Trying to identify a loss in top-end speed.
Hiya!
I've had my ruck for about 10 years now and I ride it every summer (2600 miles). It's a 2016 that I bought new and I've lightly modded it over the years. AFTER the mods, the ruck tended to run 40mph pretty easily and would hit 45mph on long flats.
I moved a couple of years ago (same general area/elevation), however, and now I tend to run at 35mph (~7800rpm) and top out at 40mph on the flats (~8600rpm). It's like I just left 5 mph behind at the old house...
For context, here's my potentially relevant mods:
- Airbox delete and Uni filter
- Polini variator
- Polini belt
- Dr Pulley Sliders
I do remember playing with the jets when I swapped intakes, but I don't recall what I ended up using. I can't recall the exact weight of the sliders, either. What's important to note, though, is that this is the configuration that was getting me 40-45mph.
Without changing any of those items, I'm now seeing the reduced top-end numbers. Since these items were working well for me, I'm hesitant to go adjusting weights or jets just yet. Dr Pulley claims the weights are good for over 12,000 miles, so I don't think they're worn out.
My guess was that the top ed reduction was the result of a maintenance-related issue, so I've done the following:
- Oil change
- Oil screen cleaned
- Fuel filter replacement
- spark plug replacement (looked light grey)
- cleaned carb
- fresh gas
- new battery
- inspected variator
- inspected sliders
- inspected belt (just over 17mm)
- checked tire pressure
At just over 17mm, I thought maybe this was due to the belt being a little worn, so I bought a brand new one (another Polini) but it was basically the same size.
I did a sharpie test (see picture) and I see that there's a little bit of the pulley that isn't being used, but the only pictures I can find of other test results are all "bad" and all show more than that, so I don't know if mine is normal or not.
Anyway, before I throw more money at this, does anyone have any ideas of what I might be missing here?
Thanks, ride safe!