Something is amiss

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Trondyne

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Sep 30, 2017
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Location
Pelham, NY
Trying to diagnose this problem...

Cylinder number 4 I think? Right side, rear...is missing...

At idle it fires about 1 in 4 or so, it varies quite a bit and then tends to fire regularly after RPMs get over 2,800... Occasionally that cylinder will stop firing completely, this can last from a few seconds to a few minutes... When it starts to fail completely giving it wide open throttle will exacerbate the problem and often cause the cylinder to cut out...

After changing the plugs it got a little better (before that it was backfiring form same cylinder) but not much and after putting some Seafoam in the tank it got a little better but not much.... A long ride also seemed to help a little and during highway speeds the motor ran just okay with poor fuel mileage and slightly reduced pull..

Another symptom is a strong gas smell while idling and/or first starting ....and some spitting...

The two things that pop into my head are carburetor problem(s) and or a coil problem...

My next move was going to check to see if the spark is regular on that cylinder ...

Any ideas would be much appreciated..
 
Thanks for the numbers... So, this is #3...

No, I didn't check the float levels...

I have no idea how that's done...

So, do you think the float might be too high allowing too much fuel into the bowl?

Or might be stuck open?
 
http://vmaxforum.net/showthread.php?t=17274

Try the link above.
If you have a manual, it details on how to check the wet float level.
Its possible the float is sticking or way out of adjustment.

While your at it, drain the bowls into a clear glass container and see if the fuel comes out clean.

Its also possible that cylinder isn't firing properly. You can swap coil, caps, and plug wire on the rear 2 cylinders and see if the problem moves.
 
http://vmaxforum.net/showthread.php?t=17274

Try the link above.
If you have a manual, it details on how to check the wet float level.
Its possible the float is sticking or way out of adjustment.

While your at it, drain the bowls into a clear glass container and see if the fuel comes out clean.

Its also possible that cylinder isn't firing properly. You can swap coil, caps, and plug wire on the rear 2 cylinders and see if the problem moves.

I'll check into that, but my ability to do major carb work is limited...

Interesting, so the fronts and rears fire at the same time...?

Well, I just took the bike out and it was sitting in the rain for a bit this morning.. In the wet the cylinder was not firing at all...or once in a while...

She never had trouble in the rain before....
 
To wrap this up....

One of the ignition wires fell off when I was moving it around...

When I checked the coils under the seat I found that the conductor in one was about a half inch away from the end of the insulator, (how does that happen?) the other was down about 2mm...

So I sripped the isulators and fabbed a donut to hold one cap on that fell off...

The coils were cracked and on one I could feel the voltage, so I sealed and covered that side with epoxy, (couldn't find the silicone..)

Results are -- now running on all 4 cylinders instead of 2 or 3... One cylinder is still missing about 1 in 5, much better than 5 misses to 1 fire at low rpm ...

Power is good and much more stable but some new popping and backfiring occasionally when cold...but went away for the most part...

A big relief and she's with her power back to around when I got her at the end of last season...

Now I can wait until I get the cash to do the full tune on the bike....

Thanks to all for the help...
 
Ask members for a pair of coils from someone who did the COP coil-over-plug conversion, or if someone has a pair that look decent from a part-out, the coils are usually cheap, or free.
 

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