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Low Rpm st-st-stutter
Posted: Wed Jun 18, 2008 7:04 pm
by drbone641
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.
Posted: Wed Jun 18, 2008 7:35 pm
by Terry
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!
Posted: Wed Jun 18, 2008 11:11 pm
by CBXRoger
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.
Posted: Wed Jun 18, 2008 11:25 pm
by drbone641
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.
Posted: Sat Jun 21, 2008 2:43 pm
by alimey4u2
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.)
Posted: Sat Jun 21, 2008 5:35 pm
by bobber
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.