XJ650J Tuning/Performance issue

I have a 82' XJ650J MAXIM and love it..... Fantastic bike. The bike was sitting in my garage for about 12 years. After rebuilding, cleaning, adjusting float level and bench syncing and installing the bikes started right up. Bullet proof.

I recently installed aftermarket pipes (MAC) and noticed some lean performance issues. I've changed the main jets from #110 to #112 and this made a big difference. My problem is now adjusting the air-fuel for a slight performance issue.

Under all of my test conditions the bike accelerates beautifully, all the way up to red line. This was not the case previously before the jet change. The bike would hesitate intermittently from start to redline and then resume.

I've currently adjusted the air-fuel screws to 1 1/2 turns, but am noticing a conistant little bit of popping on deceleration. I'm not an expert and am not sure if this would be a lean or rich condition. At 2 turns the bike seemed to have less popping and would only slightly occur after acceleration and then letting off of the throttle slightly.

Anybody have any thoughts?

 

go another 1/4 turn out and see where that gets you and report back with results

 

Welcome - Popping is usually lean. Best way to set your mix is read your plugs. Search on plug chops and you will find a ton of info

 

Thanks 86xj700_indy and Bill.

I'll go out another 1/4 turn and give it another try. I'm pretty close and this may be the closest I get until sync the carbs with a manometer.

I'll also pull and read the plugs as Bill suggested although with all of the fooling around I done over time to get it right I may have fouled a plug. Maybe installing new plugs at this point, now that I'm so close, would be best.

Thanks again. I'll let you know how I make out.

 

and in case you were wondering - I have a YICS tool for the sync process or as Bill puts it a hole in the head