426 high rpm sputter

I just recently developed a high rpm sputter on my 2001 426. bike sat for about a month (had a broke subframe bolt to fix) and when I fixed it and started it now has this sputter. I noticed when I was doing my subframe that my exhaust band clamp was loose and exhaust could just be pulled off by hand. So I tightened it all back up and while it has got rid of my popping on decel, it makes it to where when i open it up with the rpms up it misses and kinda sputters. Any ideas what this may be? maybe jetting is off now?

Hows the spark plug look?

good question ill look when I get home.

Old gas???

Main jet clogged, lacquered up from non-use.

so in other words imma have to tear into my carb no matter what pretty much. I am hoping its in the carb, i have lost alot of compression until it warms up. I assume my rings are not sealing well. So looks like there is a top end in the near future. Would that have anything to do with the miss?

... i have lost alot of compression until it warms up.
That is a symptom of tight intake valves.

would that cause the sputter, or is that more than likely just cause its an older bike and never had the valves adjusted before?

would that cause the sputter, or is that more than likely just cause its an older bike and never had the valves adjusted before?
Dirty carb, bad plug.

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