Hey guys,

I commute highway miles mostly. I need max MPG's, not into racing or track (for now). But I was hoping to go +1 in the rear sprocket / stock front size. Will that give me a "tiny" bump in acceleration, without sacrificing MPG's? If I lose MPG's, by how much ??

I am not expecting big gains (acceleration) or much loss in gas MPG...

Your expert opinions are very much appreciated. I am new to this...

Thanks,
05 F4i.

 

i get around 38 mpg with a -1 front sprocket and stock rear.
i hear a +2 in rear is close to equal to that of -1 front.
so depending how many MPG you are already getting you can try to figure it out.
also i use it to commute through city and rural areas.

 

3 in the rear is about equal to 1 front.
You probably won't notice only +1 in the rear.

 

You won't notice the loss in mpg or the gain in acceleration. You really feel the bike is that slow stock?

 

If you're big on highway.. why would you ever go up in the rear? You'd actually probably be better going down. Besides the factory that motorcycle just aren't aerodynamic (actually it's the rider throwing it off).. they're not tuned for highway.. they're tuned for performance. But if you wanted good gas mileage you'd want to keep the rpm's low.. the tire pressure up, the AFR ratio lean etc.. etc..

 

^ ^ ^ That's what I thought 3 in the rear equal to 1 in front. SO... If I wanna keep it totally stock, but add a "little pep" or a tiny bit "pick up", would going 1+ in rear do that. As long as it doesn't slow down the bike from what it is Now (STOCK), and adds a Tiny Pep....Im okay with that. But not sure if I'm thinking right, or not.

Thanks!

 

My f2 has +1 on the rear with 15/44, it's not a huge difference but it's noticeable when pulling out of slow corners, and obviously no change in mpg with only a couple hundred rpm more on the highway. But next time I'll probably go +3 or -1 in the front.

 

I swap my sprockets around quite a bit.. (I have a collection). I was riding around w/ -1 on the front and got annoyed. I felt like I was shifting way way more for casual driving around. Now granted the whole 520 swap w/ aluminum rear probably makes you just slightly quicker because of the weight loss (biggest weight-loss is the chain). But would I go pick up a rear sprocket for anything less than $25.. nope. You could spend $150 on a PC3, get better mpg. and get way more pep. Of course I'm big on custom tunes because I think the default maps are substantially off.

 

Way more pep huh? Love them butt dyno's, they make you feel like you didn't waste your money every time. And I have a grip load of cash that says a PC3 isen't going to make me do better then the 50mpg I've gotten when I try. The only thing a PC3 does to even a mildy modified F4i is smooth out throttle response.

 

^ ^ ^ SO, it's doable !!! That's what I wanted to know. I don't want a HUGE difference. It's a 600cc Fi bike!! (my 1st bike ever, and I've owned it 3 months). So the F4i is "Plenty of bike" for (me). Has 25K miles, time to change chain/sprockets anyway. I don't expect, or even want big gains. (Good thing, it's not a CBR 250, as a 1st bike). So going up +1 in rear is just the "little pep" I'd want, without sacrificing MPG's (for daily commute). The stock chain is 108 links, but the one I'm getting comes with 120 links, so I'm sure the installing shop will cut it to fit the +1 rear sprocket. (is that okay?)

I intend to ride it more, learn on it more, and get as comfortable riding as I am with driving. I'll do that for at least a year or two, before I change the bike. What do you guys think... Am I off course as a newbie...?