[alski425]

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A problem for me. Hey guys I need your help. While idling my bikes engine skips a beat. I traced it down to number two cylinder. It fires a few times then skips a beat, fires again afew times and misses etc: I changed the sparkplug it does the same. Could a coil do this? I am at odd ends trying to figure this out .I really need your help. Thanks ahead of time.

Alski

 

[Tonys96]

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What year is the bike ???

A coil would usually affect 2 cylinders.

Could be a high tension lead (spark plug wire) or ???

Is the #2 plug wet, black, light tan same as all the others ???

 

[twisty]

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alski425 wrote:

A problem for me. Hey guys I need your help. While idling my bikes engine skips a beat. I traced it down to number two cylinder. It fires a few times then skips a beat, fires again afew times and misses etc: I changed the sparkplug it does the same. Could a coil do this? I am at odd ends trying to figure this out .I really need your help. Thanks ahead of time.

Alski

Alski, if it runs good & pulls under throttle without any missing then I seriously doubt it's ignition related (usually an ignition or spark plug problem shows up most under a load).. Usually when you have an erratic idle it is either a vacuum leak or an idle mixture problem..

First thing to do is make sure the carbs are properly synced to each other.. At low idle the carb mis-synchronization shows up the most.. If OK there, then look for a vacuum leak or an improperly set idle mixture.. Do an idle drop setting on the pilot needles, then after set by the book, open the needles another 1/4 turn or so..

You could possibly have a sticking valve at idle but I'm betting on a lean idle mixture on that cylinder..

Twisty

 

[alski425]

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Twisty and Tony

Heres whats been done. The bikes a 1987 Asp. 1200. I bought it June 1 st. The guy I bought it from put 2300 miles on it in 10 yrs. none in last 4. It started but barely. I did the carburators took them out 4 times in fact. there has been this miss , you donthear or feel it at high rpm. Today I put a timing light on each indivdual plug wires. All were flashing ok except #2 cyclinder. I just got done exchanging plug wires. samo samo # 2 misses a single beat every so often with differant plug wire. so its not the wire. The engine idles nice. I have sync. the carbs. new plugs. all plugs look the same after running. I have put 1000 miles with this condition. But would sure like to cure the problem. Thanks for the replys guys.

Alski

 

[BRowan]

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Next step is to swap the coils over and see if the miss occurs on another cylinder. If it does then its coil related. If the miss is still on the same cylinder then it could bethe pulse generators.

 

[Wendell]

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You might want to check the hard plug boot too. If it is cracked, it could jump to ground, thus allowing that cylinder's sister to fire as it should. Try running it in the dark and take a looksee. If it is bad enough, you'll see a bluish arch. Or take a 12v light tester, attach it to a ground andmove the probe end against and around the boot. If there is a crack, it may jump to the tester and cause the miss. Another way is to use a small spray bottle filled with water and lightly mist that plug boot. That will find a crack for sure. Also, if you can remove the rubber piece that ties the two plug boots together, use a good light and take a close look in the covered area and do one of the tests listed above. Good Luck!

 

[Wendell]

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You might want to check the hard plug boot too. If it is cracked, it could jump to ground, thus allowing that cylinder's sister to fire as it should. Try running it in the dark and take a looksee. If it is bad enough, you'll see a bluish arch. Or take a 12v light tester, attach it to a ground andmove the probe end against and around the boot. If there is a crack, it may jump to the tester and cause the miss. Another way is to use a small spray bottle filled with water and lightly mist that plug boot. That will find a crack for sure. Also, if you can remove the rubber piece that ties the two plug boots together, use a good light and take a close look in the covered area and do one of the tests listed above. Good Luck!

 

[Wendell]

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:shock::shock::shock:Is there another echo in the room??:shock::shock::shock: