69 norton commando running poorly when riding.

my 69 commando about 200 miles on rebuild was running great got the carbs tuned pretty good. boyer ignition newer plugs. starts first kick ides great responsive at idle. when you put into gear and go under load it has no power won't rev acts like you've hit a rev limiter. the headers are both an equal brown color so shouldn't be lean about 1 1/4 turns out. on fuel mixture. could it be the ignition breaking down. voltage at idle is 15 volts. this has got me stumped and it has new amal 932.

Hi buddy,

Good show with the 69 ,my favourite . 200 miles is only a good shakedown , I've got no idea what's up,as you've probably changed the plugs ,checked the Boyer is tight on the cam and strobed the timing etc. There will be guys on here that will suss it out PDQ , best of good luck to you.

Jg

Hi.
Take a control to the throttle idle than can have lost the clip and close the fuel.
To me happened.
Easy to check, remove the float bowl and main jet.
Ciao
Piero

ZRMiller said:

my 69 commando about 200 miles on rebuild was running great got the carbs tuned pretty good. boyer ignition newer plugs. starts first kick ides great responsive at idle. when you put into gear and go under load it has no power won't rev acts like you've hit a rev limiter. the headers are both an equal brown color so shouldn't be lean about 1 1/4 turns out. on fuel mixture. could it be the ignition breaking down. voltage at idle is 15 volts. this has got me stumped and it has new amal 932.

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15 volts at idle is way to much, how much volts you get at nomal revs above idle at most when your riding should only be putting out 14.5 volts max so I be checking out your electrics and if its over 14.5 volt you may be cooking your battery which will effect the running of your bike.

Ashley

Old gas?

Partially clogged fuel strainers in tank?

Slick

Have you re-torqued the head?

the he'd has been retorqued its good gas . i did go threw all the electrical because advance auto must of had a sell on butt connectors and the PO loved them. can you wire the coil backwards and it still run good down low? it has awesome throttle response but once you let out of the clutch and go to ride it runs like total crap. has great spark.

It could be any number of things,.. but I would try some tests and some observations to eliminate some causes.

take the air filter off. Use a mirror to see, or reach you finger into each carb body to feel for the needle going up and down with the inner carb body when you lift them when you twist the throttle. There's a circlip that holds the needle position that can pop off (as piero said)

Get the bike running on the center stand. Twist the throttle. When the engine starts to break up pump the fuel bleeder. Did it help or hurt the running condition? (a test for fuel starvation) clogged fuel line, screeen, sticky float, etc...

Get the bike running on the centerstand. twist the throttle. Spray some carb cleaner at the OUTSIDE of the intake manifolds while the engine is running. (test for an air intake leakage) did it effect the engine ??

remove the primary cover and inspect the rotor/stator gap. pull the plugs out and spin the engine over by having someone else turn the back wheel while in 3rd gear. How's the rotor stator gap? consistant as it spins?? any burnt marks on the stator from the rotor rubbing it??

IF you have a kill switch on your handlebar cluster, clean it. If you have an old ignition key switch, think about straigth up replacing it OR hot wire around the switch to see if the switch is so old and corroded that it's 'blinking" out on you from vibrating while you ride..

... there's more,.. but that should get you started...

Air leak!!!!

have you checked that you haven't inadvertently connected the Boyer trigger wires the wrong way round? They are NOT interchangeable, the bike will still start and run, but the timing will be way out and the advance curve all over the place.

dave M said:

have you checked that you haven't inadvertently connected the Boyer trigger wires the wrong way round? They are NOT interchangeable, the bike will still start and run, but the timing will be way out and the advance curve all over the place.

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That's a good one Dave.

I must say that my gut feel is that this one sounds electrical / spark / timing related too.

I had one with the cam one link off. Ran, but with no power. Very easy to mis count the links on assembly.

Also check that your air cleaner isn't saturated with oil. Happened to me once...