Trying to help a friend with a 2013 Zforce 600. It starts and runs but it won't go over 30 mph. I asked him if he has a seat belt limiter and he said he tried it with and without the seatbelt on which made no difference. My first thought was the TPS and I was wondering it there is a test procedure for it? Also is it a GM part like the newer ones? Anyone run in this yet?

[2015 Z Force 800 53/Trail EPS]

It won't have an ODB2 port. Just a 3-wire that uses their scan tool/PDA. If the MIL light isn't on, there are no system errors. RPM restrictions are on the overall RPMs, in 4wd with the diff-loc on and in reverse. If the pod shows its in 4wd loc or the gear selector switch went bad and shows the R light on while in a forward gear, it will also be restricted. Otherwise look to an engine problem, intake problem like a plugged prefilter bag or maybe some locking brakes. 

Everything checks out dash light wise. Today it hit 47 mph in high. I told him that maybe that's what a 600cc does  He's going to put a uni filter and a fuel filter on it and adjust the valves to see if anything changed. It's for trial rides so 47 is more than fast enough but it's new to him so he's unsure of what to expect with it. Overall it's a pretty cool machine.

[2015 Z Force 800 53/Trail EPS]

Everything checks out dash light wise. Today it hit 47 mph in high. I told him that maybe that's what a 600cc does  He's going to put a uni filter and a fuel filter on it and adjust the valves to see if anything changed. It's for trial rides so 47 is more than fast enough but it's new to him so he's unsure of what to expect with it. Overall it's a pretty cool machine.

It should do mid-50s...maybe a little more but if it has things like a full windshield that adds wind resistance that will take a lot off one with a the old 600. Bigger and heavier tires are a killer too..especially without clutch work.

It does have a full windshield and roof. Stock tires and clutching as far as we know. I'm betting that the belt is 10 years old and has 1,400 miles on it and that's slipping at full throttle. I recommend replacing the belt as a maintenance item as well.

An update on this machine. Fuel pressure was checked and it has 20 psi with the filter removed. He ordered a fuel pump and filter.