Sprocket Splendor

I just completed my final project on the Vffrer for this year. I've had the parts for about a month , but since my stock stuff was in good condition,
whats the hurry. Anyway I bought new sprockets and one of those DID x-ring
chains. The only change that I made was to go +3 on the rear sprocket. I
kinda figured this mod would do little to improve performance, especially since the V-4 is a very torquey engine. Well anyway, all my scientific postulating was way wrong. The +3 larger rear sprocket really helped. I no longer need to play with the clutch just to get moving. Besides that it seems to have improved the pulling power /acceleration in all the gears. And I rarely live up in the 150MPH zones,to say that it hurts top speeds, Anyway for a couple hundred bucks its a nice modification. eddie

 

Eddie, where does one pick up a sprocket? and are there any repercussion's to such a mod?

 

I went +2 on the rear with my bike and I am pleased with the results. The only real draw back is that you lose top end speed, but like eddie, I am never in the 150 mph range.

 

What about fuel consumption is there a big difference???Same speed,higher revs!?

 

Hey Jason and Dan-Slo; As with anything, there is always a flip side. Depending on how much you increase the number of sprocket teeth, your engine will have to rev a little higher,I believe with mine its about 5%. I havent checked fuel mileage,but I cant see that it will be all that much.
Plus with the bike geared lower it wont put as much of a load on the engine.I
bought my chain and sprockets at Indy superbikes. My sprockets are made by Vortex, quality seems to be very good. Eddie

 

I'm getting 42 MPG. I've never run my '07 with the stock gearing, so I can't speak to what I would be getting with the stock gearing.

 

nice simple cheap mod eh??

I have geared down both my 00 and my 05, It made more of a improvement in the 05, really helped with its low speed drivability. much nicer around town and going slow. .
My mileage is very close to before on hiway near legal speeds, falls off a bit faster I go, maybe couple mpg.. but worse rest of time cause I drive crap outa it every time I gear them down.. My 05 would run even with my 00 when i geared it down, so it did help a few lengths on pickup. Either way, maybe not earth shattering diff, but the response feeling is always noticeable!

Top speed is a hair better on both bikes as it will pull more in top gear now. I can run a bit closer to the kids gsxr at top end now..closer, not even..

sure made it more fun punching it in 1st gear as they always do that nice easy wheely now. I just gear it back up for my long trips, leave it down for shorter stuff as its a simple change that I enjoy. As for the speedo I dont use it much anyway,I just go by the tach once I get the rpm figured out.

Enjoy!!

 

That is the main reason I geared down my '07 as soon as I got it. I was coming off a '99 and had read that Honda had widened the gear ratios on the 6th Gen. I had stock gearing on my '99 and even then I thought that it was too tall, so for the '07, I knew I would not be happy with the stock gearing.

 

nitro
I don't mean to pick but, if you increase number of teeth on rear sprocket it is mechanically impossible to increase top speed. Maybe you drove faster because of increased confidence.
I did enjoy the pics though. it looked like a beautiful trip through the canyons. I am jealous of you guys in the PNW.

 

Well MY bike would never pull top rpm in 6th gear..geared down it will, in the end it goes faster..works the same on most cars i have owned also..kinda same deal as runnin your economy car in drive vs overdrive..Now if you can pull top rpm with the higher gear then of course you cant go as fast..In my case on the level ground I can pull more rpm, enough to be going faster than with the stock setup...downhill its a diff matter...

 

Believe it or not it is possible to get a higher speed with lower gearing. With lower gearing you will have more available torque which will help to reach top RPM. This will only help if the bike with stock gearing can not reach top RPM in 6th due to lack of power.

The perfect example is my old '85 Honda Shadow 700. In "overdrive" the bike would do about 105 but if I would keep it in 5th it would run about 118 by the speedometer.

 

an interesting discussion

let's say for sake of argument
that you have an engine whose top rpms are 10000 revs
front sprocket has 10 teeth
rear sprocket has 40 teeth
it requires 4 rev of front to turn rear once
resulting rear sprocket or wheel rpm is 2500
change rear sprocket to 50 teeth
this resulting rear sprocket or wheel rpm is 2000
given the same size tire speed has to be lower.
your decrease in speed is where the increase in torque comes from.
I stand by my statement.
I don't know anything about the 85 shadow so i cant address that

 

What you are saying is correct as long as you have the horsepower to get to the 10,000 RPM in your senario. What I and others are saying is that if the engine can not produce enough power to get to 10,000 RPM in the highest gear, you can lower the gear ratio slightly which will allow the engine to produce more torque (due to the lower gear ratio) and possibly reach a higher speed because the engine now has the ability to reach the 10,000 RPM mark.

Let me try to explain this a different way. If you have a bicycle with different gears, try putting the bike in the highest gear that you have and pedal up a very steep hill. More than likely it can't be done. Now by lowering the gear ratio you are able to pedal up the same hill faster. This is the point that I am trying to make. The only way that lowering the gear ratio can increase speed is if there is not enough horse power to get the engine to top speed in the highest gear.

 

on my bike I hit a computer shut down between 156-160. I was watching the road not the speedo when I hit the limiter. The last number I saw was 155 then I started down hill and hit a limiter of some kind) My first question is this normal? I still had like 2000 rmps till red line... I ran out of power at 155 I was only able to hit the shut down because I started going down hill. It makes complete sense to me that if I had lower gearing I wouldn't have run out of HP and with the extra 2000 rpms I could have topped out sooner at the same speed. How do I fix the speedo if I change my gearing? I've wanted to do this for a while but I can't decide if I want +3 or +4 teeth on the back sprocket. I really like doing wheelies but I don't need to be doing them in 3rd gear... I've done a couple small wheelies in second before on accident with the stock gears. I'm not a very big guys 150lbs how much difference will this make in my gear selection?

 

enlightenment

I get it now.
Horsepower is a function of engine torque
not the other way around as i previously thought
this is why I love this site. multiple heads are better than one.
at least the one i have

 

FWIW, when I did this same modification to my '98 VFR, I wore out the Vortex aluminum rear sprocket in fewer than 3,000 miles.

jD

 

Hey J davis; Yes I am running a new Vortex aluminum rear sprocket; I really dont have very much experience with that Manuf. but if my sprocket goes south that fast I will be returning it back to Vortex for a refund. A few things that could make a sprocket wear that fast would be a sandy abrasive environment, not lubing the chain enough, a chain thats adjusted too tight or a sprocket that has sub par metallurgy, meaning that the metal wasn't
heat treated properly. And guys, about the increasing the number of teeth and going faster, I too subscribe to that theory.If the engine dosent make enough power you cant pull the higher gearing and therefore it will go slower.
Two other factors that were not mentioned that play a part in this are
bike aerodynamics and drag. If you could improve the aerodynamics of the bike and also reduce ,ie,wheel bearing drag and tire drag and the like you could pick up some additional MPH with the stock gears.

 

How much of a difference would it make in acceleration in going +2, 3, or 4 on the rear? I am a bigger guy (255lbs.) and don't see losing much weight as I have been this weight since college (football weight). I'd like to be able to pop the front end up a little on accel like the lighter guys can.

 

Despite the obvious benefits with regards to reduced reciprocating mass, would it be such a smart idea to run aluminum sprockets on a high torque engine like the VFR? Wouldn't it have a tendency to wear out quicker, than say, a steel sprocket?

Cliff's Notes: Benefit < Cost:wink: