Bonneville America Forums Forums Technical Forums Performance Mods Back fire on decel-Epco Stainless-Air box removed

Back fire on Decel.

If I rejet the carburators, will this problem go away. Do you have advice on the type and size of jets to use.

I had a Dealer that was not so great, install the freak airbox removal, install the K&N's and install the Epco stainless pipes. I'm not sure if they re-jetted.

I am starting to do my own maintenance and was wondering if I need to re-jet.

Any suggestions.

Deborah

I'm running Epco pipes and I'm currently at 130 main/45 pilot jets and 2.75 turns on the idle mixture screws with little to no popping. I'm still running the stock airbox but I'll be removing it soon and installing the Freak kit with the K&N filters. At that point I'll be going up to 150 main jets.

Hi Deborah and welcome aboard!

Minimum, you have to check what your main jet size is right now and while you have the bowls off, you can find out what size pilots you have also!

I have a similar setup and have the stock 42 pilots with 150 mains. Air screws are out about 3.25 turns. Depending on where you live altitude-wise, this may or may not be be a good starting point.

Start with air-mix screws to see if it helps. Turn them all the way in first, and then back them out to 3 turns, or maybe even 3 and a half. If that doesn't help, you might want to go with 45 pilot jets if you have 42s in there now. Pat's site has all the info you need to do either job.

Thanks for your advice.

Deborah

Just about to sort my own popping on decel problem. Hate to sound like a total dunce but where are the air/mix screws exactly ? I can't find 'em for lookin. I've got Keihin CVKs on an America.

T.

Dinqua.com

Cool thanks. Didn't know they were covered by a plug !

T.

It depends Tony. What year is yours?