RPM`s

[camper]

Hi to all....Enjoy reading this site so I decided to register. I`m from Montreal, Canada and no XS clubs up here therefore information is very hard to get. I own a 1980 XS1100 . I`m wondering if I can get some help from anyone .

PROJECT: (For this year anyway...)

I would like to know if it`s possible to bring down the RPM`s while crusing the highways.......Is there a way to MAYBE change the rear differential ??????? to bring down the ratio...........
Has anyone tried this project ???? and if yes was it worth the hassle ?????

Thanks in advance

Norm

[John]

RPM's

Hey Norm, That question has bounced around here a few times. I posted it a few weeks ago also. I ride an 80 Special, and it has a 16 in rear wheel, vs the 17 that is on your bike, so mine revs higher than yours at freeway speed. The middle gear drive from a Yamaha triple was discussed, but one of the guys here that owns a triple did some research, and that won't work either. Looks like we're stuck with what we got.

[pgg]

Camper, from what I can see, about the only feasible way to alter your gearing is to dig deep into the guts of the gearbox and exchange the middle drive, middle driven and final drive cogs with custom built cogs. I'm currently trying to get motivated to try the operation. Realistically, the only reason you'd want to do this is to burn off the cops if you're getting chased.

Dunno about over there, but down here if the cops clock you at 50kph over the open road limit they'll impound your keys and revoke your licence for 6 months or so. Bad news. If you're out on an open stretch you're gunna need at least 230-240 kph to do a decent runner. It's either lose the cops or lose your licence. Once you find some backroads you're pretty safe as the old xs11's acceleration will blow any cop car into the weeds.

Once out of sight you can usually find somewhere to hide. Lying your bike on its side behind thick bushes will work. Also, try hiding up driveways or behind buildings. Hope like hell the heat seeking chopper wasn't called in.

If you're happy cruising at legal speeds, then changing your gear ratios wouldn't really be worth the hassle. The bike doesn't even start to wake up and stretch out until about 5000 revs anyway.

[TheDjost]

But even at legal speeds, the RPMs stay up at 5K. You don't need to have the engine revving so high. I would think that 3K would be more than enough to hold your speed, and it would increase the range per tank.

Here are the main reasons to decrease the RPMs:

- Increased range
- Less vibration and noise while crusing
- less engine wear / heat

The best would be to have a 6th speed, but....

How about just changing just the 5th speed gears inside the transmission? I have no idea how the yamaha transmission is built, but I know it's something that is routinely done on suzuki swift cars to play with engine RPMs in 5th. Some people want to raise RPMs, some people want to lower them, but it's a relatively easy job on the swift transmission.

-Justin

[pgg]

The standard xs does around 15-16 mph @ 1000 revs in top so I reckon the ideal revs would be 19-20 mph @ 1000. That'll give you about 150 mph at 7500 in good conditions - you'd cruise at 60 mph @ 3000. A tweaked piped and jetted motor would help keep the acceleration strong.