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A65 stuttering at speed
#775516 06/03/19 10:46 am
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Going crazy here.
So my lightning has a stuttering/lugging problem at about 3/4 throttle, around 4-4.5k rpms im guessing (no tach). It had been running good but after rebuilding the carbs it boggs down and stutters right about the point it should be taking off then as the rpms (painfully) increase it clears out and accelerates as it should.
Ive replaced inline fuel filters, pulled the carbs apart again and gave em a good spraying with carb cleaner, played with air/fuel mixture, dropped the needle, raised the needle, just bout everything i can think of and its making me nutters..
Oh, new battery, ignition switch and running pazon e.i. for reference.
Originally pulled the carbs cause i assumed original problem i was chasing was from the carbs sitting for a couple months woth fuel in and getting gummed up but was the failing battery.
What am i missing here?

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Re: A65 stuttering at speed
drunkenmonkz #775519 06/03/19 12:20 pm
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what happens if you have the bike in a lower gear and rev the engine through?


What do the plugs look like?

If you had said that the stuttering doesn't clear then i would have suggested the main jet has come loose or worse, come unscrewed and dropped into the bottom of the bowl (this can happen)

From experience, its most likely a coil issue but need info as above.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 stuttering at speed
Allan G #775524 06/03/19 1:32 pm
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Originally Posted by Allan Gill
what happens if you have the bike in a lower gear and rev the engine through?


What do the plugs look like?

If you had said that the stuttering doesn't clear then i would have suggested the main jet has come loose or worse, come unscrewed and dropped into the bottom of the bowl (this can happen)

From experience, its most likely a coil issue but need info as above.



It acts the same through all the gears. I was hoping for a loose main or something... but everything was righty tighty
Plugs are new and looked okay after running a bit but reading plugs is like voodoo magic, i dont understand how it works, it scares me a little and im likely to hurt myself or someone else so i try to stay away from the dark arts..

Re: A65 stuttering at speed
drunkenmonkz #775528 06/03/19 2:16 pm
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what make are your coils/ coil(dual?)? do you have a spare (or one from another bike) which you can try?

as for the plugs, a simple they are black or bone white or "nice tan colour" would suffice, just a quick indicator as to if the mixture condition is very rich or very lean.

Last edited by Allan Gill; 06/03/19 2:25 pm.

Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 stuttering at speed
drunkenmonkz #775531 06/03/19 2:26 pm
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How old your needle jets are ?
They are wearing out quickly.

Re: A65 stuttering at speed
drunkenmonkz #775532 06/03/19 2:34 pm
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You have new electric parts, is the fuse the glass cylinder type or a blade, the glass type can do weird things with vibration. The fault you describe sounds like a bad connection somewhere, A hot wire from natt terminal to pazon will quickly rule this in or out.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: A65 stuttering at speed
Allan G #775536 06/03/19 4:03 pm
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Originally Posted by Allan Gill
what make are your coils/ coil(dual?)? do you have a spare (or one from another bike) which you can try?

as for the plugs, a simple they are black or bone white or "nice tan colour" would suffice, just a quick indicator as to if the mixture condition is very rich or very lean.




Not sure on coils brand. Bought them with the pazon few years back. Ill hunt for a spare. Plugs are tan/coffee color.

Re: A65 stuttering at speed
gavin eisler #775539 06/03/19 4:07 pm
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Originally Posted by gavin eisler
You have new electric parts, is the fuse the glass cylinder type or a blade, the glass type can do weird things with vibration. The fault you describe sounds like a bad connection somewhere, A hot wire from natt terminal to pazon will quickly rule this in or out.


Blade type. Ill have to check connections again..

Re: A65 stuttering at speed
Adam M. #775540 06/03/19 4:09 pm
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Originally Posted by Adam M.
How old your needle jets are ?
They are wearing out quickly.


Needle specs oit good and shows no signs of wear.

Re: A65 stuttering at speed
drunkenmonkz #775598 06/04/19 6:22 am
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If you bought your coils from Pazon it is likely that they are PVL, which are about the best traditional style coils you can get. I bought some when I first got my bike on the road, looked identical to the pvl but weren’t and were cheaper. One failed after 300 miles. The both got replaced by PVLs and I never had another moments trouble, although the fault itself was had to track at the time. Like yours it would only happen at certain points.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 stuttering at speed
drunkenmonkz #775651 06/05/19 3:03 am
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Think i got it figured out. pazon wire was just loose enough on the coil to lose continuity while at the same rpms through all the gears. Tight enough to run great at idle and city cruising but the vibrations were enough to make it bounce around and feel like a fuel delivery issue.
Fingers crossed it is the issue. Short round the block couple times felt good..
Thanks y'all

Re: A65 stuttering at speed
drunkenmonkz #775657 06/05/19 6:26 am
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If not do as Gavin suggested a while back.
Hard wire the pazon to the battery bypassing the ignition switch.
The BSA switches are not that great which is why I opt for ignition relays rather than running everything through the switch.


Bike Beesa
Trevor
Re: A65 stuttering at speed
drunkenmonkz #775668 06/05/19 10:24 am
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If your using spades, switch them to ring terminals and fit serrated washers under the nuts.

Which reminds me I really aught to loose some of my jumper wires on mine.....


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: A65 stuttering at speed
drunkenmonkz #775673 06/05/19 11:35 am
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Alternatively use pliers to nip up the gap in the spades so they grip better, well for a time anyway, ring terminals are a more permanent fix.

Re: A65 stuttering at speed
kommando #775677 06/05/19 1:17 pm
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Originally Posted by kommando
Alternatively use pliers to nip up the gap in the spades so they grip better, well for a time anyway, ring terminals are a more permanent fix.


You can get female spades with locking tabs (which is why male spades have the little holes in)


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)


Moderated by  Allan G, Jon W. Whitley 

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