Motorcycle Repair: 1998 honda shadow vt1100 bucking/stall, honda shadow spirit, mechanix gloves

Question
hello, i just bought a 98 honda shadow spirit vt1100.the only thing that was added to the bike from previous owner was vance&hines slip-ons and carb was jetted for them.i was entering the highway and during a hard throttle up in 2nd gear the bike bucked and stalled.did the same thing again in 3rd.seems on hard throttle in high gear it happens.light throttle through the gears it's ok.if you goose it a little in gear it sputters and bucks but doesn't stall.idling and revving it up it doesn't sputter or hesitate.i don't think it's a fuel problem because it cuts out fast without hesitation.i'm thinking ignition/spark related?any ideas? thank you,walt

Answer
It sounds like a jetting issue, With slip-ons you shouldn't have to do any significant jetting...have you pulled the plugs and looked at the color of the burn on them ? If it is dark and sooty then you have a rich condition, if it is very light, almost white then you are lean. This needs to be done when you have just done the acceleration and experienced the issue, try to hold the condition for a few seconds and then find a place to shut down asap, now is when you need to remove the plugs and check how they are burning. Check both, they will be hot-wear mechanix gloves !
Are the original jets available ? What type of jet kit did they install ? Did they drill the floats ? I hope not ! Some jet kits recommend this and it is a bad and expensive idea !

 if you are accelerating as you mention up in 3rd or 4th gear try applying the choke, this will enrichen the mixture and if it seems to clear out and accelerate more smoothly then you are too lean. The opposite applies, if when accelerating as you mentioned you slightly back the throttle off and the bike accelerates or seems to clear out a bit the it is a leanness in the jetting.
I am betting the bike is too rich...
Thanks and good luck !