PERFORMANCE ISSUE??

[Bimmerboy68]

Ok so I bought a Rockster a few months back. 1 owner, low miles. Had just been serviced with new plugs and fluids at a BMW dealer. This bike had set up for at least a year, the fuel lines had broken while riding and BMW repaired them with the steel quick disconnects. So I get it home and noticed idle is low and it runs better on choke. A can of seafoam and fresh fuel and a 1000 miles later and this bike is no better. When taking off at a light giving it wide open throttle it would stall and almost send me over the handle bars. I removed the gas tank and fuel filter, the filter was blocked completely, I replaced the fuel filter, the bike was a little better. So I ordered a new fuel pump, now the bike is a different animal no more bogging on take off, seems like it jumps up to redline quickly, before you know it your running way over the speed limit. I had also adjusted the idle and had found the left side coil was not plugged in all the way. I own a 1999 R1100R and this bike seems to want to pull the front tire off the ground. I did not get but a few miles on the Rockster today, 38 miles in the rain. It doesn't feel like it wants to pull the front tire off the ground. Am I asking to much from this bike or is it more of a cruiser? I will ride the heck out of it another day when the rain has passed.

[peels]

there is no "choke" all that does is give slight throttle to assist in start, and warmup.

power wise. To get the light front wheel feeling, you really gotta rev these things out. and be in the right gear.first gear, cruise at 4500. let off a bit to load the front sup, then nail it to 6500. it'll float. But, I wouldn't do it a lot. its not good for our sideways clutch and splines, in my opinion.

Iv'e done it a few times, just to say I could

[P_Jensen]

It all comes down to the final drive ratio, 1999 R1100 3.0 vs Rockster 2.82. Even
though BMW added a sixth gear they also raised the final drive ratio, the 1150 are tough to get rolling. I had the "Touring" transmission with the .70 overdrive sixth I think all of the Rocksters had the "Sport" transmission with the .80 sixth. The most usefull of the 1150 transmissions is the GSA/Police bike with the 2.38 first gear all other bikes had a 2.05 first gear.

[kirby]

All stock rocksters had a .7 and that is not overdrive, that's less the 1 to 1 meaning every crankshaft revolution will turn the trans output shaft .7 revolution.
The standard r1150r had (99% of them) has a .8 output shaft revolution for 1 revolution of the crankshaft.

None have "overdrive" !

Since there is no primary reduction 1 revolution of the trany input will turn .7 (less than 1) output shaft revolution for the rock and .8 for the roadster.

Then on to the rear reduction. almost always 31/11 stamped on the rear drive.

:-)

[P_Jensen]

Kirby, I think you have that backwards it takes .7 revolutions of the crankshaft to turn the drive shaft 1 revolution or the drive shaft rotates 1.43 revolutions per engine revolution. It takes 2.82 turns of the drive shaft to turn the wheel one revolution, which multiplies the torque by 2.82 at a given rpm. On the R1100 the torque is multiplied by 3.0 that is why the engine would feel stronger, even with less horsepower. 4th gear is about 1:1 consider the speed to rpm difference between 4th and 6th, i.e. 1,000 rpm = x mph. On my roadster with the .7 touring gearbox and 2.82 final drive 3,500 rpm = about 70 mph.

[kirby]

Kirby, I think you have that backwards it takes .7 revolutions of the crankshaft to turn the drive shaft 1 revolution or the drive shaft rotates 1.43 revolutions per engine revolution. It takes 2.82 turns of the drive shaft to turn the wheel one revolution, which multiplies the torque by 2.82 at a given rpm. On the R1100 the torque is multiplied by 3.0 that is why the engine would feel stronger, even with less horsepower. 4th gear is about 1:1 consider the speed to rpm difference between 4th and 6th, i.e. 1,000 rpm = x mph. On my roadster with the .7 touring gearbox and 2.82 final drive 3,500 rpm = about 70 mph.

No I am right.

I know the math is a bit confusing.

If 6tht was 1.43 over crank speed the bike probably would not pull 90 mph in 6th.(not enough HP)

Look up the specs on the R1150R and it will list the 6th gear as .8/.7 and look at the rockster and it will show .7. This means that for every 1 revolution of the input shaft of the transmission in 6th, the out put will either be .7 or .8 revolution. Over drive is when the output is more than 1 revolution of the input. My rock takes 4,000 RPM for 75 indicated speed. 4400 for 80.

No primary reduction so transmission input is engine RPM

RPM X .7 /2.82 X tire circumference (3.14 X Dia) in inches / 12 = feet / 5280 = miles per min X 60 = mph = speed

Try that with .7 .8 and 1.43 shaft speed.

Fact

[P_Jensen]

Kirby;
If you Google the term Motorcycle overdrive transmission, the results are in line with what I am saying. Based on the numbers for indicated RPM's & road speed I think you have the sport trans, the RPM's (3600/100=36 X2=72) on my touring trans were always about 50% of the indicated road speed i.e. 3600 rpm's = 72 mph (120 kph) I would not see 4,000 until about 80. Also anything below 60 mph it did not like being in sixth, the Rockster was a sportier version of the plain Jane R with R1100S forks, sport trans, different gauges, and headlights.

http://www.motorcycle.com/specs/bmw/sta ... etail.html

[kirby]

Kirby;
If you Google the term Motorcycle overdrive transmission, the results are in line with what I am saying. Based on the numbers for indicated RPM's & road speed I think you have the sport trans, the RPM's (3600/100=36 X2=72) on my touring trans were always about 50% of the indicated road speed i.e. 3600 rpm's = 72 mph (120 kph) I would not see 4,000 until about 80. Also anything below 60 mph it did not like being in sixth, the Rockster was a sportier version of the plain Jane R with R1100S forks, sport trans, different gauges, and headlights.

http://www.motorcycle.com/specs/bmw/sta ... etail.html

No you are wrong!!!!

Please don't tell me about the rockster I had one of the first in USA..all had a .7 6th unless special order...few!!!!!!!!

Do the math I laid out!!
A shaft speed to the rear wheel for 1.43 X crank speed at 3600 rpm would be well over 120 mph How can you not see this??? Its a very simple calculation.

BTW

Bought my rockster new and have 195,000 miles.

Does real good to 3000 in 6th

Lets dispel the overdrive myth