Hitchcocks Forum

Hi, I have recently fitted a Hitchcocks Stage 1 kit to my 2005 Electra X, the power increase is great but I am suffering a lot of backfiring on a closed throttle using engine breaking which was not happening before the upgrade. If I add just a tiny amount of throttle back in then the back firirng ceases.

With the clutch in and the revs dropping there is no bickfiring.

The new downpipe was a very snug fit so I don't think there is any air entering at the head.

Can anyone advise a solution or has anyone else experienced this?

Thanks

Appologies, title should read Electra

By backfiring do you mean spitting back through the carb or popping and banging in the exhaust on overrun? As it seems to be the latter I would have another go at sealing the pipe in the exhaust port and the silencer. Ordinary silicone RTV paste does a good job.



Is the carb that came with your kit one of the newer type Amal Premier Mk1 versions with the aluminium alloy body and anodized slide? If so, you will be able to try a slightly larger pilot jet. If it's one of the more common zinc body type with the fixed pilot jet you're stuck with what's in there unless you fancy some fiddly work. I'm guessing you have the pilot air screw adjusted properly.




A.

Hi, try following the Amal tuning tips (Amal section of this site) when setting the air screw. A slightly lean mixture will cause an exhaust pop when closing the throttle (slow corner gear change etc). Try a 1/8 turn in on the air screw. The pilot jet size is probably ok as supplied by Mr H and as Adrian says it can only be changed on the premier MK 1 version. Good luck

My ElecraX with the same upgrade does this a bit and I'm convinced it's exhaust-pipe related. Presumably it only happens when hot like mine? There's a thick steel reinforcing ring inside the entry point to the down pipe that I bored out and made bigger which seemed to help, but I still get it occasionally. I'd try the silicone trick first though as it's quick and easy!

Stephen

If it is popping on the overrun and nothing to violent and you find the solution can you let me know. I inadvertently tuned mine out, not sure how, but would dearly like to get it back. A joyous sound.

Popping on the over-run is as far as I am aware a characteristic of many large single cylinder "British" motorcycles and part of the "charm" and nostalgia.

Hi all, sorry it's taken so long to reply to all the great advice, I have been working and only just around to looking at the the bike again today. I removed the entire exhaust and refitted using some high temp gasket paste. I could see that the exhaust gases had been escaping as the header end wasn't sitting exactly flush. I still get a few backfires on the overrun but nothing like the violent and very load ones I had had before. Thanks again for those who commented. I'm sure I'll be back with more daft questions as my relationship with this bike develops.

Hi there, you may wish to try some sealant between the pipe and silencer as well. To echo Bob, use the tuning notes to set up the air screw.