Drive ratio change??? - Wrist Twisters
 
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post #1 of 14 Old 03-01-2009, 07:22 AM Thread Starter
 
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Drive ratio change???

Hey Guys, I have been reading that the stock drive ratio of 2.69 is not the optimum for the 919 instead it should be changed to 3.00 for faster out of the hole performance. Has anyone done this? Does anyone recommend it?

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post #2 of 14 Old 03-01-2009, 08:07 AM
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I never figured out the final drive ratio, but I too want more torque off the line. I was reading a bunch of posts about changing to 15/45 sprockets and it sounded like just what I wanted! Haven't bought them yet, but still want to. (Still looking for a good price). Have you read those posts about the 15/45 sprocket change? People say it makes the 919 so torquey off the line that you have to get used to it all over again! And that it tests your reflexes on how fast you can back off the throttle because it comes up so easy with those sprockets. Hey, I don't plan on leaving any traffic lights at 5,000 rpm so I doubt I would have much issue but the bike already wants to come up all the time in almost any rpm in 1st, I think it could get scarey for awhile. But hey, the 919 seems gutless from a dead stop through an intersection. Seems you gotta get the r's up to about 3 grand before you start to really take off.

So, I'm with you on the wanting more off the line! So I'm still seriously pondering the 15/45 sprocket set. Then THAT will be my LAST purchase/upgrade/mod (I promise, MarylandMike, I promise!).

Good luck. Let me know what you find out or decide.

post #3 of 14 Old 03-01-2009, 09:16 AM
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I have done that sprocket combo. BIG difference, like riding a whole different bike. Just be aware that it messes up your speedo by about 10%.

Spoiler:

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post #4 of 14 Old 03-01-2009, 10:51 AM
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Oh great! Just what I wanted to hear!

(kidding, man)

Seriously though, I forgot about that! It's like putting 4.56 gears in your rearend (not yours so-to-speak, but a car's) from having 2.79's or something. I remember when I went from 3.00 to 4.57's in my Ford 9-inch using 205/60-14's, my freakin' speedo said I was doing about 85 in school zones! (A slight exageration)

So, do they make different speedo gears/sensors for bikes? Or would I need to learn my lesson the hard way: by getting a ticket?

I sure get get all sweaty and worked up every time I think about that sprocket combo, but forgot all about the speedo reading changing.

Did it really make a huge difference off the line? Because I know I might lose a bit of my top end, but I haven't found a place yet that I've been able to really go fast anyway! My goal is quicker in the first few gears, especially from a dead stop. This 919 is NOT a bike you want to try to dart out in front of a car to squeeze into traffic like my GS-750 was.

post #5 of 14 Old 03-01-2009, 10:56 AM
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you can buy a speedohealer... bout a hundred bucks and you can set the speedo back to correct



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post #6 of 14 Old 03-01-2009, 11:01 AM
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holy $#@*! Add to that the price of the sprockets and I'll go broke.

post #7 of 14 Old 03-01-2009, 12:30 PM
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post #8 of 14 Old 03-01-2009, 03:43 PM
it's a honda, not a bmw
 
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15/45 is great fun around town.

Out on the highway or a longer trip it gets old quick.

Getting a 17t for the front is soooooo enjoyable on a 2hr+ ride.

I've also done 17/45 since it's only a 15 minute swap if needed.

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post #9 of 14 Old 03-01-2009, 04:57 PM
it's a honda, not a bmw
 
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Since hairball PMed me about it I thought I'd respond here to clarify.

I have also run 17/45 as an alternate for trips. 15/45 90% of the time around town for the fun and grunt, but I also grabbed a spare 17t to keep in the toolbox to swap on the front when a long road trip is expected.

Since the front is a pretty simple swap and doesn't require taking off the rear wheel it can be done in about 15 min or less.

Return from the trip, and pop that 15t back on there

17/45 is definitely not a real useful 'upgrade' just an option to save time rather than swapping out both sprockets back to stock for lower rpm highway cruising.

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post #10 of 14 Old 03-01-2009, 07:58 PM
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I enjoy my 15/45 setup; however it takes more control to handle the throttle and torque. Get comfortable with the throttle before changing gearing. Also the 15/45 isn't all that enjoyable on long open roads.

In addition to that the 15/45 is hard to control with a passenger. It is incredibly difficult to ride smoothly about 4k rpms with a passenger.

'04 919---40k----6/18/10 SOLD

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post #11 of 14 Old 03-01-2009, 08:17 PM
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Good idea I would have never thought of, having a spare front laying around. Heck, they're small enough that someone could take one along on a long ride then switch when you get to your temporary destination.

Next questions (since I'm full of them!):
Best brand?
Cheapest brand?

I used Sunstar several times in the past but they wore out faster than I wished they would have popping the clutch at 5 grand. I'd use them again since on this bike I don't do roll-on smoke shows like I did with the GS-750.

post #12 of 14 Old 03-01-2009, 09:20 PM
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i'm gonna put a 12/73 on mine...i wont be able to turn left anymore cause the sprocket will hit the ground.. but on the bright side i can wheelie in 6th......

(i'm just kidding...)



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post #13 of 14 Old 03-02-2009, 03:40 PM Thread Starter
 
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I like DeuceWI's idea of having the 17 for cruzin' but use 15/45 around town. I think I will do that too. Thanks for the input guys. Now all we need to know is what the best brands & where to find them at the best price.

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post #14 of 14 Old 03-03-2009, 08:19 AM
it's a honda, not a bmw
 
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I know for certain the 17/45 fits with the 'long chain'. It you removed a couple links for added adjustability I doubt it would fit, but don't hold me to that.

Just giving people a heads up in case they want to give that a try.

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