Larger Rear Sprocket, Pros/Cons?

[XFastStevwoX]

Hey everyone, I would like my next mod to be changing my rear sprocket to a bigger size (on an 05 600), and I was just wondering some things...

1. What size would be more practical? at VortexRacing, they go all of the way up to 53..
2. Ive heard this mod decreases your gas milage, but how bad? Does it make your gas mileage go down a lot or just a little?
3. Ive also heard that your top speed goes down quite a bit. How much does it go down?
4. About how many shop hours would a professional shop take to change just the rear sprocket?
5. Do I use the same chain and just have them add links to it or do I have to buy a new chain?

Thanks for the help guys....

[The CyberPoet]

Re: Larger Rear Sprocket, Pros/Cons?

Hey everyone, I would like my next mod to be changing my rear sprocket to a bigger size (on an 05 600), and I was just wondering some things...

Most of your questions will be answered here:
CyberPoet's Katana GSX600F GSX750F Sprocket Ratio and Sprocket Change webpage, at MotorcycleAnchor.com -- Now with oil temp gauges for Katana's!

1. What size would be more practical? at VortexRacing, they go all of the way up to 53..2. Ive heard this mod decreases your gas milage, but how bad? Does it make your gas mileage go down a lot or just a little?
3. Ive also heard that your top speed goes down quite a bit. How much does it go down?

See the above webpage for the answers to 1 thru 3.

4. About how many shop hours would a professional shop take to change just the rear sprocket?

Less than 1.

5. Do I use the same chain and just have them add links to it or do I have to buy a new chain?

Since you are going up in total required chain length to cover the total distance with a larger sprocket, you will need a chain with more links in it. Figure an extra link for each extra tooth involved.

Cheers
=-= The CyberPoet

[BeekMan]

Here's my two cents ...Canadian=1.59 cents US.

I've got a 49 tooth rear Vortex sprocket (my second aluminum) and left my front one at the stock size (15). I like this combination since I don't notice the gas mileage difference and I do get better pull. One summer when I still was stock and Spedee had a 50 rear and a 14 front, our fillups were consistently proving he needed 1 litre more gas than me...mainly because he was always about 1k rpm higher than me. That isn't enough to worry about for the added punch you get.
Yes, get a new chain at the same time. Do this just for the fact that your old chain will wear out the new sprocket much quicker. You do not need to change the amount of links (118) ie. you still need to cut off 2.
I have never noticed my top speed decreasing because I rarely try to go 240km/hr so don't worry about it.
You can change the sprocket yourself in less than an hour so don't let the shop charge you for more than that.
Good luck!

[KnightRider]

WOW. A litre for each tooth added in the rear.....4 teeth would equal a gallon "perse" hmm.

[SweetLou]

Not a liter per tooth, a litter per fill up.

[BeekMan]

A litre extra per fill up based on +3 teeth in the rear and -1 tooth in the front....compared to the stock setup.

[KnightRider]

Oooh, totally worth it then. Thats still a good days ride on a fill up....Im doing it!

[XFastStevwoX]

Ill still whoop you Eric... I dont think im going to do it, all of the chains ive found are all like over a hundred bucks..

[DooD]

I've gone to 13T(-2) in the front with a 49(+1) in the back so I could stay with steel.....I didn't really want to go to aluminum.

The bike pulls WAY harder than it did before..the front end almost leaves the ground if you chop the throttle, but not quite. Any more change and it would probably come up a bit - but for now I think it's better that it stays planted.

The bike runs a lot slower now, and it's impossible to tell how fast I'm going. I usually set my throttlemeister to keep 'er going at about 140Km/h on the highway, at which point I'm normally doing about the same or sometimes a little faster than traffic, which usually moves at about 120. So yeah...BIG difference there! Usual highway speeds bring about RPM's in the 6000+ range now......so it's definitely a little noiser too.

As for speed....at redline in 6th she'll still register about 239...but my actual speed is closer to about 215. It's quite a big loss of top end, but who needs to go that fast anyways?

The other downside is that I could usually pull off about 325-350Km to a tank with stock gearing...now I'm doing about 280. Of course, that's riding it HARD on the highways, with lots of high-rpm city riding as well. I had a couple close calls last season with people who didn't know I was beside them, so now I tend to ride a gear below where I used to. I've found that the noise brings about more shoulder checks from cagers......which is always a good thing.

I think a good place to start is a -1 front....That's what my first step was, and I found that it did give the bike a decent increase in acceleration, without ruining fuel economy. It also allowed me to make a fairly good performance mod without going bankrupt. When I did my sprocket switch, the chain and rear sprocket were showing very little wear, and the mechanics all agreed that I would just be able to swap the front sprocket out and not replace anything else. I think it cost me about $50 in total. As I went through another season, got my knee down, and generally felt more comfortable aboard the bike, I found that it was still a little slow off the line, so I made the second change to it's current setup - which is great for city riding and ripping local twisties.....but really sucks on the highway. It just feels like you're torturing the poor thing when you run it at 6500 for an hour or so.

[trinc]

a 15-50 gearing will need a 120 link chain. it's better to go up in the rear - less wear on the chain.

top speed ? yes you'll lose some, but it's better to have it pull harder than outright top speed ( which the kat needs a loooong runway to get there anyway )

tim

[rotary13b]

By looking at Cybers chart (great job done) with 15-50 set up u will only lose around 15 to 16 km/h of your top speed, depending on the size of your motor 600/750. I'm planing to change my rear sprocket on my 750 as well, justn can't decide wether I want 49 or 50?

[simple guy]

Hi,
When I had my 2000 750 Kat I went +3 at the back and could tell a small difference at the seat. I used a 120 link chain and removed 2 links.

Many other people that went -1 front and +3 in the rear had a noticeable acceleration change. my2cents

jim

[dark169]

I droped 1 tooth in the front when I changed my chain this spring, made a differance but nothing major. Its got some go but I wouldnt go out of my way to do the change. 1 or 2 in the rear wont do much either, but it may be worth a try and worse case you switch back after the season.

[rotary13b]

Well -1 in the front = +3 in the back. True?

[md86]

Yup . I did the -1 in front last spring . Biggest thing I noticed is that 1st gear goes REALLY fast compared to how it was .