Hesitation At Wide Open Throttle

Fuel consumption seems low unless you are caning it in lower gears - even allowing for US gallons. Yeah they’re smaller!

The Gill electrics in these bikes are the single weak link. The most likely culprit for your problem is maybe not fuel but the pick up coil (crank position sensor OEM spare only) or the main ignition coil - replacement being PVL (sold as Nology in the States). Both have fine windings prone to breaks and going open circuit when hot.....intermittently when starting to die.

With 7200 miles the bike has obviously not had heavy use. Have you cleaned the carbs and the gauzes inline fuel filter adjacent to the T in the fuel line? It could be starvation or crud.

Next time it stutters check the tachometer. If it flickers you have electrical gremlins.

 

To add to Callumitys comments if electrical s are eliminated i would kill the engine where the hesitation comes in...preferably with some relatively new plugs...at that elevation it could just be starting to run a little lean when throttle is cranked open.

 

I think Tricky is referring to doing a plug chop as in checking the plug colo(u)r ..... although it appears he was distracted typing his post

 

LOL! just a bit what with the pain killers etc but yeah a plug chop at the hesitation point should give some indication if it the altitude that's causing the issue.

 

Good luck doing a plug chop with lead free and ethanol doped fuel.....

 

I think people learn to differentiate with different shades of carrot.

 

What like 50 shades of grey?

 

The Imperial system is pants as one of my friends would say

 

The Imperial system is fine.......or it was a system until it grew. I think the volume difference is down to leaky wooden barrels sailing from Liverpool to Baltimore and what was left when they arrived (that hadn’t been stolen in Liverpool docks!)
On the engineering side I recommend a slow walk through the Gettysburg Museum. The variations in weaponry and calibre are horrendous. The Confederacy bought anything they could get while the Union was relatively homogeneous. Great to see Whitworth guns!
We still struggle with our ballistic subs that are metric either end with Yankee Imperial stuff in the middle!

Anyway, modern fuel leaves a much less pronounced brown ring on plugs......kind of nothing or soot! Just like tails pipes no longer have the silvery dust of lead salts!

 

Of course there is....

 

Had a similar issue with my carburettor BSA ,turned out to be a badly blocked fuel filter, fuel would trickle through slowly, so ol at low throttle , but not enough at higher throttle openings.
Cleaned filter, washed out tank....sorted.

 

My thoughts are an aged bike that may have been sat some time with fuel evaporating in the tank, filter and carb bowls
Turn off the fuel tap, clean/replace fuel filter, drain the float bowls, put a concentrated amount of fuel additive in the tank, Sea Foam for example and let the fuel flow into the carburettors. Run the bike a bit until the fuel additive is in the bowls and let it sit there overnight to clean the system of any old fuel residue

This would hopefully clear the jets and any residue on the float needles/seats


Worth a go for a few bucks