I think these carbs are having an ignition problem ....

[TopCatGr58]

Hey Barbarosa,

Scott has got you well sorted. IMHO, I think you may be flogging a dead horse with regards to the ignition coils. They are 36 years old! They have gone thru thousands of heat up/cool down cycles. Granted, there aren't any MOVING parts in it, but heating up cycles still wears on the windings. The coils may just be worn out...and remember, they only generated ~15Kv at best NEW, and that's at the full Starting 12v's, so it's definitely gonna be weaker sucking ~9 volts thru the ballast resistor.

Folks have chased low rpm misses and stuff with these OEM coils, and finally after putting in either newer Honda VF1000 coils, or New Accel/Dynatek High Output(35KV) coils, bypassed the ballast resistor, and their low rpm miss/fouling went away!

Sounds like you've tested the heck out of your system, and Scott has confirmed that you really aren't missing that much voltage and the bike does run when you're not just idling it, but when you're trying to tune it at idle, the OEM tired coils just can't produce enough spark energy to keep the plugs firing properly, the ALT doesn't produce enough volts at idle to keep the battery charged.

I think it was Brant/Motoman that chased a low rpm miss problem thinking it was carbs, until he replaced his coils.

JAT! T.C.

[motoman]

Hey Barbarosa,

Scott has got you well sorted. IMHO, I think you may be flogging a dead horse with regards to the ignition coils. They are 36 years old! They have gone thru thousands of heat up/cool down cycles. Granted, there aren't any MOVING parts in it, but heating up cycles still wears on the windings. The coils may just be worn out...and remember, they only generated ~15Kv at best NEW, and that's at the full Starting 12v's, so it's definitely gonna be weaker sucking ~9 volts thru the ballast resistor.

Folks have chased low rpm misses and stuff with these OEM coils, and finally after putting in either newer Honda VF1000 coils, or New Accel/Dynatek High Output(35KV) coils, bypassed the ballast resistor, and their low rpm miss/fouling went away!

Sounds like you've tested the heck out of your system, and Scott has confirmed that you really aren't missing that much voltage and the bike does run when you're not just idling it, but when you're trying to tune it at idle, the OEM tired coils just can't produce enough spark energy to keep the plugs firing properly, the ALT doesn't produce enough volts at idle to keep the battery charged.

I think it was Brant/Motoman that chased a low rpm miss problem thinking it was carbs, until he replaced his coils.

JAT! T.C.

Yup.......replaced with Honda VF coils.......plug/mount and play. Mounting on frame locations same,same.(take ohm meter with you to check ohms across both poles before purchase)

[Barbarosa]

!2v is all I have ever looked for on a bike ignition. Most of the time it was by sticking a screwdriver in the points. So does a 40000v coil always put out 40000v regardless of the amount of voltage that powers it up? Anyway, there is nothing major wrong with this motorcycle. I can't vouch for what's inside the shrink wrap and tape in the wiring system, but the rest of it is well up to standard. May put out an APB for info lol. It's not that I'm looking to get back on the carbs though.

[Barbarosa]

Yup.......replaced with Honda VF coils.......plug/mount and play. Mounting on frame locations same,same.(take ohm meter with you to check ohms across both poles before purchase)

You guys read my mind on the coil thing. Anyone know of a bone yard close to Fayetteville, AR lol. Probably best for me to do mail order since it's $5 in gas for me to go to town and get back. Was really hoping to be able to make it run before replacing parts that test in spec. but it is the logical next step. Thanks for making my mind up for me.

[DAVINCI]

Stan, I replied to your message. take a look and get back to me

[3Phase]

Do it!

I don't believe the ignition coils or the TCI or anything else to do with the electrical system is causing the plugs to foul but getting better coils is never a bad idea. Go for it!

.

[Barbarosa]

Ordered a set of dynas from feebay. Pulled the trigger at $108. Bet it would have ran just fine without yanking the carbs though. Guess that's why hindsight always costs more. Real familiar with XS fuel and ignition systems now lol. Hope I don't have to learn too much more before this thing gets to running.

[TopCatGr58]

Okay, just hoping you made sure to get the 3.0 ohm style? Also, the coils don't come with the actual PLUG wires or caps. You'll want to get SOLID core wire, 7mm or 8mm. Since most folks say they usually get Resistor plugs, you don't need to get resistor caps. The resistors are just for reducing radio frequency interference which doesn't affect the TCI on our bikes, but can be bothersome to folks with AM radios!

Folks have gotten a cheap 4 cylinder set of wires from the local auto parts dealer to be able to get the type of connectors and boots for the plug wires where they fit into the coils. The coils have the recessed fittings sections just like automotive coils. I just took the connectors off of the cheap wires to put on the Solid core ones. I think they do sell a complete Wire/connector kit for the Dyna's, but I wanted to fit mine quickly using local supply vs. waiting for parts to order. I already had the Solid Core wires and caps from my previous crappy Mike's XS coils, so just needed to the connectors to fit the coils...the Mikes used just screw in similar to the caps.

And as to the power, there will be variable amounts of output from the coils depending on the amount of voltage going in, but they are designed to generate over twice the Kv energy of the OEM coils, and on ~12V all the time, so the potential for full power all the time as well. And so if/when the coil voltage drops to around 11V, you'll still be getting much more Kv power to the plugs vs. the old OEM's running on 9 or less volts.

T.C.

[skids]

Hey Barbarosa,

(snip) The coils may just be worn out...and remember, they only generated ~15Kv at best NEW, and that's at the full Starting 12v's, so it's definitely gonna be weaker sucking ~9 volts thru the ballast resistor. (snip)
T.C.

I has a set of coils that gave me fits. I found that when they heated-up the resistance went way up. They were only about 20% too high when cold.

[skids]

I don't believe the ignition coils or the TCI or anything else to do with the electrical system is causing the plugs to foul but getting better coils is never a bad idea. Go for it!

.

It seems like failing to fire consistently would cause fuel fouling not fluffy carbon fouling.

[3Phase]

It seems like failing to fire consistently would cause fuel fouling not fluffy carbon fouling.

That was my thought too but we'll see what happens. (popcorn-eating smiley)

.

[Barbarosa]

Maybe with the hotter spark it will take longer to foul out the plugs. I'll just carry 3 sets and only ride to the Sonic. I'm counting on 1 mpp since it's a 12 mile round trip. Only taking that extra set just in case. This is my first go around with having a problem with multiple carbs (if that is the real problem) and I can't believe they are so persnickety. Have had coil problems soot up plugs before but it happened over time and I wasn't troubleshooting machines I didn't know and ride. This one started acting up off right out of the box and since it had been setting it's usually SOP to clean the fuel system. Have a set of DC1-1 Dynas on the way and it they don't do the trick I guess it's time to start tweaking floats again.

[bikerphil]

Just wondering if you have those transitional 80 carbs that require the rubber plug over the pilot jet tunnel. If they have the crossover passage and are being run without the blockoff plugs, you will have an overly rich condition. JAT

[Barbarosa]

That was my thought too but we'll see what happens. (popcorn-eating smiley)


.

I believe the firing is consistent, but too weak to burn off all the fuel. Any rich carb conditions I have corrected started with fuel fouled plugs and they were mechanical in nature and easy to correct. A single carb motor will practically tell you what's wrong with it though. Hope the coils make it feel better at least.

[Barbarosa]

Just wondering if you have those transitional 80 carbs that require the rubber plug over the pilot jet tunnel. If they have the crossover passage and are being run without the blockoff plugs, you will have an overly rich condition. JAT

You and me both now lol. No, I don't believe so. I remember seeing a picture of the crossover detail and it didn't look the same as these.