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Discussion Starter · #1 ·
After reading through the forums I think this modification is unique to me! Can't see that anyone else has posted about it.

I ride my 2005 r6 mainly as a commuter bike, I drive about 100 miles a day round trip to work. Mostly on rural interstate at around 75-80 mph. So obviously my goal is improved gas mileage! So I shopped around, and found that AFAM makes a front sprocket with 17 teeth (1 more than stock). I ordered it and installed it. My logic was that it should drop rpm by about 7% and therefore improve gas mileage, and bring my speedometer closer to a true reading (my speedo was reading about 5% higher than actual speed, which is annoying).

After installing the sprocket I'm pleased with the ride, it did lower RPM about 6 to 7 percent, but I'm getting WORSE gas mileage than before. I was averaging 42-45 mpg before the mod and about 39-42 mpg after. So, the only thing I can figure is that I'm either riding the bike a few mph faster since the speedo is more accurate now (although I'm trying to account for that and ride the same speed) or else the bike physics just won't allow higher mpg, the power curve or something just isn't optimized with the lower power.

So I'm left with a decision, keep the 17T or go back to stock?? Gas mileage was my goal, and it didn't help. But I like the feel of the 17T and I like having a more accurate speedometer. Anyone else play with this mod to try and improve gas mileage??
 

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dont worry so much about mph, look at rpm as the rpm gauge wont be affected by the sprocket change. I would suspect the 17t should give you better mileage, and it is possible your going faster than you think due to the speedo reading lower than your actually going now.
Try 1 week with the 17t at whatever your highway rpm is .. then do the 16t week with the same rpm, NOT so much considering speed (but not so fast to get a ticket).
 

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Cuban Croc
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not to steal the thread, but this does have to deal w/sprockets. I noticed a person can buy +1 or -1 on the front and back sprockets or their any ideal combanations? Or should a person stick w/ 0,0. I am specifically talking about low and mid-range.

2. how does a person improve low/mid-range

3. how does removing the exup(sp?) and puting a full header/exhaust system effect the computer system.

Thank you for you time and comments.

Sorry runnerguy...just had thoughts and it seemed like a good place to post them.

I would also think an exhaust system and air filter would improve gas mileage.

-Al
 

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yea i was wonderin about changing the sprockets on my bike hopeing for better gas mileage on highway.. runnerguy keep me posted with your results .. on my 08 R6 when i am doing about 65 mph rpms at 6000.. so i was hopeing puting a biggere sproket would lower the rpm resltuning in better fuel milege.
 

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To the original poster;
The reason you are getting worse mileage is because with the larger sprocket in front, the engine has to work harder to move the bike. If you read the second or third post you will notice that to improve mileage, you need to up the power. What that does is lets the engine be more efficient, in turn giving you better mileage. And since our engines require rpm's to make the power, keeping it out of the power band will hurt your fuel economy. I would recommend you go back the the 16 tooth sprocket and mod for power. Put on an aftermarket muffler, airfilter and whatever else you want to give the bike more power at lower rpm's. you will not be twisting the throttle as hard trying to keep the same rev's which means less fuel going into the engine, which means better mileage. If you have any questions or want a better explination, pm me.
 

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Discussion Starter · #7 ·
rb4123, yes I believe you are correct, same basic conclusion that I came to.

Jaydeol, yes after several tanks of gas I'm still getting around 3-4 mpg LESS than before the modification.

I don't think I am going to switch back, however. The main reason is that when I commute, I like my speedometer to be ACCURATE. With the stock 16T sprocket up front, my speedo reads too high (as verified with a GPS receiver). For example speedo reads 75, actual speed is 70. With the 17T sprocket, my speedo reading is more accurate (again verified with GPS). This is because the speedo reads right off the countershaft.

If anyone knows how to adjust the speed (maybe a mod in the guage, or an actual calibration that can be done electronically?) let me know, I would go back to the 16T sprocket if I knew how to make the speedometer accurate some other way!

Thanks to everyone for posting!
 

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Discussion Starter · #8 ·
I forgot to mention, several have commented on muffler and air filter in relation to fuel mileage.

Yes I have a K&N Air Filter, and I also have a Yoshimura aftermarket exhaust (RC-3). No other mods except bodywork.

I'm getting on average 41mpg on my 2005 R6 with the 17T front sprocket, and most of that is on the highway at 80mph.

Pity me... there are NO twisty roads in Kansas, lol!
 

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Get a speedohealer and you can adjust the speedo to account for gearing, factory and tire size changes...check solomotoparts.com
 
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