I HAVE A PROBLEM SOMETIMES WHEN STARTING UP MY 1200 .
THIS IS LINK TO WHAT IT DOES WHEN I TRY TO START IT @ 2.30 MIN IN IS WHEN I ATTEMPT TO START IT .
http://www.youtube.com/watch?v=vMiiP...B3SyXqWMAQ0uW1

WHAT IS THE PROBLEM? THANKS IN ADVANCE

 

First, nice bobber, I’d like to do something like this someday myself. Second, taking a video is really a nice way to clearly show what the issue is instead of folks trying to second guess the OP. Third, please come back and tell us what the dyno tech said the issue is.

I’m no expert, but I can try and relate some of the things I’ve recently read, because I’m having the same issue and this issue seems rather common due to many many posts on this issue, but first I have to ask, before you started the bike in the video was the motor already up to operating temp? I ask, because this sounds like what is referred as a heat soaked kick back. Meaning the motor is already real hot, you turn it off to gas up for example, you go and start the bike after a short stop, and the bike just grinds, but starts on the second try. It sounds like there are many reasons for this kick back and this may not even be your issue. I’m sure someone will jump in and correct me, but hopefully my post will get this thread going.

Heat soaked kick back occurs when there is a hot gas mixture in one of the cylinders and the cylinder is at or near top dead center, the starter and/or battery is not strong enough to keep turning over the motor. Instead the motor kicks back against the starter causing the starter clutch to grind. Have you ever had a kick start bike? If yes, I’m sure you’ve experienced kick back at least once. Some of the reasons for kick back I’ve been reading about are: high compression motors that should have had compression releases installed (did you do a performance build on this bike?), weak battery, resistive connection from battery to starter, or just a bad starter clutch. There also seems to potentially be a relationship of kick back to a loose or shot compensator nut/spring, but I don’t know how a Sporty is setup, but it must have a compensator nut?

Some say a short term remedy, if the issue is compressed gas in the cylinder, is to bump the starter before you start the bike. I find rolling the bike forward in first gear enough to move the piston a little to be a more consistent short term fix.

Again, please post what your tech says is the issue and how he/you fixed it. I’m real curious to know.

 

What ignition system are you running? Some aftermarkey ones have settings for dead cranking where they do not fire the plugs until 3 revolutions.

It could be in this area that there is an issue...ie its firing too soon.