Hello all,

I recently installed a dynojet kit and a hmf pipe with the quiet core on my 2004 vinson. I followed dynohets recommendations it runs much stronger now but it seems to backfire quite a bit. And is very cold natured now. Hopefully someone can give me some info, it would be greatly appreciated.

 

I also put the hmf pipe [with or without quiet core], dynojet kit, and k&n filter on mine. It was backfiring on decelleration at first, but after adjusting the mixture screw it straightened it out. Dynijet kit reccomends 3 turns out for my area, but 2 1/2 was better. By the way the dynojet # was 126. The vinson is already a strong machine, but these simple mods made it a lot funner to ride.

 

I am in ohio and they recommended the 124 for 3000 ft and below, with the screw out 3 turns, mine backfires some on deceleration but also when you rev it alot and let off, so Im not sure. Yes it truely does make a big difference. Also I'm still running the stock filter but I have a twin air on order.

 

The backfire on decell is a symptom of a lean idle circuit.
You could have a loose connection on the carb intake, or exhaust leak. If that looks ok, then you could go one size bigger on the pilot jet, and redo the mixture screw setting.
That would help both the cold motor drivibilty and the back fire

 

I talked to tech support at dynojet today and they said that I dont need to change the jet. he told me to make sure my mixture screw was out 3 turns and If so turn it out another half turn at a time and that should fix it. But I think that would lean it out but I could be wrong I'll just have to try and see.

 

Hes right about turning it out, thats richer. But theres a limit to how much that can be turned out...and 4 turns is about the max, then a bigger pilot is the fix.

 

yes he was right, i'm going to try it in the next day or so, I will mark it and go a quarter turn at a time and yes 4 turns is the max. Thank you for your info man!