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Old October 10th, 2010, 08:55 AM   #1
JMcDonald
ninjette.org sage
 
Name: J
Location: Oklahoma
Join Date: Sep 2010

Motorcycle(s): 2008 250R

Posts: 771
Ordered 16/41 sprockets :O

I had been looking into sprockets for a while, just because so many people seem to say how much it improves the ride. But, I wasn't sure how much I wanted to do. However, after a while I realized I really like the longer length of higher gears, vs the initial snap of shorter gears. I get much more excited about pulling in (factory) 4th from 40-70 to get around some traffic, vs a run from through 1st and 2nd (it always feels disappointing to shift into 3rd and look around to see I'm barely pulling away from traffic, heh).

Most of the time I find myself shifting into 2nd from stops as soon as I am going fast enough to bypass the neutral finder, if I don't just leave it in 2nd altogether. It might take a little but more clutch work (not that it took a whole lot, even in 2nd) to get a good start on the rare occasion I need to quickly get ahead of traffic from a light or something, but I think it will be well worth it. Though, I never launch and have no real desire to bother, so I am not worried about any loses in performance from like 0-10mph. Besides, if I need to accelerate so quickly out of the hole that 1st is too long, I probably don't have enough room to safely do whatever I was trying to do anyways :P .

I will probably install the sprockets in a few days or perhaps next weekend and report back. I also ordered a dynojet kit and will be ordering a pod filter (K&N R-0990) and probably building a full exhaust. However, those won't be going on for a few weeks (all in the same weekend, along with painting ), so for the moment I will be all stock except removed snorkel and shimmed needles (which I think I over-shimmed, heh). All of those will hopefully help get some more peppiness back.

The combo is a bit over 25% faster for a given RPM. Speeds at 12500rpm, according to www.gearingcommander.com, will be increased by the following amounts (rounded to nearest whole, in mph)

1st: 35 to 44
2nd: 51 to 64
3rd: 64 to 81
4th: 78 to 98

From what I've read on here, True Top Speed (TTS) would be reached in 5th, say around 105mph (up from around 95 (104 indicated) being the fastest I've gone, with about 92 true being the typical TTS), at about 11500rpm. 110mph would be around 12100. 100mph would be about 12750 in 4th.

6th gear will be largely used for just cruising down the highways. 5th gear could be used as a half-way point between factory-6th and geared-6th, like for going up a steep incline or facing a good headwind. It will get very slightly over 10mph per 1000rpm (theoretical 102mph at 10k). So, it will be nice cruising at 7400 for 75mph, rather than the current 9200rpm, as it will hopefully reduce some vibrations going through the foot pegs (both front and rear pegs).

Where I would normally cruise in 6th at 45mph (5500) I will only need to get to 4th (5700rpm) for about the same cruising RPM.

I am excited that if I need to quickly pull out into traffic, I can be doing 40mph at about 11500 in 1st (and almost 46 by redline), vs doing barely over 30 at that RPM. In general, since I daily ride my bike and have to take a lot of short trips, I like knowing I can get going a little faster in each gear without having to rev up a cold engine. That way if, for example, I am trying to keep the RPMs below maybe 5000 for the first couple of stoplights, I will only have to go up to 4th rather than 6th to be at 40mph.

With this gearing combo the distance between sprockets only goes up by .38" . My chain adjustment is pretty far forward as is, so I shouldn't have any issues with running out of adjustment room.

When I do the install, I will post pics and might even try to make it a DIY to complement the current sprocket-swap sticky. If nothing else, I will definitely include pics and details on how to grind the sprocket cover (or how not to do it, if I destroy mine--or how to make a new one, if I destroy mine :P ).

My biggest concern is the odometer. If I am not mistaken, it will read 25% slower, if it doesn't get its reading from the front wheel. But, it would be technically off no matter what I did with the sprockets, so I will just have to keep track of this.
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