super sport breaking up

[mikeyboy1]

my 76 750  F runs great for 5 miles then starts sputtering like she's running out of gas.have just relined the tank w/POR.thought this would solve it.carbs have been cleaned,new plugs.starting to think something electric is breaking down when hot.any ideas  ?
thanx  Mike

[TOOLS1]

My first thought is that that crapy tank liner is breaking down, and plugging up the petcock/fuel filter, or the vent in the cap is clogged/plugged with that crapy tank liner.
TOOLS

[Re-run]

No no, it is kreme that is garbage. Unless a person botches por 15, it is a very excellent tank liner. If it is coming off, it wasn't given time to cure or the tank was not cleaned and etched properly.

More likely it is something else. The vent cap could very well be plugged with dirt and old fuel. The petcock filter could be plugged too as it happens to any filter.

Mikey, get a fuel can and long line to drain your fuel. Connect the line to your petcock and open it up and see how it runs. If it flows good without trickling, then we can look elsewhere.

[mikeyboy1]

the POR is new-it's not peeling.petcock is clean & flowing freely. vent is a possibility-where is it? is the cap vented? hadnt thought of that. points are new & set rite.she runs great for 5 mi. then starts choking. I dont think the cap is vented but the tank has to be.no ?

[Re-run]

Yes, the vent is in the cap. Just a small hole really.

[TOOLS1]

Any tank liner is CRAP in my opinion.
TOOLS

[Re-run]

Some genuinely suck, some are very good unless the proper procedure is not followed. It's no different than paint. Preparation is a very big deal and will make or break a tank job.

[shinyribs]

I think Rerun is on the right track. Take it out for a ride and make it produce the problem. Immediately open the fuel cap and see if you can her a whoosh or hiss of air entering the tank. If so, that will tell you it had ,in fact, pulled a vacuum and the and vent needs attention. Good luck!

[mikeyboy1]

well the vent is working fine.I swapped the coils from my K,which work fine,
. still have the same problem so it's not coils ,wires or caps.re-cleaning the carbs tonite.havent seen any red flags .will try her again tomarrow but dont have hi expectations

[Re-run]

When you pull the carbs, make sure you remove all the jets manually and look through each one to be sure they are clean. Turn in your air screws and count the # of turns, then take them out and make sure those areas are clean. Make sure it is all spotless inside.

[mikeyboy1]

well,here's the story.the gas cap vent was plugged.and the points & timing were off.then it wouldnt idle down because#3 jet needle was a bit out of adjustment.now all is well in super sport land & she's going up for sale.thanx everyone.
Mike