Honda CBR 600RR 520 conversion

[Vtec44]

Here's my attempt to explain what is a 520 conversion...

The number 520 mainly refers to the the size of the chain, or the size the width of a chain. The first digit (5) designates the pitch in 1/8' incriments, while the second digit is the multiplier. So a 520 chain has a 1/4' width (1/8 * 2) while the 530 chain has 3/8' width (1/8 * 3). I'm not sure what's the 3rd digit is for, someone please add to this thread.

Stock 600RR's come with 525, which is a bigger & heavier chain. The 520 chain is lighter, which will also wear out quicker. But, a lighter chain reduces rotational mass, which in turn gives you better acceleration. Most people also change the gearing, or sprocket size, at the same time when they go with a lighter chain and sprockets. Same concept applies to the sprockets, reducing rotational and unsprung weight. Althought, the change in gearing has a more noticeable effect than reducing rotational and unsprung weight alone.

I recently did the conversion on my bike, with a gearing change of -1 tooth on the front sprocket and +3 teeth on the rear sprocket. I haven't taken my bike out yet so I can't tell you how different it is compare to stock.

Feel free to correct me or add more to this thread.

[Asian Dave]

Does the 520 kit really make a difference? When will I need to replace my stock set up? I'm at 8K miles.

[Vtec44]

My stock F4i went 18k miles on the OEM chain, lots of track days and commute. It's hard to give an exact number of miles to when you need to replace your chain. The manual states that you replace it when the chain stretches out close to the red area on the alignment marks on your swingarm. But with a lighter chain, around 10k is a good starting point. I think rotational and unsprung weight reduction alone won't feel much of a difference compare to the gearing change.

[Asian Dave]

Hmm...

Any preference on chain or sprocket brands?

[Vtec44]

AFAM sprockets and DID chain on my bike, AFAM sprockets (-1/+2) and DID 520ERV3 Gold. Check with http://www.nomadicmoto.com to see if they have a kit for your bike.

[Jotaro]

I'd go with whatever for the front sprocket (since it's steel [chromoly] anyway),
and supersprox if I have the money with RK XSO chain

[AdvSac]

Significant link for this thread is: http://www.dropbears.com/u/utilities/index.htm

It has the sprocket coversion chart for seeing what final drive you looking at with different sprocket combo's. Mind you, the smaller the front sprocket the more you wear the chain because it has to twist more. So there is a limit. And you can see that moving one tooth in the front is the rough equivalent of 3 teets in da back!

[bredebee]

My bf did a 520 conversion on his Kawi ...he said it made a very noticeable difference . When I can afford to I am going to put one on the Track Slut

[Czolgosz]

-1 +3, went from 525 to 520. Huge difference in acceleration.

My zx is mostly run on the track (slowly but surely will be track only) and the 520 w/ -1 +3 was a great addition for most of the tracks I run on (except maybe big willow).

I'd likely stick w/ stock gearing for running street (to/from work and weekend twisties) for the gas mileage and wear.

I had 12.5k on my stock components and they look like they could easily do another 5-10k before having to replace them.

[Dr. GoFast]

damn, i guess i'm in the minority. i have 13K miles and my chain is in the red replacement zone :rolleyes i ride mostly street (GMR/Azusa), but also track. i will go with 520 with stock gearing.

[NomadRip]

Going -1 / +2 makes about a 10% difference in the gearing as far as things like speedo reading. It accelerates quicker, but at the same cruise speed, the motor is revving higher and the speedo reads more wrong than it usually does. -1 / +3 makes the variation even bigger, but it sure is easier to wheelie and it gets up and goes much quicker.

On the 600rr's the wear factor of a 520 kit doesn't seem to be much different than the stock, from what we've seen.

[papasmurf]

I recently did the conversion on my bike, with a gearing change of -1 tooth on the front sprocket and +3 teeth on the rear sprocket. I haven't taken my bike out yet so I can't tell you how different it is compare to stock.

Feel free to correct me or add more to this thread.
I will tell you right off the bat, be careful going on it full throttle off the line or in 2nd, your front will come up quick fast and in a hurry! I did a -1 in the front with stock in the back and it was a huge diff, so -1 +3 is crazy!

just be careful common on 600rr is -1/+2

stock front is 16t -1 becomes a 15t
stock rear is 41t +2 is 43t and +3 is 44t some guys will go -1 +4 on short tracks like streets of willow... 15/45 its a good combo!

[Vtec44]

I will tell you right off the bat, be careful going on it full throttle off the line or in 2nd, your front will come up quick fast and in a hurry! I did a -1 in the front with stock in the back and it was a huge diff, so -1 +3 is crazy!

I had -1 on the front prior to this change. Yeah, it came up a few times at Buttonwillow but but nothing unmanageable. By the time I get back on this bike, it will be about 1 year since the last time I've ridden so I'll be one hell of a slow dude. Thanks for the warning! :D

[papasmurf]

yeah it will be way different...so just be careful for your sake! Might scare you the first couple times you go full on the throttle! I know it would scare me a bit! it will pull like crazy!

[LanceB]

I did -1/+2 on my bike. Daddy likey.

[Built B16A]

i just looked at that website, and i have a 16/46 stock. and -1 down and +3 is close to stock..

but can anyone explain why this helps the acceleration? if your final ratio is the same.. how can it help pick up and go speed?

i understand the 520-525 size difference now.. so i take it you can't mix match gears either. for instance. i have a 525 OEM chain. i could prolly use a 520 sprocket on that 525 chain but would'nt recomend it right?

