Misfire??

[jimmy99]

My venture started running on 3 cylinders a few days ago.

The fourth on "kicks" in around 4000 rpm intermittently and it runs solidly on all 4 above 4600 rpm.

 

I tried replacing the spark plugs with new ones but it made no difference.

I'm not sure if the problem is spark or carb related and am even having trouble deciding which cylinder is the problem.

I am heading out to the garage to once again start it and try to figure out which one warms up the slowest.

 

If anyone has experienced this before I would be very interested in knowing what solved it.

 

Jeff

[jimmy99]

Well, the carbs are out. I took the air filter out n looked inside and saw that the needle tube on carb 3 was out of place.

I got it set back in and tightened the holder screw and have the carbs ready to go back on the bike but that will have to wait until tomorrow.

Have to work early tomorrow n must get some rest.

 

Hopefully this his will solve the problems

[bongobobny]

Hope that fixes you problem!! The other common issue for this is the TCI...

[diversity48]

A sure sign of the tci failure is if the tachometer quit working while it was missing.

[bongobobny]

A sure sign of the tci failure is if the tachometer quit working while it was missing.

Not necessarily. Only if it is #2 misfiring, or the whole thing (all 4) goes south. If the failure is on one of the other cylinder circuits, the tach will still keep working...

[jimmy99]

It was carb related. I had to open up carb 3 and re-secure the needle tube. The screw that holds it in had come loose.

The bike is back to running on all 4 all the time.

 

I also adjusted the carb needles moving the clip down 1 groove to richen the mixture. The plugs were a little light looking.