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So looking forward to the big thaw...soon I hope as it's gonna dip into the negatives again tonite around here. Thinking of my pre-ride chores and one thing that I recall from last year was after sitting out at work all day in cool weather I was getting a real nice backfire, about like a shotgun, when starting. I actually think it's pretty cool but it usually causes unsuspecting pedestrians to dive for cover and/or soil themselves. Prolly not a bad idea to see if I can tone it down a tad. Now I run 150 mains, 45 pilots, Uni-pods and Epcos, and when I'm starting cold outside like this I'll pull the choke out about 1/2 way. Any suggestions on getting this under control?

Less choke and don't twist the throttle while cranking. Backfires can be destructive to machinery.

What ryk said. don't even touch the throttle on start.

yup had that same issue, no throttle prime, 1/2 choke fire it up and pull joke if required after she fires up.

Yeah, don't touch the throttle, and usually at 1/2 choke. Seems the bang happens mainly when it's cool enough out to take a bit longer than usual to kick over. Funny though, when I cranked up for the first time this year, no back fire. All of about 40 degrees out too. Interesting...

Hmmm...happens with new gas or old...perhaps a I might be looking at lightening up the jetting a bit?

Maybe with those big jets of yours you need an enleanerner in lieu of an enrichener?

Thanks Doug, for posting this. I usually get a good bang when cranking her and always assumed it was normal. When I fired her up today, I tried the 1/2 choke and it was much nicer.

Thanks !!

Steve

When cold, I hit the starter with no choke and let it spin a turn or two then pull the choke. No issues although my ride rarely backfired anyway.

I think if tuned right they don't tend to backfire, I know mine never does. Not sure what difference the Procom might make since I know they tend not to start as easily.

Yeah, I'm hardly a true wrench guy, so how do I know if things are tuned right? Followed the online jet calculator according to pipes, intake, needles and elevation and came up with a slightly higher size for the main jets than I'm actually using. What else can I toy with as far as tuning goes?

Jetting is most important on our bikes but you should also make sure the pick up coil gap is right. The jetting calculator is not accurate in many cases but close enough for a good starting point.