I think there is some confusion about how this is usually accomplished. It would be rare (and fairly expensive) to completely re-manufacture a transmission to change out the number of gears or change their stock ratios.

Nearly the same effect can be obtained by simply changing out the front or rear sprocket (or both) on the final drive. This can be done with a fraction of the expense and trouble of redesigning a transmission to accept non-standard gearing.

 

I don't mean to make a thread on how to change gearing, but what the best final gear ratio would be;
In case I want to buy a bike, I kind of have an idea, of how fast the engine runs at eg: 60MPH.

Perhaps get some numbers like: 'my bike has a final gear ratio of 9:1 or whatever, or something...

 

The factory gear ratios on modern motorcycles generally give a optimum balance between economy and acceleration. The engineers that design the powertrains spend a lot of time and money testing and researching what the best balance is for the average rider of any certain type of motorcycle.

For specialty use, such as a non-touring motorcycle that will be doing an above average amount of highway riding, or a stunter who wants to be able to easily perform wheelies with less clutch wear, changing the final drive sprocket ratio makes sense.

Since every model of motorcycle is different, with different final drives and transmissions, there will be no hard and fast ratio that will work well with every motorcycle.

Small changes to the stock configuration such as one or two teeth on a sprocket are generally the extent of modifications.

 

I read a lot of people prefer their bike to have a final gear that's higher, so their engine will do lower RPM's on the highway!

If you want lower rpm on the freeway, can't you just shift up? Or how low do you want your rpm to be?

I don't want the rpm to get very low on the freeway, because you need the "sudden extra speed" when a car doesn't see you and you need to move quickly. I think I do 8000 rpm at 80 mph, which is ok for me. That's in 5th gear, not in 6th.

 

I'm already in 5th gear, and it feels made for driving between 35 and 50MPH, not for riding 75MPH.

 

Most likely you just need to get used to it. I am not sure what your experience level is, but if you are new, the sensation of actually hearing and feeling a motor especially one that is at higher revs will be new to you as well.

People who are used to cars, get used to rarely hearing the engine. When they get on a motorcycle, all of a sudden they are hearing something they have never heard before, which concerns them.

Modern motorcycle engines are made to rev. It's OK. You are not hurting it. If the vibrations bother you, thicker gloves, better handgrips and boots with vibration absorbing soles and vibration absorbing foot pegs can help.

 

+1 on getting used to it. My VS800 Suzuki turns about 5000 rpm at highway speeds, which many new to it think is screaming. But, it red-lines at about 8500, so 5000 isn't actually much. My old CB450 is closer to 6000 rpm at the same speeds, and red-lines at 9500; it feels like it is wound up, after riding the VS800 a while. In both cases, dropping the rpm by 20% at the same speeds would probably lower the mpg, because the engine would be laboring more, so running less efficiently.

 

In both cases, dropping the rpm by 20% at the same speeds would probably lower the mpg, because the engine would be laboring more, so running less efficiently.QUOTE]

I used to believe this as well,
however I've learned from my car (which has an onboard MPG counter), that going to higher gear ALWAYS saves MPG (meaning at similar acceleration).
Even when you're pushing it, even with a turbo, a car can accelerate faster in smaller gear, but it will use more MPG's than on a higher gear.

As far as getting used to it, perhaps that is true.
However if I could run my engine at 1.5k RPM, instead of 4k RPM, I would.

On racing bikes, those that top out at 11k RPM, it feels more natural, than on a cruiser. I don't know what the top RPMs are on a 2005 Honda Shadow, but presume it's somewhere between 7,5k and 8k rpm.
When it is so, then I don't like riding at 5k RPM; but would feel more comfortable at half that, even if I had little acceleration or torque at those gears.
I could always downshift to a lower gear if I needed more power!

 

You need about 1500/1600cc's then you can cruise all day long at 80mph turning about 3500 rpm's. I also will suspect that you would come up with a reason to complain about how heavy it is. You have a good motorcycle, not perfect but there isn't one that is. There will ALWAYS be something you don't like. Most motorcycles are buzzy at some speed/rpm, just like others vibrate sitting at a stop sign. By reading a lot of your posts, I think you are really suffering from buyers remorse. Is the Shadow the overall problem??

 

It has 3x the power of my 250cc scooter, and my scooter had nearly the same RPM's.
The scooter engine just was pushing the bike harder.
Same could happen with a Shadow. Initially I did have buyers remorse, however now that I have my bike, bought some saddlebags, and a small windshield, some risers, it feels a lot more like the bike I like.
And when I hopefully have my friend paint the mudguards, and tank to white, I'll most surely love the bike even more.

I read it's possible to do something about the gearing to get it going lower RPM. For me personally, I think it has plenty of power in 5th gear. If I could convert some of that into lower RPM (or even higher speed; though I don't need the high speeds) I would be happy.

 

The Shadow 750 doesn't have 3 times the power. As much as I despise scooters, those 250cc scooters have a surprising amount of power due to the fact that they only weigh like 275-300lbs.

-You are certainly trying to get the square peg into the round hole on this bike aren't ya?

