V1100 Sport misfire

Hello All. I have recently purchased a 1999 1100 Sport. At low revs the bike tends to misfire. It’s not a constant misfire, but occurs quite often at these low revs . Any ideas what to check?

Thanks

Just seen this:
Maybe too late.

Set the valves to Raceco settings.
In 0.2, out 0.25.
It sorts out low rev popping and farting and stops it conking out at traffic lights.