600 rpm loss

[Blackzed]

\having some troubles with my 06 600 keeping rpms. starts out good but under load it will losse 1000 rpm ? this sled has 62 g wieghts 2" 144 track with 20/41 gears it usely runs strong

 

[ElectroTech]

Primary spring would be a good place to start, exhaust valve cleaning second.

 

[hecks]

Not sure if the 06's had a fuel filter or not, but you may want to have a look.