,, it's back to the carbs.

Ride safe, Ted
14 Connie (Traveler II) / 03 Connie (Buddy)
Gone but not forgotten; 87 and 00 Connies..

If your not already a COGger, "consider becoming one".
Help us make "OtP" possible again, DO IT NOW!!

Online MAN OF BLUES

  • I Need a Life
  • ******
  • Posts: 7562
  • AREA: North Central Area
  • COG#: 5977
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #20 on: June 26, 2018, 09:09:39 pm »
So i tested the wires that connect to the primary side of the coil pack and found it to be nowhere near 12 volts or anything constant to that. ....

think about this.
do you think there is always 12v running to the coil?
why?
if that was how they work... there would be a constant 'spark' going on....

that outcome is directly related to that testing machine, noted in the file I attached, where voltage is supplied to a coil,which is emulated by that machine to recreate the signal from a trigger coil and igniter box combo  and the 3 point spark arc tester shows the spark strength, which would be like 7mm (1/4"+)

did you inspect the primary coil tabs using an OHM meter, per the instruction sheet I attached? yes you did, good. Now, that figure you found, all though higher on one, is still within the realms of an operational coil...it didn't register low, which would indicate an internal short, nor did it indicate real high, or even Infinite, would would indicate a broken internal winding.
 
only time either ignition coil see full volts, on the primary side, is when the timing rotor triggers the pickup sensing coil....triggering the igniter box to send juice to the coil.

what was the outcome of the OHM testing between the 2 spark plug wires (with the plug caps removed) ? did that fall into the noted range on the spec's?
you may have a coil going bad, but it's a coin toss as the values on the primary side were not astoundingly off... the OHM testing on the primary does not always show "layer shorts, or internal insulation break down at high voltages", usually present on the secondary side.

also, to add, if a plug isn't firing, it surely will not be 'clean' or 'white' as you noted, it will be dirty, wet, and fouled, as raw fuel isn't being burned.

again, this all surfaced after the carbs and plugs were done...
I personally find that doing carb work, without doing a valve clearance inspection and adjust, is not gonna do much other than labor, as you can't synch carbs without having the valves adjusted... well, you can, but it's a bandaid.
granted, coils do go bad, but there may be other things adding into this, go ahead and check the resistance values on the timing pickup coils, and also check the gaps. And even do the 'free power' mod, to insure the igniter is getting all it's juice... but, it was running before service was done...
« Last Edit: June 26, 2018, 09:42:57 pm by MAN OF BLUES »

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline Chow

  • Tricycle
  • Posts: 17
  • AREA: Northeast Area
  • COG#: Forum
  • Membership Level: Forum Subscriber
Re: Missfire during acceleration at all RPM’s
« Reply #21 on: June 27, 2018, 11:24:55 am »
I tested the leads just for continuity. And all four made the light beep so i was happy with that. It just seems weird to me how i touch the ignition system it works for a hour and then goes back to the way it was. The resistance is high for both coils and one is over the limit. The clymers manual boated that if these coil packs were higher than the specified range to just replace them. I’m gonna do one thing at a time and slowly go down the list. I’m almost positive it was the ignition system giving the trouble so I’ll try to find some coil packs through a salvage yard or something and buy new ignition leads. I’ll keep everyone updated as to what the problem was thanks.

Offline connie_rider

  • "OtP" {retired/assistant} Slave Labor
  • I Need a Life
  • ******
  • Posts: 8005
  • Help us make "OtP" possible! "AGAIN"
  • AREA: South Central Area
  • COG#: 4154
  • Membership Level: Asst. Area Director
Re: Missfire during acceleration at all RPM’s
« Reply #22 on: June 27, 2018, 12:58:29 pm »
Chow, Before you buy used coils ( that may have bad wires too), trim the ends of your wires and clean the contacts at the plug, and/or change out your wires.

I fought a similar problem. My bike would sometimes run good, sometimes bad. 
It gave indications of fuel starvation or carb problems. All this happened after I did some maintenance that involved removing and reinstalling the coils..
I went thru the carbs, then had Steve do them, did valve adjust, new petcock, checked timing, checked my wiring, adjusted 2 min jett kit (foam) repeatedly, etc etc.

Drove me and everyone else crazy.
Eventually Steve figured it out and had us replace the wires and caps (available from Murph)
Problem solved.

I am not saying this will solve the problem. Your bike may have other problems.
MOB seems to think you have valve adjust problems?
It is just an inexpensive way to rule the wires/caps out.

Ride safe, Ted
14 Connie (Traveler II) / 03 Connie (Buddy)
Gone but not forgotten; 87 and 00 Connies..

If your not already a COGger, "consider becoming one".
Help us make "OtP" possible again, DO IT NOW!!

Offline BrianD

  • Bicycle
  • *
  • Posts: 128
  • AREA: Northeast Area
  • COG#: 11685
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #23 on: June 27, 2018, 01:14:49 pm »
I chased a similar problem to this on my '02 a year or so ago.  This is what turned out to be the problem - the little screw end inside the plug cap had broken off.  If you haven't replaced your wires and plug caps yet, do it now before wasting any more time and/or money.

Brian Dutton
Coventry, CT
'02 Concours

Offline Brooke_Benfield_OR

  • Moped
  • **
  • Posts: 226
  • AREA: Northwest Area
  • COG#: 2185
  • Membership Level: Active
Re: Missfire during acceleration at all RPM’s
« Reply #24 on: June 27, 2018, 04:19:53 pm »
There's a 5Kohm resistor inside the plug caps which can be accessed from the plug side of the cap with a regular screwdriver. You could have some corrosion in there not helping your situation. It's also possible the connection from the wire side of the cap to where the resistor is could be compromised so the earlier suggestion of new wires/caps is worthwhile.

Several year ago I bought generic NGK caps from a motorcycle dealer for like $3.50 each and got regular automobile bulk spark wire and made up my own new sparkplug wires. Talk about CHE...FRUGAL.
Brooke Benfield  2013 FJR1300  COG #2185