Bonneville America Forums Forums Technical Forums General Tech first problem: cuts out, backfires, then runs

have 22,500 miles and had my first problem.

the other day, after about 2 miles from work, my bike started to cut out (30 mph or so)about 15 seconds or so, then it backfired, then ran fine. it sounded and felt like it backfired out of the right carb.

today (bike sat about a week)after about 40 miles, mostly interstate (65-70 mph or so), the bike started to run poorly, like it was on 1 cylinder. this was about for a minute or 2, then it jolted, then ran fine.

it happened again after about 5 miles... i hit a bump, it backfired, then it ran fine the rest of the way home, about 30 miles.

could this be a coil? vent tube?
any help/ advice welcomed.

cat

I've been having a similar problem, with no solution. My bike is also just past 23k. Happened three times on the 1st day of a trip this week, but none on the 2nd and none since.
I ordered a new set of plug wires from Brent. Ruled out the kickstand switch. Ran like a champ today on short errands.

My related thread - Al's Intermittent problem

did you check the rubber couplers that are mounted to the carbs. Might be dry rotted and cracked

i checked the battery connections and the positive terminal was a little corroded. while cleaning it up, found a cut in the insulation exposing the copper wire where it had either worn or was pinched. i taped it good and put it back together.

i also took out the tank bolt and made sure the vent tube was clear, then bolted it back up.

took it for a 15 miles ride and it ran good.

i guess it'll be wait and see.

i'll check the rubber intakes but i did nose around there a bit and didn't notice anything.

one of the rubber corks (airbox) was a bit loose and i pushed it back in tightly.

i'm still wondering about the coils though.

cat

My carb rubbers are in good shape. I did discover my carb vacuum caps were in bad shape and replaced them (still had problems).
I'll see what the plug wires do before dropping $150 on new coils.

I had the exact same problem at the beginning of the riding season. I went over all electrical connections and changed coils with no improvement. Turned out to be the pick up coil. Even though an ohm test said it was ok I decided to swap it out anyway and was glad I did. $80 piece but saved me a trip to the dealers. Sometimes they only start acting up when hot so the ohm test would not tell that it was bad. Plus the problem was intermittent. The pick up coil is inside the alternater cover and the wire runs to a connection under the seat. A very easy fix but be sure to drain your oil first or it will come gushing out when you take off the cover.

When I was troubleshooting my problem awhile back, I had the alternator cover off to check the pickup coil. I had about a teaspoon of oil come out. I was on the sidestand however. I imagine if you are level on a jack, you will lose oil.

Tom:
Do you still have a part number? Here's the ignition schematic from Bike Bandit. Woudld the pickup coil be Part #1, called the Ignition Sensor?
Bike Bandit America Ignition Page

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I had the exact same problem at the beginning of the riding season. I went over all electrical connections and changed coils with no improvement. Turned out to be the pick up coil. Even though an ohm test said it was ok I decided to swap it out anyway and was glad I did. $80 piece but saved me a trip to the dealers. Sometimes they only start acting up when hot so the ohm test would not tell that it was bad. Plus the problem was intermittent. The pick up coil is inside the alternater cover and the wire runs to a connection under the seat. A very easy fix but be sure to drain your oil first or it will come gushing out when you take off the cover.

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Al, #1 is the pickup coil. If you are thinking about going after this, the easiest thing to do would be check the gap on it. Get a couple of gaskets in case you need to go back in.

btw, I am swapping back to the Nology coils this week (family room precluded this earlier). Would you like to borrow my stock ones for troubleshooting?

Phil:
Thanks for the offer, hang onto the old coils, I may take you up on that later this Fall. We're taking it on vacation next week (trailer...) and I don't want to open that up right now. When I return, it's due for an oil change, that would be a good time to trouble shoot.

Book isn't incredibly descriptive on checking the gap. Will it make more sense with the cover removed, looking at the assembly?
Did you use a little silicone to seal up the grommet? Any issues with that?

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Al, #1 is the pickup coil. If you are thinking about going after this, the easiest thing to do would be check the gap on it. Get a couple of gaskets in case you need to go back in.

btw, I am swapping back to the Nology coils this week (family room precluded this earlier). Would you like to borrow my stock ones for troubleshooting?

