need help with weird electrical problem

J

jimpapa

New member
almost finished restoring a 65' cb77 engine in a ca77 frame
well yesterday i finally got the last bolts put back in and tried starting for the first time.
unbelievably it fired up on the first kick. yeah:)
while i was adjusting the carbs i noticed no change on the left side made any difference.
i found out the left side wasnt firing at all.
looked at the points and realized i was missing a non conductive washer.
found missing washer and put in on and both cylinders started working

now

today i find the right side isnt firing???
point setup looks fine.
i pulled the right side plug wire while the bike was running and you can see it made no difference.
while i was putting the plug wire back on i can see and hear the right side starting to work.
but heres the weird thing. it only works when the wire in not on the plug but about 1/2 inch away from it.
i put a bolt into the plug wire end and then as i brought it close to the spark plug you could see the sparks arching across to the plug and you can here the right cylinder come to life.
but when you actually touch the plug with the bolt it stopped firing.

what the heck is going on?

tried pulling the plug out and connecting the wire and grounding the plug to the case and you can see the spark plug working.

i'm really confused.
 
jimpapa said:
tried pulling the plug out and connecting the wire and grounding the plug to the case and you can see the spark plug working.
Click to expand...
Swap the two plugs around and see if the problem persists on that side. Can you check the resistance of the coil and see if it's the same on both sides?

I had a brand new plug that was slightly internally shorted, holding the coil wire away from the tip also made it fire OK.

-Jamie M.
 
sounds like you need more voltage, maybe bad plug gap or plug.
coil fires at higher voltage to cross the large gap and then it has enough to pass the plug gap?
 
does this bike have 2 sets of points? my guess is timing is off on one cyl.. and the first spark delays the actual spark in the cyl.. adj one set of points till that cyl runs .. then do the same to the other cyl,, then back to the first .. till you find the sweet spot for both,,
 
thanks for the advise everyone. when i inspected the plug i can see a crack in it. so to be safe i ordered a kit that comes with new plugs , new wires and a new condenser.
when i get everything i'll let you know how it goes
cheers
 
jimpapa said:
thanks for the advise everyone. when i inspected the plug i can see a crack in it. so to be safe i ordered a kit that comes with new plugs , new wires and a new condenser.
when i get everything i'll let you know how it goes
cheers
Click to expand...

i am thinking its as simple as a bad plug? Or plug cap ? If you see that the spark fires when they are far apart then there is no reason why they dont spark after joining... unless when they are joined together something "weird" (sorry only word i could find to describe it) is going on

Keep us posted
 
Is it possible that you are using the coil from the CA77?
CB77s use 2 coils and the CA77 uses 1 coil with 2 coil wires.
The CB77 is a 180 degree crankshaft with 2 points and the CA77 is a 360
degree crank with 1 set of points.
Also the condensers are different.
 
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