[Vtec44]

Nope cuz theoretically it won't fit right and will wear out the sprockets quick.

It helps with acceleration because you're idling at a higher rev range. For example, cruizing at 80mph will be at 10k rpm instead of 7k before. So, you're within the power range of a typical 600cc sportbike. When you twist the throttle, you're closer to torque peak, therefor, accelerate much quicker because you need less time to rev the bike up. On top of that, ligher procket and chains of a 520 size reduces rotating mass and unsprung weight. So you're closer to torque peak and can also get there faster, that's the idea behind a 520 conversion & gearing change.

[The Sauce]

Nope cuz theoretically it won't fit right and will wear out the sprockets quick.

It helps with acceleration because you're idling at a higher rev range. For example, cruizing at 80mph will be at 10k rpm instead of 7k before. So, you're within the power range of a typical 600cc sportbike. When you twist the throttle, you're closer to torque peak, therefor, accelerate much quicker because you need less time to rev the bike up. On top of that, ligher procket and chains of a 520 size reduces rotating mass and unsprung weight. So you're closer to torque peak and can also get there faster, that's the idea behind a 520 conversion & gearing change.


This helps, but what really makes the bike feel 'peppier' is the gear reduction that you're doing. By making the engine sprocket smaller and the wheel sprocket larger, you're giving the engine more of a mechanical advantage.

[Vtec44]

Yeah, the gear reduction is the culprit of causing your bike to cruise at a higher RPM.

[Built B16A]

ok.. so im still trying to understand this.

lets say for conversation sakes... -1 in the front, and +3 in the back = a stock F4i setup. thats what the chart relates from the conversion on dropbears.com..

OEM.. 16/46. = 2.88 FD.
.........15/43 = 2.87 FD. close enough..

even though the teeth are geared differently, at the end of the day, your still hitting the same top speed. i understand the whole unsprung weight, thats common with automobile autocrossing, wheels, and flywheels.. but how can the gears alone make the bike feel faster? we're not changing transmission gears...

doesn't the larger, more spread apart gear in the front compensate the more close together teeth in the rear? i just don't get it.

from common sense.. if you went down a tooth in the front, and left the rear alone, i would imagine you would gain a bunch of tourqe but loose top speed. if you went more teeth in the rear, same stock front.. you top end would be unbelivable but take off liek a dog. so if you change gears to equal out in the end, doens't it just cancel out?

[NomadRip]

ok.. so im still trying to understand this.

lets say for conversation sakes... -1 in the front, and +3 in the back = a stock F4i setup. thats what the chart relates from the conversion on dropbears.com..

OEM.. 16/46. = 2.88 FD.
.........15/43 = 2.87 FD. close enough..

even though the teeth are geared differently, at the end of the day, your still hitting the same top speed. i understand the whole unsprung weight, thats common with automobile autocrossing, wheels, and flywheels.. but how can the gears alone make the bike feel faster? we're not changing transmission gears...

doesn't the larger, more spread apart gear in the front compensate the more close together teeth in the rear? i just don't get it.

from common sense.. if you went down a tooth in the front, and left the rear alone, i would imagine you would gain a bunch of tourqe but loose top speed. if you went more teeth in the rear, same stock front.. you top end would be unbelivable but take off liek a dog. so if you change gears to equal out in the end, doens't it just cancel out?

Bigger rear is the same effect as smaller front.

Here, use this gearing calculator (http://www.gearingcommander.com/) to figure it out. It's probably more complicated than you care about, but it might help you understand it.

[Built B16A]

http://www.tamparacing.com/photopost/data/500/RPM_final_drive.jpg
http://www.tamparacing.com/photopost/data/500/current_speed.jpg
http://www.tamparacing.com/photopost/data/500/custom_speed.jpg

the RPM's are HUNDRETHES apart. the FD is almost exact. how does gearing adjustments make the bike feel faster?

now, i could understand sprocket adjustments to achive one thing, but you can't have best of both worlds. front sprocket... less teeth, more acceleration-less top end. more teeth, slower bottom end, better top end... vise vera for the rear...

so unless you need higher top end, or better acceleration, you have to give one one end of the performance some how. matching the gears close to stock (-1, +3) won't do shit. right?

[Vtec44]

the RPM's are HUNDRETHES apart. the FD is almost exact. how does gearing adjustments make the bike feel faster?

I plugged in 80mph with 15/45 (-1/+2) and the RPM is about 1200 difference in 2nd gear, and 1100 diffference in 3rd gear. Those are the 2 that you'd use the most on a race track, especially setting up for corners.


now, i could understand sprocket adjustments to achive one thing, but you can't have best of both worlds. front sprocket... less teeth, more acceleration-less top end. more teeth, slower bottom end, better top end... vise vera for the rear...

-1 on the front is about -3 on the rear. So the setup of -1/+2 can be done by just getting a +5 rear sprocket.

[Vtec44]

I finally got a chance to test out my 520 and -1/+2! Wow, the bike seems to be in the "sweet" spot in any gear. Although, I got a bit confused on how many times to down shift based on the speed I'm traveling. On top of that, the bike now have the tendancy to power wheelie easier. Something that I kind of expected but not this easy, given that I don't even know how to hold a wheelie. Also, I'm curious to see how quickly the bike will run out of speed at California Speedway.