the particulars…2010 rzr s with just under 2000 miles (about 161 hrs). generally ride around 7500-10000 feet. motor is stock except utv inc intake and d&d pipe. some added weight with an aftermarket cage, dual batteries, winch, light bars, but nothing too crazy. i am running a dobeck 4 and afr is 13.5 and 12.5-13 at wot
i never really paid much attention to the rpms until i went to a 14" wheel. thought it lost a little down low so i opted for a dalton kit. went with their recommended settings and the shift rpm was down around 5300 (versus the 6200 it should be up at). even pulling all the screws and going to a lighter tip rivet didnt really help. closest i got was 5600rpm. never saw the rev limiter, just didnt seem to get anywhere once it shifted out. ended up not caring for the tires so i went back to my 12" wheel/stock 26" tire. also set the dalton arms up as they suggested for high altitude and the 26" tire size (one size lighter on the rivet (2.4g), and running 2 long screws, and running the orange/blue spring). now my shift rpm is ~5300. at about 100-250rpm per gram, i dont see myself getting to the golden 6200 rpm shift rpm (and everyone’s experiences show that the dalton suggestions are pretty close to being spot on). i didnt go back to the stock weights because my rzr never got the high altitude weights like it was supposed to, so i figured it had been off since i bought it. for reference it came with 23-62s…the heaviest weights avaiable
it starts easily, idles well at 1140, run like a champ up until shifting out, and never hesitates top take anything i throw at it, but the loss of rpm at the top has me annoyed. rpms will continue to climb slowly once it shifts out, but i cant remember seeing 6000rpm. bought it new and from all the times i checked it has never been dusted. doesnt burn oil or ever run rough. air filter is clean
so i started thinking with it being so far off maybe i need to look elsewhere. so far:
1. new plugs…no change
2. new belt (no signs of wear on the old one)…no change
3. adjusted throttle pedal…was really close but took a bit of slack out…no change
4. verified full throttle was being reached…you can hear it click in the tb, so it is hitting the stops at open and close.
5. checked fuel pressure at the tank…i get right at 40 at key on and over a few minutes it will leak down to about 34 and that is where it stays. bump the key and it is right back up to 40. i dont have a connector for the quick disconnect so i havent run it to verify pressure while running. thought it may be fuel pump because of the weaker power up top and also my afr bounces around quite a bit some times.
6. havent had any electrical problems in the past. i have redone all of the grounds and added copper blocks so i dont think grounding is an issue
so where to go from here? compression test (even though it idles smooth and doesnt burn any oil…also no evidence of being dusted)? i dont have a tester so i will have to enlist help for that one (our local dealer sucks balls so i plan to avoid them). tps adjustment? any place i can get the tps tester for a reasonable price? any other quick checks i can try to narrow down the issue?
anyone else have similar results at altitude? am i just expecting too much at the altitude i ride at?
thanks for any help and i appreciate you taking the time to read this novel
