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Sprocket Kits

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datguywhowanders

New Member
Joined
Apr 28, 2009
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9
Location
Iowa
www.siouxcityrollerdames.com
Alright, so I was browsing through the ebay listings today, and I came across this:

520 Conversion Sprocket and Chain Kit

I've done a little reading about them, and I think I sort of understand how making changes one way or the other can either increase acceleration or top speed. From what I read, it sounds like one usually means a loss of the other.

This auction is quoted as saying this though:

"Stage I - Ideal for most sport riding enthusiasts- This is generally meant for someone wanting a lot more acceleration and for easier wheelies etc. This combo will generally let you pull wheelies in one gear higher than you can with stock. This is also a good starting combination for roadracing and track days (except for very long tracks). With this setup the goal is to get the maximum performance out of a bike without sacrificing any top speed. This is generally how I think most bikes should come geared from the factory for optimum performance. "

Is it possible to do this to improve performance in response and acceleration w/o losing top speed? If anyone is more knowledgeable about this and could break it down for me, I'd really appreciate it.
 
I have no experience with it but I do know that you can only do one or the other. Otherwise if you don't want to lose both then you'll have to keep it stock.

My theory is the more teeth is has the faster the sprocket rotates and grabs the chain faster? The less then it grabs it less... <--- not a proven theory, just a guess.

I heard a member here likes the faster acceleration but lost the top speed and could only go 126 mph. Not like you'll ever go that fast on the streets for a long time any who.
 
I just read that a -1 rear sproket is a good mod...helps top speed and lowers crusing RPM...also read that +1 front sproket is possible if you do some grinding...I hope people that have done gearing changes chime in...i'm interested too. -2 or -3 rears as well...
 
What you're messing with is the rear ratio. By increasing the rear sprocket, the front driven sprocket has to spin more times to get the rear sprocket to go around once. Picture it this way. If both sprockets were 50 tooth, for every revolution the front one spins, the back would spin the same. That's a 1:1 ratio. But if that rear sprocket were 100 teeth and the front 50, the front would have to spin twice to get the rear to spin once. That's a 2:1 ratio. (You divide the larger rear sprocket by the smaller front to find how many times the front has to spin to get the rear to spin once.) The higher the ratio number, the slower your top speed will be because the rear can't spin as many times at the max RPM of the engine. It's the same way your transmission works. So if ours is a 14 front and 46 rear (I think that's what we have stock) our ratio is 3.286:1. By going -1 in the rear, that changes to 3.21:1. For every revolution of the rear sprocket, the front has to turn 3.21 times. That's less than if you're running the stock gears. So it'll give you a higher top speed at the same RPM or a lower RPM at the same speed. But it'll also take away acceleration. If you were to do what a lot of people have done and go with a -1/+2 (13 front/48 rear) your ratio is now 3.69:1. So for every rotation of the rear sprocket, the front has to rotate 3.69 times. This will give more acceleration at low speed because the engine can spool up faster without having to get the rear spinning as fast. You use this so when you're coming out of the corners, the engine can spool up and get you up to speed much faster, but your final top speed will be slower. Most of the time that doesn't matter because we're rarely if ever pushing the bike to it's max speed. But we're usually slowing down for a tight corner and then accelerating hard out of it. This gives worse gas mileage because the motor will be be at a higher RPM range to cover the same ground.

Hope that didn't confuse people even more. :o
 
If you decide you want better top end and gear it as such, you would have to watch and stay closer to the power band exiting turns to get that drive. There is a technique of using engine braking and trail braking to keep revs up throughout the turn to get the best acceleration coming out. Other than drag racing this bike pulls good from low rpms, just not the HP as other bikes. $.02
 
Something else (aside from how the gearing can be altered), the FZ6R and XJ6 run a 520 chain as standard so there is no need to convert (the idea of running a smaller chain is to reduce inertia in the drive chain and reduce unsprung weight-as these bikes are not ridiculously powerful they can run 520 and get good chain life).

The upshot is, if you want to alter the gearing and the chain is in good condition, why not just buy the different-sized sprockets that you desire?
 
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I'm not tracking this bike so acceleration out of "slow corners" isnt something I'm concerned about to be honest...I'm pretty happy with the acceleration as it is and since I've only used full throttle a few times and just blazed through the rev range in a couple seconds or so I'm in the camp of riders that would prob benefit with a slightly taller ratio. I dont like the idea of grinding anything to change the front sproket but the rear I think I'll change out when I get the time to play with it. Right now I'm too busy riding like crazy!!! I'm just wondering if I'd even notice -1 rear...maybe -2 or -3 would make more sense...

I can ride all day at 65km/hr in 6th...and thats according to the manual that states shift point to top gear is after 60km/hr...thats geared pretty low I think...I couldnt imagine what -1 F +2 R would be like? Idling out of first and 50km/hr top gear:eek:
 
stuna said:
-2 on the rear for me , i get 47-53 mpg . looking at -3:D
Click to expand...

Seems like that would put a lot of stress/wear on the clutch... how is your first gear take offs? Lots of clutch feathering to get it to go, or not much of a diff? Seems like it would bog bad in first with anything more than a -1.
 
+1 front wont fit without grinding off the metal tab or so I've read...

So -2 in the rear wasnt too much and youre thinking -3 now...hows the acceleration with -2???

I blazed up to 150KM/HR today from a slow 2nd gear to 6th shifting over 10,000 under full throttle and I'm quite impressed at how hard this 600 pulls. My buddy in his 996 was impressed too as he was barely catching me up...Like I said I bet I couldnt even tell -1 rear.

oh yeah and what does the speedo do when you went -2 rear? I think I'm in the same camp as everyone else that has +8% error with the stock gearing.
 
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speedo still reads high. +1 in the front , i would have to mod the eng case . i did not want to do that:confused:. -2 only changes it by a few percent , so take off with two on it is no biggy
 
Superfly said:
+1 front wont fit without grinding off the metal tab or so I've read...

So -2 in the rear wasnt too much and youre thinking -3 now...hows the acceleration with -2???

I blazed up to 150KM/HR today from a slow 2nd gear to 6th shifting over 10,000 under full throttle and I'm quite impressed at how hard this 600 pulls. My buddy in his 996 was impressed too as he was barely catching me up...Like I said I bet I couldnt even tell -1 rear.

oh yeah and what does the speedo do when you went -2 rear? I think I'm in the same camp as everyone else that has +8% error with the stock gearing.
Click to expand...

where did you read about +1 at the front grinding the 'tab' off? im intrigued. Guess i might have to pull my sprocket cover and see what harm might be done.

Would definitely help to improve speedo accuracy, its almost as optimistic as Gordon Brown!
 
joloy133 said:
Stock: 16 /46 = .348 , a +1 front : 17 / 46 = .370 , a +1 -2: 17 / 44 = .380.

Do you want top end or wheelies?
Click to expand...

-2 rear = 16/44 = 0.364
-3 rear = 16/43 = 0.372

+1 front = 17/46 = 0.370 (gives a near perfect speedo apparantly)

So if this theory of +1 front fixes the overclocked speedo then -2 rear will make it close on the overside and -3 rear close on the underside...prob within a mile/hr.

BTW is it a fact that all our speedos are pretty much off by 8%???
 
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