There has been some confusion as to the proper adjustment length for the exhaust valves on the Arctic Cat F7 and F6 engines (found in various Firecat, Sabercat and M-Series models). Originally, the 2003 F7 ownerâ€™s manual stated the proper cable length to be 36.1 to 38.1 mm. We published a cable length spec of 37.15mm in September of 2004 (per Starting Line Products).
Arctic Cat service documentation now indicates the proper and preferred cable length on laydown 700 & 600 engines to be 34.5mm. Weâ€™re told this spec is used on all F7s and F6s, new and old, stock and mod.
The important thing is that the cables are all equal in length (synchronized). As long as the cable lengths are equal and you are within this range, the ECU will index them and make sure they work properly. If the cable lengths are out of range, the servo will cycle 3 times and give up, leaving the valves in the closed position. The sled will run good on the bottom end, but not very good above 7000 RPM.
This measurement refers to the exposed cable free length, with the cables removed from the servo motor and all slack pulled back. The length spec is from the cable housing to the â€œbarrelâ€; only the steel cable portion is included in the measurement, not the cable attachment end.
Cable length adjustment can be performed using the adjuster nuts (after loosening the locking nut) that are located about half way between the servo motor and the valves themselves.
How often should this be checked? After time, the cables can stretch slightly which affects the synchronization of valve opening and proper valve timing. Starting Line Products suggests every 500 to 1000 miles, as valves that do not open fully are sacrificing top end horsepower.