from the gearing standpoint. I don't know that changing things around would necessarily be the best for the '07s. The gearing, to me, is a mix of performance and economy. The whole point of the 6th gear is for 'cruising'. On the flats... you can engage it at 60mph although I typically don't use it till a minimum of 65. 60mph=2krpm in 6th where 70mph = 2,400-2,500rpms in 6th gear. 6th isn't made for 'performance' really. You want performance so when you twist the wick it will respond .... then I'd recommend you downshift to 5th or not even engage 6th at all. Havin a good time and cruisin around where you are riding solo or with friends you will probably not use 6th and let 5th handle things up to 80 or higher.

Also I don't know I'd really want to run my bike at 1500rpms (even if it doesn't "SOUND like it is lugging). Bikes are basically designed for 2k and up in the RPM range. 1500 to me says you aren't pushing out the exhaust as well as you should. Even with the earlier bikes' mods for this gearing and running at 1500RPMs I would imagine the heat starts to build up more as you aren't pushing out enough through the exhaust. I would 'imagine' a little more 'bluing' of the pipes going on as the heat builds up.

 

I have a 95" and stock gearing, whatever that is. It is an 02 RKC. Anybody know what gearing came on that bike? And if no big bore guys respond to this thread then there must not be any running gears and BB. I volunteer my bike. Donations please.
Gary

 

you have the 3.15 in the '02. I believe some said '01 was the last year of the 3.37.

Also, as I stated above, BrianTTM and PhilM both have well over 100 HP bikes and are running 98/95 inches, and have the 3.37 and they love them. So maybe they didn't see this thread, but they have 'em!

 

Why would you build up more heat if your bike if tuned?

Again, as I stated above, it sounds counter productive to run 1500 RPM's but the bike has NO problems with lugging and chugging. I had to stay above 2000 RPM when cruising with stock gearing, now I can go much lower and the bike doesn't struggle. It's a mechanical mathmatics that allow the motor to work easier. The bikes were ORGINALLY designed to turn over 2K RPM with the ORIGINAL gearing.

If you don't understand the theory, then see if you can ride an '01 or someone's bike that was changed to 3.37. Otherwise, I can't help ya!

 

My bike is a high compression 95" Underground Performance heads/Woods cammed motor that puts out well over 100/100 TQ/HP & I LOVE the 3.37 gearing.

~John

 

Unless I'm misunderstanding what you're saying (very possible), I call shenanigans on this one. You're saying you went from burning 3/4 of a tank to 1/2 tank. That's a 1.5x increase in gas mileage. To put that in perspective, that's like going from 30mpg to 45mpg.

 

I know is sounds hard to believe,But I'm rounding here. My needle was showing just under 1/2 tank, my wife's bike was on 1/4 tank, maybe a hair over. End result was that the mileage increased. I guess I would have to do an official test to get the true numbers. So, I wish I had the data to back it up, but I don't. Rest assure your milage wouldn't decrease.

 

You guys think your getting better gas mileage with lower gearing? well I guess we should all run out and put 4.11's in our street cars like they did in the 70's for hole shot. Quit using your gas gage as a miles to the gallon calculator and go get some real numbers by filling up and setting your tripometer at 0 then run a 100 miles and fill it back up and devide the 100 by how many gallons you put in for a true reading. I took my gearing the other way and got rid of the 337 plus added a 6 speed to get rid of the high rpm's in all the gears now my bike is a 2.94 final drive. I have a 99 with the front wheel odometer so I just change to a 34/65 pulley comboon the tranny/rear tire with a Revtech 6 speed too. I cruise 80 mph at 2750 rpm and 75 at 2500. The rule of thumb is if you keep it below 3000 rpm you are going to see better gas mileage. I have not calculated my miles per gallon yet because I need to have my PCIII dynoed. But if lower gearing is giving better gas mileage when I am done I will go back to the 3.37 and forget about the math that I put to my gearing.

 

I have something similar on mine. Because the Baker DD6 uses a different compensator sprocket, the ratio is slightly different ~ something like 3.32, I think.

I like it. However, w/o my 6 speed, I would not do it. But.... that's just me.

 

My bike with the high compression 95" motor running Underground Performance Heads, Woods TW-6HG cams, Wiseco 10.5 forged pistons, ST 2-1 pipes& a Woods Rebel 43.5 carb got 47 mpg on the road the last time I bothered to check. I don't know what it would get with 3.15 gearing & I don't really care because I usually beat the hell out of it, but if it is adversely affecting the mpg it sure can't be by enough to worry about......

~John