Hitchcocks Forum

One for all the experts on here. My Electra X engine has started to pop on the over run, reduced throttle as I approach junctions, etc. I thought this was un-used fuel igniting in the hot exhaust as sign of richness. But looking on line I get all sort of answers. Weak mixture, air leak in the exhaust....? So as it is an Enfield and I know you lot are very helpful so I put the question to the forum experts.

nature of the beast, or something not as air tight as it should be in the exhaust system.

Very commonly this is an air leak at the exhaust pipe/cylinder head.
The best sealant for this is just plain ordinary silicon sealer (bathroom sealer)
Make sure everything is clean first and smear sealer on both surfaces. Push together and wipe off excess.

Oh, hang on; Electra X; you have a sealing ring on that joint, not just push fit like the Bullet.
Same applies though, very possibly an air leak there.

What Pete says
Mine does it regularly, don't bother me as it keeps the mong in motors at a safe distance. Can sound like an Uzzi if I change down early

PeteF,



that's absolutely fine, seal it properly with the silicone RTV and it won't need a sealing ring, my Electra-x and AVL Hybrid have run happily without



A..

Thank you all. Just checked, the idiot who rebuilt the engine after a top end strip didn't tighten the exhaust clamp bolts properly - me!

Just as an add on to this topic, one cause of the popping is the wrong adjustment of the decompresser. I have found that when adjusting the decompresser cable you need to make sure the exhaust valve is not being kept open. One method is to unhook the cable from the small lever coming out of the push-rod cover and run the engine, by moving the lever you discover the neutral position between to points you feel resistance.

Digging this topic up again, I noticed today that when I pushed the choke back to 'normal running' I got banging in the exhaust on reducing the revs - on over run. Pulling out the choke a short way 'cured' the banging. Any thoughts?

A low tick-over is also a cause of banging in the exhaust.