 

my 260cc scooter had only 14HP and about that much torque.
I thought to read, that the Shadow has 57HP.
That's 4x more power.

 

Its listed at 43 horsepower but weighs 600lbs. Its faster than your scooter, but not by THAT much.

 

Ok, first off, is this a 750n or 1100 Shadow? I will assume that it is a 750, just because it won the ****ing cointoss.

Now, a Shadow 750 weighs in around 540lbs wet. (unless it is the RS, which I believe only weighs 510 wet)

Stock power on every Shadow 750 made from 98 onward (do not know about earlier years averaged between 36 and 43 advertized. 98-03 ACE's topped out at 5700 rpm, while the 02-05 Spirit 750's would turn to 7k.

Now, my modified 750 ACE weighs in same weight as the RS, pushes out about 60 at the rear tire, and cruises a little over 4k RPM at 80 or so with the stock 17t front and 41t rear sprockets. My Shadow would do nicely with a 37t rear, where as it is light (for a cruiser) puts out a good deal more power than stock, and does a lot of highway miles. The 38t sprocket is one of the most popular mods done to the chain drive Shadows, to give it a bit lower rpms at speed.

sorry if I seem unorganized.... unable to fall back asleep, and tired as **** right now.

 

My scooter was Fuel injected, however it had hydraulic valves, meaning no valve adjustment is necessary. However it saps a lot of power, or so it seems. There are similar scooters that have 18HP, or 20HP for a 300cc; but those are with regular valves.

Well, not to get caught onto the details, the fact is still true that a scooter has way less power at almost the same RPMs.

I did hear about that it's possible to change the gear ratio.
(changing the chain and sprockets and stuff)
How much on average would it cost on parts, and perhaps labor?

 

I finally got the rear sprocket adjusted, to 38 (I believe from 40 or 42).
It was something really I'd recommend.

On other forums, they actually recommend going with a 37 or even going with a 36!

So far, only the first gear is a bit long, the rest is ok! (before the first gear was fine, but all the other gears where too short).
Even now, I sometimes find myself in 2nd gear for only a second or two.

With the 2 tooth off the rear sprocket, the RPM's feel much more like cruising, rather than the feeling of being on a racing bike (on a cruiser).

It feels right to shift to 2nd gear after going 15-20MPH.
@40MPH, in 5th gear, the engine does ~1000RPMs, or just about the lowest you could put it. Also at 4th gear, it doesn't feel like you're revving the engine.

One of the mechanics actually recommended enlarging the front sprocket with 1 tooth (that is, if there was sufficient spacing). I wished I had done that, (as the ratio is 1 to 3 compared to a rear sprocket); however they did not have a front sprocket in stock.
Still, if I would recommend anyone to change the rear sprocket on a '05 Spirit 750, I'd recommend a 37T; or if even possible, just change the front sprocket.

It feels like I killed 3 birds with 1 stone:

1- Better gear feeling, at least for me (better for cruising, less for racing)
2- Lower RPM, means higher MPG (and since the bike still has plenty of power, I don't mind trading some for MPG's)
3- It seems because I'm running in lower RPM's that there's less backfiring.

Thanks for your opinions, they have helped a lot!

So far, I've installed a riser extension piece, a Spitfire windshield, and bought 2 saddlebags. After that, I probably will paint the mudguards and tank to white.

 

You cannot put a bigger front sprocket on an 05 750 Spirit. (For some reason, I thought you has an Aero)

On the 750ACE forums, the 38t sprocket is the most recommended size to go to. I myself have been wanting a 37t.

With the increased power, and if I can get the lightweight aluminum rims I want, the bike should take off like a rocket compared to how it does now. (It feels like it has way too big a sprocket as it is with the 41t, I can easily start off in 2nd)

I think you'll be quite happy with the new sprocket.

 

You think with a 38T sprocket, how much would my MPG's go up/dn?
According to the math, 5-10% change, should result in 5-10% MPG? (if so, my 48MPG could go to 50 or even 52MPG).

 

You will not get the same % increase in mpg as you reduced rpm; it doesn't work that way. You still need the same amount of power at whatever speed you choose, and the only difference is a little less parasitic loss from the lowered rpm. If you get a 1% improvement, that would be better than I'd expect. Of course, if you believe you'll get better mpg, you will, because you'll ride in a way that improves mpg. Once you return to your normal riding style, the mpg will likely be little different from what you get now.

 

Unfortunately I've never kept track of MPG's because I just bought the bike. However I can keep track on fuelly with it, to see the avg MPG.
It's probably going to be ~45MPG in the beginning, because I'm experimenting with it.
After a while, I'd probably get 50, perhaps 55 if I'm lucky.

 

I have seen owners of Shadow 750's get regularly 50+ mpg. If you drive conservatively, you can as well.

Myself, I get under 40, but I drive mine like it was stolen! LMAO!!!

 

My 07 Shadow Spirit 750 got 55-60 mpg like clockwork. The 1300 Interstate gets about 45.

 

Indeed, my 05 shadow spirit had ~55MPG's riding normal, and ~64MPG's riding mostly on highways.