Problem with 4th Cyl...

Hello again everyone...I have this problem in the 4th Cyl. (the right one sitting on the bike). Thing is that after 2 or 3 miles the cyl stop working...I change the spar plug and start working again for another 2 to 5 miles. Seems that when the spark plug heats up it stop to make the spark. So I changed for a hotter one (#12) but still the same problem shows up only this time it last like 8 miles running ok. Spark plug is clean, no black, or oil, nothing. Someone told me is running too rich... what do you thing is the problem here?

 

are your spark plug caps (boots) resistor caps could be the resistor inside of them is failing when it heats up , switch boot 1 with 4 and see if the problem follows the cap .
thete is a screw inside of the cap which could be loose tighten it up a little if it is.
oem caps have resistors and a spring inside which could fail

 

That sound good...I never thought about it...I'll do that...and see if the problem follows

 

Seems that does not work... when engines is hot (after a 7 miles ride at 60mph) the spark plug seems to fail to make the spark and the 4th cyl stop working. Changed spark plug and everything is back to work again. It a matter of how hot is the engine or the cyl. That does not happens in short ride over the town...I just ran out of ideas here..

 

1/4 coil may have a bad #4 lead

 

#4 spark plug may have been bad.

 

K-moe is not the spark 'cause I keep change it and the next one works well until it heats up again

 

Hogfiddles...by the "coil" you mean the cable that connect the ignition coil with the spark plug cap? by the way this cup screws into the cable? or is just one piece?

 

I think it's fouling that plug. Float sticking in #4 carb. Reason a new plug fixes it for a short while, and also why the hotter plug lasted a hair longer.

 

"I think it's fouling that plug. Float sticking in #4 carb." I think that could be it, that why next week my mechanic is going to check the carbs, gaps in valves and everything, It sucks stopping every 5 miles to change sparks, but I do not have the time and most important, the tools or place where to work in the bike... Last time of carbs sync was 2 years ago...

 

Te cap does screw on to the cable. When you remove it you will probably find corrosion on the wire. Just cut it back a cm or so, and put the plug cap back on.

 

ok..thanks!!

 

I recently had a similar problem with my ignition system. i replaced the coils and wires due to infinite resistance, the bike did run better but some days would okay and some would run poorly. i ended up swapping out the ic ignitor box and fixed problem. i was too having the number four plug fouled and covered in gas. not sure why it did not do the same to 1 though. maybe you could wire up a test light to the coil and see if the signal is cutting out to fire the coil when the problem is happening

 

What you mean by "i ended up swapping out the ic ignitor box"??

 

guys...i found out that that cyl 3 and 4 are heating up a little more that 1 and 2...