| Author |
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Damnut
| | Posted on Friday, August 15, 2008 - 07:18 pm: | 
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I have a 35 mile commute to work with about 25 of it being highway. I would always use 5th going down the highway but have found myself not going out of 4th lately. I'm guessing my RPM's @80 are ~5-5.5K. Fun stuff!! I love beating on my bike though!!!
At least I don't have to worry about carbon buildup!!  |
Jlnance
| | Posted on Friday, August 15, 2008 - 07:30 pm: |
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I remember a discussion about this a while back, several people reported gettin better mileage at a slightly higher rpm on the highway.
I started one of those threads. Rode 80 miles of interstate in 5th gear, turned around and rode home in 4th gear. Got slightly better mileage in 4th. Others have tried. Some get better mileage in 4th and some in 5th.
It's worth doing this experiment yourself. The bike is a whole lot more fun to ride in 4th gear, and if your mileage is suffering because you're using 5th, it's a loose loose situation to be there.
(Message edited by jlnance on August 15, 2008) |
Froggy
| | Posted on Friday, August 15, 2008 - 07:59 pm: |
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I would love a 6th gear. I spend 90% of my riding in 5th. I tested the don't use 5th gear thing, and my gas mileage dropped about 10%. Even my computer was giving me lower numbers for MPG doing the highway in 4th vs 5th. |
Whitethunder
| | Posted on Saturday, August 16, 2008 - 12:46 pm: |
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I would love a 6th it would boost top speed and it seems like i am always fishing for another gear when i get to 5th |
Froggy
| | Posted on Saturday, August 16, 2008 - 12:52 pm: |
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It wouldn't boost top speed unless you got serious engine work done. The bikes are out of steam by 130mph. I have never made it to the rev limiter in 5th. |
Djkaplan
| | Posted on Saturday, August 16, 2008 - 02:38 pm: |
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You talking about your Uly? I could hit the 6800rpm limiter in 5th on my M2 when it was stock... I can hit it even faster now with the race kit. My bike's top speed is limited by the rev limiter, not by aerodynamic drag. A 6th gear may not make my bike faster with the stock final (or primary) drive ratios, but that certainly could be spec'd to provide a higher top speed in top gear. I bet I could bust 140mph if I had more gear.
You can't overlook the fact that acceleration would also be better because of less rpm drop between gears.
I want a 6-speed! |
Djkaplan
| | Posted on Saturday, August 16, 2008 - 02:39 pm: |
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And I'm getting one! |
Djkaplan
| | Posted on Saturday, August 16, 2008 - 02:39 pm: |
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... eventually. |
Froggy
| | Posted on Saturday, August 16, 2008 - 05:27 pm: |
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Both the Uly and my SS. Perhaps if i lost 20lbs, i might get another mph out of it. |
Paulxb12r
| | Posted on Tuesday, August 19, 2008 - 11:57 am: |
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At 130 the only problem with lack of power is that you have gone over the power curve I have hit 143 on my stock fire bolt and sure if a had a 6th gear with a .9 or .8 final gear the 12 could do 150 maybe even 160 but you would need a long LONG! Way to get up to those kinds of speed. I don’t think you could even come close to that on most of the tracks me run maybe Daytona |
Texas_firebolt
| | Posted on Tuesday, August 19, 2008 - 09:09 pm: |
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i tell you i want one just so i could drop the rpms a little and save some wear and tear on the engine. screw if it gives me better gas mileage or not. i dont like running my bike that high of rpm on the highway for extended periods. (i sure wish i woulda had one when i picked my bike up in atlanta, georgia. and rode it back 805.4 miles to ft worth, texas!!) |
Bombardier
| | Posted on Tuesday, August 19, 2008 - 09:11 pm: |
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Petebueller has manufactured a larger primary gear and has them for sale on this site. |
Texas_firebolt
| | Posted on Wednesday, August 20, 2008 - 09:08 pm: |
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the thing is i have a 9R and want the best of both worlds. i want all the low end but also the lower rpms at higher speeds. guess ill keep wishing... |
Petebueller
| | Posted on Thursday, August 21, 2008 - 10:55 am: |
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I geared my XB12 up with a custom primary pulley that has 4 extra teeth. 4th is now just a touch lower than 5th was.
The fuel consumption mixed city and expressway is about the same. I do enough expressway on the days I work out of town to be able to see if the fuel would be better. (I get 10% better since I fitted a Micron for example.) The bigger gearing has negligible improvement in consumption, maybe nothing.
Reports I've heard of the 6 speeds fitted to Sportsters have not noted better fuel. More comfortable and less lifting of the left boot are the main benefits.
A test bike with a Micron got to the rev limiter pretty easily with a custom 41 tooth when I was looking at sizes. My bike pulls the 42 tooth like it was what came with the bike. It doesn't feel like I've lost first.
If you can change the exhaust and tune an XB9 to get XB12 range power with perhaps a little less torque, I can't see why the bike wouldn't run well with an XB12 crank pulley. It depends on what you want out of the bike. I have one friend getting ready to put an XB12 crank pulley on his City-X and another about to fit an XB9 crank pulley on on an '07 Uly. Maybe they should swap bits.
The stock parts are cheap in the US, so it wouldn't cost a lot to try it and see if it is what you want.
Edit: I saw Bombadier's post after I put this up. Thanks for thinking of me.
The custom ones I have are for XB12s. You could do the same thing to an XB9 by changing to the stock XB12 pulley (and chain).
The custom pulley's I have as a kit with a chain, but they end up too pricey because of the chain. The chain costs nearly $150 to make, and the chain and pulley weigh over 3kg so they are expensive to post.
(Message edited by Petebueller on August 21, 2008) |