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It's very clear once the cover is off. Pull your plugs, leave it in neutral and on the sidestand. You will be able to turn it over using a BIG wrench on the the alternator rotor. Before removal, I also leaned it as far left as I could without dropping it to get as much oil out of that area as possible. Very little came out but I used tin foil as a 'duct' for the bit that did.

There's 4 lugs (wasted spark) sticking out of the rotor and I checked gap against all four (why not?). Mine was dead on 0.8mm.

It took me more time cleaning the stock gasket off of both surfaces than it did to check the coil!

There was silicon on the pickup coil and alternator output wire 'grommets' but mine looked to be in really good shape so I used none. I've run her good since then and I've seen no signs of any leaks. The 'grommets' have a mating surface similar the cam cover gasket if you know what I mean.

I put the new gasket on the motor side and wet a couple of spots with oil to keep it in place. It's dowel keyed so placement is easy. Just watch out when the cover gets close. The magnets in the cover are powerful enough to snatch the cover right out of your hands if you're not careful!!

So I'd need a new gasket as well, right? Since yours was in spec, you did not replace, correct? Just buttoned things back up, right?
Thanks for the descriptive, that helps a lot. Guess I better wait for the end of riding season, in case the wire is out of spec and needs to be ordered.

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It's very clear once the cover is off. Pull your plugs, leave it in neutral and on the sidestand. You will be able to turn it over using a BIG wrench on the the alternator rotor. Before removal, I also leaned it as far left as I could without dropping it to get as much oil out of that area as possible. Very little came out but I used tin foil as a 'duct' for the bit that did.

There's 4 lugs (wasted spark) sticking out of the rotor and I checked gap against all four (why not?). Mine was dead on 0.8mm.

It took me more time cleaning the stock gasket off of both surfaces than it did to check the coil!

There was silicon on the pickup coil and alternator output wire 'grommets' but mine looked to be in really good shape so I used none. I've run her good since then and I've seen no signs of any leaks. The 'grommets' have a mating surface similar the cam cover gasket if you know what I mean.

I put the new gasket on the motor side and wet a couple of spots with oil to keep it in place. It's dowel keyed so placement is easy. Just watch out when the cover gets close. The magnets in the cover are powerful enough to snatch the cover right out of your hands if you're not careful!!

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Mine tore a bit on removal of cover. Gaskets were cheap though!

I found no problems so yep, just put her back together.

The new pick up coils are a little different than stock and the part number has changed. The new ones are heavier wire and seem better than stock. I thought they sent me the wrong one because the rubber gromit is different but the dealer assured me it was correct and would fit. He was correct. I'm sorry I don't have the new part #.

Thanks guys. I won't be surprised if it looks slightly different (if needed at all).

Al,

I think I narrowed my problem. I was coming home from work today, and didn't even get out of the lot, and the bike started running poorly.

I pulled over and open the gas tank cap. It still ran rough. It died, so I started it back up and it ran fine.

I got it home and I replaced some vacuum line.

Came in and ate lunch and went out-- ran rough.

i disconnected the right plug and it ran rough, the same.
The i reconnected the right plug and discnnected he left. it wouldn't start.

No spark at the right plug. I put some dialectic grease in the cap and also at the coil.

it ran smooth.

so it's either the connection or the coil, right side.

let me your status,

cat

I’ve been having the exact same problem. Bike runs good then loses power, then after a few minutes it kicks in and runs fine. At first I thought it was a fuel related clogged fuel tank screen, vent line etc. Clean up the tank checked vent lines carburetor vacuum caps.

Well the other day when it did it again and I notice one of the plug wires going to the coil was lose and didn’t clip in tight. So I push it in snug and zip tied. I hope this does the trick

I put on new plug wires yesterday. Have her down at the beach this week. Not sure I'll get in enough miles to get hot enough for my problem to surface, but I'll see.

Hope your fix is that simple!

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Al,

I think I narrowed my problem. I was coming home from work today, and didn't even get out of the lot, and the bike started running poorly.

I pulled over and open the gas tank cap. It still ran rough. It died, so I started it back up and it ran fine.

I got it home and I replaced some vacuum line.

Came in and ate lunch and went out-- ran rough.

i disconnected the right plug and it ran rough, the same.
The i reconnected the right plug and discnnected he left. it wouldn't start.

No spark at the right plug. I put some dialectic grease in the cap and also at the coil.

it ran smooth.

so it's either the connection or the coil, right side.

let me your status,

cat

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