front sprocket part number question

[Val]

Yeah it's all food for thought and down to personal preference

What's the difference in front and rear sprocket numbers? I see some kits have 15 & 48, just wondering if it's worth going for different sizes and what it'd do?

Good question play with this and see the difference: http://www.gearingcommander.com/

Some people do 1-2 tooth more on front and 1-2 tooth less rear. That basically will make the RPMs lower. The gear commander will give you the difference and few nice graphs.

Here is  my understanding how the secondary transmission ratio and acceleration works.

If I increase my secondary transmission ratio say from stock 15/48 I go for 13/53 sprockets, the bike will have more acceleration and pulling force. Not torque. Torque always stays the same for same RPMs not affected by ratio. Obviously you can't change the engine HP either. But you can change the way you transmit the torque to the wheel.

Say with the stock 15/48 in second gear doing the same RPM say 4600 I will have 10 fts2(foot per second squared) acceleration going with 31 mph and the pulling force will be 210 lbf.

With the custom 13/53 in second gear doing the same RPM say 4600 I will have 14 fts2(foot per second squared) acceleration going with 25 mph and the pulling force will be 270 lbf.

Most people do the opposite which means less acceleration more speed with lower RPMs. Means the highway ride will be more relaxed and according to some guys Fazer has some vibration around exactly 70mph with standard transmission. Making say 17/47 will make RPMs lower on 70mph and will make the vibration disappear. But IMO the slow town ride will be not so comfty.

There is one more important thing - ratio also affects chain wear. Look at gear commander wear table. Standard ratio 15/48 means front sprocket will do 3 turns before the same chain link hits again same tooth, rear 24 turns before same tooth hits same link or [size=0.7em]Both F&R  each 24 turns[/size]. If you do 17/47 that changes to 17 and 47 turns and for [size=0.7em]Both F&R ecah 799 turns!

This will make the wear less with some custom settings.
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Here is standard ratio speed gear shift chart:



You calculate ratio by dividing the sprocket tooths, so standard is 48/15=3.2, top speed 143mph on 11500 RPM.

If you do higher ratio say 53/13=4.08 here is the graph you basically get more aggresive ride with a lot of acceleration but shorter gear and the max speed on 6th will be lower on the graph it says top speed 112mph. That is what motogymkhana guys do. They get massive acceleration with massive rear sprockets, probably massive fun too  :lol



And here is more reasonable for relaxed highway ride lower ratio for 17/47=2.76, you have longer gears and higher top speed on 6th 165mph on 11500. I doubt you can do that speed, nevertheless the gears are longer with higher speeds, see on 1st you can do 62mph on 11500. More people will short shift means you do not wait to use full gear capablities till 115000 RPMs you shift earlier.



Here is performance analyser for accelerations, pulling force and speeds depending on your final drive transmission ratio:

http://motorcycleperformanceanalyzer.com...azer-1998/

More problems what to choose I guess LOL

All the thanks go to J_Dub for providing the link to Wemoto site where they have all JT sprockets range with custom tooths count too :-)

[url=http://"http://motorcycleperformanceanalyzer.com/yamaha/fzs-600-fazer-1998/"]
I'd get one of these; http://www.wemoto.com/bikes/yamaha/fzs_6...ront_-_jt/ and don't forget to buy a tab washer too!
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[url=http://"http://motorcycleperformanceanalyzer.com/yamaha/fzs-600-fazer-1998/"]

I may go with 1 tooth less on the rear for now. Which is miniscule change for ratio, but about 7 times better wear.

Forget about the initial parts number question, I am completely undecided now what sprockets I should choose now  :lol [/url]