Low Rpm st-st-stutter

drbone641 · Post by **drbone641** » Wed Jun 18, 2008 7:04 pm

My 82 runs really rough below 3500-4000rpm. After it goes above that it sounds like a CBX ought to. Before I start tearing into carbs etc I was wondering if anyone had any other ideas. I have braided plug wires which I am suspect of. Is there a chance they are leaching spark until the rpm get high enough??? Anyway thanks for any ideas.

Terry · Post by **Terry** » Wed Jun 18, 2008 7:35 pm

I also have Taylor braided wires on my 79 and to check them I fire it up in the dark. So far, no sparking anywhere, and that's even after I found rat bite marks on the plug caps!

CBXRoger · Post by **CBXRoger** » Wed Jun 18, 2008 11:11 pm

A small infared temperature sensor shined on the exhaust pipes after a short ride at the stuttering RPM will point you in the right direction. If you have two cylinders that are cool and they share a coil, it might be an ignition problem. If the number of problem cylinders are one, three, five, I would look at fuel system. With the temperature sensor, you have a starting place to look for your problem.

drbone641 · Post by **drbone641** » Wed Jun 18, 2008 11:25 pm

will the higher rpm overcome the bad coil to make the engine run right?
My first thoughts were carb related, but before I start throwing time and $$$. New Coils/wire @ $219 is definetly the cheaper way to start.

alimey4u2 · Post by **alimey4u2** » Sat Jun 21, 2008 2:43 pm

drbone641 wrote:will the higher rpm overcome the bad coil to make the engine run right?

I doubt if that is the case...Find the cold cylinder/s at the low rpm range & stick a timing light on the HT wires to look for a regular beating spark. Then check valve clearances before diving into the carbs ( it's easier.)

bobber · Post by **bobber** » Sat Jun 21, 2008 5:35 pm

How is the bike at idle? If a bit rough try removing plug wires to see if engine idle changes much. If 4 make a big difference while two don't may be able to help pinpoint if the two use same coil.
Also, do the plug caps have built-in resistors? I'm not sure for the CBX however have experienced failed resistors on snowmobiles.