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Discussion Starter #1
My 1999 Adventurer has a chronic miss in the engine. I replaced the jets previously and have pods on the carbs and it has run strong in the past.

Before the last two times I cleaned out the jets and float valves, I had trouble with rust in the tank. Once I coated the tank, gas leaks stopped and the bike ran fine.

I suspect my problem is not in the carbs this time. I just cleaned them out and the jets looked OK. The bike took the throttle until about 2000 RPMs and then would break-up and stall.

I noticed today the right side cylinder ran cooler than the other two. Left and center pipes were 275 F. degrees, but the right pipe was 225 F. degrees. The temperature varied, but the right side pipe was always 50 degrees cooler.

I plan to change out the plugs, maybe switch the right and left plugs.

Does anyone have ideas?

Thanks,
Bonavent
 

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The pipe running cool is a dead giveaway that there is an ignition problem on that cylinder. To confirm it is a coil, switch around the coils to see if the problem moves to another cylinder. The original coils on these things are notorious for causing problems. Might consider replacing all of them if you don't have a history with the bike. Saves a lot of headaches. ...J.D.
 

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Discussion Starter #5
The right side exhaust pipe is still 50 degrees cooler after changing the coil, wire, and plug. I have 10.5 volts at the coil feed wires, same as other coils.

The engines misses at 2000 RPMs. Could it be a valve issue? Is it possible the right side carb is not getting sufficient fuel ? I see the ignition sensor wire at the crankcase has sealant on it. Would a bad sensor cause the engine to miss?

Thanks again,
Bonavent
 

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Normally if the pick up coil is bad it will run fine then when hot give up, which might be your prob since the bike is stalling. Bike will then usually start and run fine after it’s cooled down.
Certainly worth checking out the pick up coil and resetting the gap.
You said you had issues with rust previously and you don’t think it’s fuel issue but did you check the little witches hat filter at the carb?
 

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The voltage at the coils is kinda low. Should be above 12. Check your battery and alternator output. This could be causimg some of your problems. I would certainly check in to valve clearance as well.
 

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Discussion Starter #8
Thanks again.

The battery is a year old. I charged it yesterday and voltage today was 12.5 volts. Voltage at the coil feed wires read 10.9 volts.

I assume the witch hat filter (duckbill?) resides at the point where the fuel line connects to the carb bank. It was missing.

For some time, yesterday the right side exhaust pipe was cold. After I changed the coil, wires, and plugs around, the cylinder was firing, but still runs 50 degrees cooler than the others.

Before I check the valves and pick-up coil, I'll check for a voltage drain somewhere, ensure the right side carb is getting sufficient fuel, and then switch jets around on the carbs.

I have been cleaning the jets with a piece of wire from a wire brush, done gently I think, but may have scored a jet. I've been doing that all along especially when I had the rusty tank problem. I don't think that's the problem.

I appreciate expert thoughts and time taken to respond.

Thanks, Bonavent
 

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Discussion Starter #10
This forum has been great help. Thank-you.

I'm almost ready to replace the igniter. I read 11.5 volts at both leads feeding each coil which is puzzling to me.

It also appears sources for igniters are OEM from Triumph or the Czech version.

Thanks again.
Bonavent
 

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I'm almost ready to replace the igniter. I read 11.5 volts at both leads feeding each coil which is puzzling to me.
That could cause it to not run, but wouldn't cause a miss. The igniter works like a set of ignition points. Then the "points" are open you'll see the same voltage on both sides of the coil. When they are closed you'll see (near) zero volts on the negative side and 11.5 or whatever on the plus side. If you're trying to read it while the engine is running all bets are off.
 

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Discussion Starter #12
I understand, thank-you.

ACV on the negative side of all the coils reads .29 ACV.

I'm still searching for a conclusive way to determine if the igniter is good or bad.

The engine breaks up pretty badly at RPM>2000. The right side exhaust pipe is consistently 50 degrees cooler regardless of the temperature variation.

TY,
Bonavent
 

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It's not AC, it's pulsed DC. You can use a frequency meter or a dwell meter or a duty cycle meter. The frequency meter should vary in proportion with RPM. The other two will give you a (steady) reading somewhere between zero and 100%. (If it reads either 0 or 100 something is wrong.)

Regardless, I wouldn't expect the igniter to cause a miss. I would expect it to cause one or more dropped cylinders.
 

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When my igniter went south the center cylinder dropped out completely, occasionally run again but progressively got worse until it wouldn't start. no miss firing just no firing.
 

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Discussion Starter #15
Thanks, I appreciate the responses. I have more than a miss in the engine; it breaks up pretty badly.

I had difficulty fitting one of the outside carburetor diaphragms, so I'm going to pull the carb bank & maybe change jets around too.

The cylinder wasn't firing at all just one time, other wise, the only difference is lower temperature by 50 degrees.

It seems like the igniter would fail completely rather than get progressively worse before it failed. I suspect my bike won't start either and I'll be replacing the igniter too. In the meantime, I'll keeping testing and locate a duty-cycle/dwell/frequency meter.

Thanks again,
Bonavent
 

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My legend was acting the same as your bike misfiring on one cylinder every now and again it would kick in long story short it turned out to be the igniter replaced it problem solved
 

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While reading through the string, I didn't see if you changed around your plug wires.
If they are the original wires, you could have one either breaking down, or a poor connection.
If you haven't already, do a resistance check on the wires, get a flashlight and look at the internal connecting clip at the base....etc.
I like to put a dab of dielectric grease on the boot connector interior to keep out moisture, and ease installation.

Good luck,

Dan
 

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I'm still wondering about the low voltage readings at the coils. If your primary voltage is low, your secondary voltage will be very low. Garbage in- garbage out. ...J.D.
 

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Discussion Starter #19
Thank-you. I changed the coils and plug wires around and the temperature deficiency remained on the right side cylinder. I have a greater problem because how badly the bike runs. I've ordered the igniter from Ignitech.

After I charged the battery, voltage increased at the coils to over 11 volts. I've also ordered an Interstate AGM battery for the bike.

Much appreciated,
Bonavent
Gainesville, FL
 
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