Hitchcocks Forum

Did a chop, what do you think, main jet up a notch? That’s my thoughts.

Looks a little hot and bothered for an enfield. How does it run otherwise?
Was that a chop from full throttle?

Looks like a nice clean burn to me, if it is running well with no pinking, I would be tempted to leave it alone.

Pretty well. Yes, that was fourth gear at full throttle.
Pulls slightly better in third, than fourth, but that’s speed related. I only get the same pull in fourth if I’m at least 45 to 50 mph.
If I’m below that speed in fourth and snap the throttle there is bogging. Interesting, as the Amal hints and tips say if engine is heavy at full throttle, it’s rich! Not by my plug it’s not!

Ah, just seen your post Paul. I was tempted to leave it, just don’t want to end up holing a piston.

'Plug chops' are a subject where there is a lot of misplaced expertise. A full throttle chop is only of any use on a racing engine – tuned to run at full throttle.

For a road bike what gives a reliable guide to carburetion and plug grade is an average reading taken after a lengthy run at normal running speeds. That will indicate the reading that means something.

I’ve been asked about plug readings for engines that have been run only stationary and idling. Asked why it was so sooty!

The plug in the photo on this thread is too bleached - but does not tell anyone very much without the plug being read after an average run of a few miles - and without knowing the plug grade used and how fast the bike was run for how long. As I guess this engine is not run normally at full throttle (!) it would mean more if the plug was read after an average ride.

Bring on the Colourtune

Bet Bill Lacey never used Colourtune!!

The plug I’m pretty sure is a standard B7HS.
No not run at full throttle constantly, like many bikes, generally ridden somewhere around quarter throttle.
This chop was at full throttle in fourth only after about three mile run, though I had come to a stop and then ran a few hundred yards before the chop.
I had done a Colortune a few months back, but of course that’s for idle mixture.

Hi John - do you know what jetting you have in the carb?
And what is you normal average road speed and approx distance of an average ride?