Is This Normal?

[AndyJ]

Is this normal?
Bike was running beautifully several weekends out, then one day began misfiring on the right side. Right side plug looked fouled, I though a fresh spark plug would solve the problem but didn't.
I noticed when the plugs were out that both cylinders have spark however when I turn on the ignition for a couple seconds, then off, the right spark plug makes an arc… I switched the left and the right coils to see what happens and it still continues on the right side after turning off the ignition. This also occurs only on the right side after I kick the engine over (both sides spark at the same time when kicking then 2-3 seconds later the right side sparks)
The bike still starts up on first kick, idles smooth and even revs pretty good in neutral. As soon as it's put into gear and under any type of load it starts misfiring and running rough.
I've switched out the ignition control module from another running bike and that's not the problem. Valves and timing all seem to be ok.
I'm at a loss and can't figure where the problem is. Can someone please tell me if this "extra spark on the right side is normal"?
If so, then I need to look further into the engine.
It's a 1981 model.

Thanks for all you help and input.
Andy

 

[xschris]

If your fouling plugs it sounds like a fuel issue. Never kick the bike over without grounding the plugs. This can kill a tci box or coils. Post some pics of the bike so we can see what you are working with.

 

[AndyJ]

Hi Chris,

Thanks for your reply.

The plug was slightly fouled, it's definitely getting fuel. The bike starts and runs, revs etc. right cylinder cuts out when trying to ride.
Can someone confirm if it's normal for the right side to spark after the key is turned off?
I always ground the plugs when checking for spark and noticed after checking for spark and turning off the key that the right side gave another arch a few seconds after.
This is a mystery to me, but if it's normal I can move on to other possibilities.

Thanks again.

 

[xschris]

Fouled plugs are a carb issue. A sparking plug with the bike off could be a wiring issue. If the plug sparks with the motor not moving you could be getting voltage to the coils when you should not be. Could be out of sync carbs for the popping. Did you sync them with a manometer? Is the bike all stock? If you have modified anything it could be lots of things. Customs bike have custom problems.

 

[AndyJ]

The bike has run very strong a couple hundred miles on this set up, small battery, no electric start and red/white wires connected.

 

[drewpy]

ahh the dreaded blue connectors, never use them on a bike always crimp with multi plugs or bullets.
they are OK in a car but not exposed on a bike

 

[xschris]

What about the carbs? Are they clean? Are the diaphragms in good shape? What air filters and exhaust are you using?

 

[AndyJ]

My set up was running 110% with properly jetted Mike's XS carbs and Banshee cable..
I confirmed the bowls have fuel, can see light through both main and pilot jets..
initially I thought it was carbs but after a quick check, which is super simple the jets are all good.

Drewpy, I agree about the blue connectors it's only being used to cap off the blue wire (I couldn't find my electrical tape)

I'm going to check the timing again but don't think that's it either. I set it perfectly a couple hundred miles ago.

Can anyone let me know if their right side spark plug sparks after turning off the ignition?

Thanks guys!

 

[BBS360]

I think Dave mentioned in another thread that the TCI turns off after a period of no activity?
This would cause a spark.

 

[AndyJ]

 

[AndyJ]

I think Dave mentioned in another thread that the TCI turns off after a period of no activity?
This would cause a spark.

Ok, thanks for your reply.
I wasn't sure if that's what Dave meant. So I guess it's normal to only spark on one side after turning of the ignition.. strange thing is that it also lets off another spark a few seconds after kicking over, I guess this is the TCI shutting down.
I probably need to check compression at this point.

 

[xschris]

How did you sync the carbs if you don't have any air barbs on the intake manifolds? To set timing correctly the motor needs to be running at 1200 rpm. I see no tach on the bike. How did you do this.

 

[AndyJ]

Bench synched, then fine tuned when running by adjusting cables until idled and revved smoothly. The bike was running very good, super strong even scary crisp throttle response for several hundred miles and gradually began to misfire on the right side.

I've been reading up on some compression issues and beginning to think maybe a valve is stuck.. also, last night I pulled the right exhaust header and noticed it was very loose.
Checking compression today.
Thanks!

 

[xschris]

Others have had issues with the cheap components these have inside. A sync with a manometer is the only way to get them correct. Trust me

 

[AndyJ]

Others have had issues with the cheap components these have inside. A sync with a manometer is the only way to get them correct. Trust me

Thanks Chris,
I have a set of vacuum gauges but couldn't find any place to attach them, does a manometer attach differently?

Timing was spot on at idle and through the low rev range. I realize it's not a very technical or scientific method but as I previously mentioned the bike had been running 110%

 

[Ezetman]

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Not to deviate from the conversation but I can't resist on commenting how beautiful that motorcycle looks man! Plus I am also in florida and those dunes? look fun.

 

[AndyJ]

Not to deviate from the conversation but I can't resist on commenting how beautiful that motorcycle looks man! Plus I am also in florida and those dunes? look fun.

Thanks man!
That area is in SW Palm Bay
We live in Vero Beach.

 

[xschris]

A manometer is the most accurate way to sync. Look up on google what they are. The stock carb boots have barbs for this. There are old style types that go into the mouth of the carbs to measure vacuum. If you never ran the bike with the oem carbs and synced you wont know how was made to run. Bench sync is to get the bike to run and that is it. With your bikes' setup you may have to chase your tail for a while to get it all figured out. Too many unknowns the way it is.

 

[AndyJ]

Since I've got the Mike's XS set up there are no barbs on the intakes.. but there are several other orifices on the carb bodies with vent tubes..
Thinking I may drill and tap holes on the aluminum intakes to install barbs.
Just stumped because the bike was running beyond perfect a few weeks ago and I hadn't used any meters to synch the carbs.

 

[Jeff0133]

Bench synched, then fine tuned when running by adjusting cables until idled and revved smoothly. The bike was running very good, super strong even scary crisp throttle response for several hundred miles and gradually began to misfire on the right side.

I've been reading up on some compression issues and beginning to think maybe a valve is stuck.. also, last night I pulled the right Jesse and noticed it was very loose.
Checking compression today.
Thanks!

Read on here somewhere that misfiring when warmed-up was maybe a TCI issue....