'72 hard to restart after running for a while.

[DougXS2]

like the title says, my 72 is REALLY hard to start if I stall it at a light or whatever after I've ridden for a bit.

I just recently put new pistons and rings on it, etc. and reset the valves, timing, etc.


any ideas what might be going on? (I didn't have this issue before the rebuild - also, I didn't mess with the carbs before or after the engine work.

 

[DogBunny]

When the engine is hot, you have to open the throttle (by twisting the grip), just a little bit. If a couple of kicks like that don't work, then it is probably flooded, and you need to open the throttle (by twisting the grip) all the way. If that doesn't work, then more details of your symptoms are needed.

 

[peanut]

bluddy ell Doug we are not magicians ! ....it could be literally anything ...electrical, ignition, fuel, air,valve settings , Timing, Advance .

We need a little more information to narrow it down .
What have you done to troubleshoot this issue for instance ?
What rpm does the engine idle at when hot ?
How does it run ?
does it surge when you cruise ?
does it pop on deacceleration?
Have you reset the Idle mixtures ?
Did you reset the carbs in sync ?
What colour are the plugs ?
is it stock ignition ?

 

[jussumguy]

Are your floats origional?
Do they have tiny cracks in them?

 

[DougXS2]

Turns out it was my points gaps.

I realized one of the screws that holds the points plate (one of them) had no washer. meaning it would change the gap every time I tightened it.

I added the washer and reset both points and now it starts better than it ever has. hot or cold.

I've noticed that it seems to have a slight pop or backfire sitting at idle. Only coming from the left side exhaust pipe though.

is that indicative of an air leak/lean condition?

 

[peanut]

Turns out it was my points gaps.

I realized one of the screws that holds the points plate (one of them) had no washer. meaning it would change the gap every time I tightened it.

I added the washer and reset both points and now it starts better than it ever has. hot or cold.

I've noticed that it seems to have a slight pop or backfire sitting at idle. Only coming from the left side exhaust pipe though.

is that indicative of an air leak/lean condition?

well spotted Doug nice easy fix .
Yes the popping is in all likelihood due to a lean idle mixture so either the mixture screw needs adjusting or the pilot jet needs changing or more likely a tiny air leak somewhere on the carb bodies or inlet rubbers.

Try spraying some carb cleaner around the carbs and inlet whilst its running on idle