I did a little test run today, primarily wanting to put some miles on the new tyres…unexpected results in other areas tho.
A couple of months ago when I got the PCV fitted and bike tuned I also got them to put a 15t sprocket on the front since I’d kept bouncing off the gearing up until then and was looking for better cruising rpm (e.g. so I can cruise at 70ish over longer distances without revving like a twat the whole way). which is fine, but it meant I’d never had a direct comparison with before/after tune on the original gearing.
In the spirit of seeing just how good my “mud and snow” rated winter tyres are, I’m wanting to do some “local exploring” where I’d likely be wanting acceleration over top end so I put the 14t back on to test. Also for exploring a degree of stealth may be beneficial so I put the baffle in the end of the can (which I’ve also never tested properly). Without the baffle “stealthy” is definitely not a quality it has.
So having fitted the 14t and the baffle I take her out for a spin and seemed to be pulling really well – like she was really wanting to *go*…nice 🙂
It felt like the 14t (tuned) did make a difference. I hated the sound though, could barely hear what the bike was doing, no nice overrun burble/splot or end-of-rpm “knaaackpop”. It sounded a bit like a dodgy sewing machine. meh.
Thinking that if it’s going well now with baffle on then it should go better without – right? So I went home and pulled the baffle, and set off on my normal test run up to the next town…but weirdly it seemed slower. Disappoint. Also what the hell? Is it even possible that it’s quicker with the baffle in?
This isn’t the default baffle which comes with the exhaust (Danmoto carbon GP). It’s got that one in too (just before the can) as it was painfully loud without. This is a random aftermarket one I got in case it was still too loud for the track I go to. But the track folks never complained so I never bothered using the baffle.
I know 2-strokes need a specific restriction on the stinger for max hp, but is it possible that on a 4-stroke it actually benefits from that little restriction in the end?
I don’t know, but it *felt* quicker with the baffle. That’s obviously a very subjective assessment though so I guess I’ll need to do some sort of test to find out. I guess perhaps it’s possible that the baffle helps with low/mid-rpm pull, but then restricts somewhat at wide open throttle…or perhaps it’s fine over the whole rev range.
This wasn’t the result I was expecting.
Gearing-wise whilst it did feel quicker on the 14t I still think I may prefer how the 15t front rides. I’m not sure why that would be the case but since the PCV/tune it’s got midrange power where before there was really nothing happening below 8k, so perhaps the way I ride has changed. The 15t certainly seems nicer for just covering distances since you can cruise at 70ish with traffic.
For the time being I’ve put the baffle back in to see if I get more of that feeling like it wants to go, and will leave it on the 14t for a bit and see how it is on a couple of runs to work and back, but may well switch back to the 15t once I’ve figured out the baffle/no-baffle situation.
If (and its a big if) the baffle were to somehow help midrange pull then I’d be very interested to see how it is back on the 15t front, since it did struggle a bit to break above ~75 on the 15t with no baffle…like it can’t quite make it to the next power band unless it’s favourable conditions (e.g. downhill w tail wind), and then it’s fine. *If* the baffle does something magical to give it more midrange then it might mean it can bridge that power gap and perhaps the mythical 85 might be within range.
I will have to find a nice quiet stretch of private road and do a bit of testing with and without…and see what happens. Will post results…