2002 1150 diff ratio

[garry a]

Hi I need to confirm the diff ratio on my 2002 1150gs I can't find any numbers stamped on mine I'm looking on the flat face of the breather the book says should be 31/11 I have found a replacement one but guy says it is stamped 34/11 taken off a 2002 1150 adventure last time I drained the oil it looked like silver hamerite and a large piece of tooth came out but still drives ok so need to sort it before it lets me down

 

[DrAlf]

Have a read of this:

http://www.largiader.com/articles/gearing/

According to that a ratio of 34/11 is from an early R1100RS. All 1150 models should have 31/11 ratios. Possible that the final drive has been changed on the donor bike at some point in the past? Either way, I'd go for the same ratio or go higher. I'm running a 33/12 on my 1150 which came from an R1100S. Better high speed cruising.

Good luck

 

[garry a]

I'm beginning to think he read it off wrong as it has the lugs on on it for the mudguard thingy and I don't think the rs would have them

 

[Slipperyeel]

I'm beginning to think he read it off wrong as it has the lugs on on it for the mudguard thingy and I don't think the rs would have them

I'm not an expert on these but is it possible that FD came off an 1100GS instead? Maybe someone with more knowledge can confirm...

 

[Neil W]

those lugs are on the back plate, which is 10 minutes to change over

 

[garry a]

So sounds like only way to really know is to strip and count teeth

 

[ahebron]

Have a read of this:

http://www.largiader.com/articles/gearing/

According to that a ratio of 34/11 is from an early R1100RS. All 1150 models should have 31/11 ratios. Possible that the final drive has been changed on the donor bike at some point in the past? Either way, I'd go for the same ratio or go higher. I'm running a 33/12 on my 1150 which came from an R1100S. Better high speed cruising.

Good luck

It all depends what you want to do with your bike.
I fitted a 33/11 from a R1100R to mine to improve low speed control.


Adrian

 

[DrAlf]

It all depends what you want to do with your bike.
I fitted a 33/11 from a R1100R to mine to improve low speed control.
Adrian

I fitted a 37/11 from an R850R to one of my old 1150's. That's the lowest ratio you can fit. Bike wheelied in 4th gear and topped out at about 85mph. I changed back very shortly afterwards. Still have the 37/11 somewhere. But you're right it's horses for courses and personally a longer ratio is better if you ever go anywhere near a motorway.

 

[Paul Young]

Same here, DrAlf.

I long-since gave up taking my 1150 off-road, but like to be able to hoon so extended the gears by fitting an R1100S FD. I used to hit the rev limiter in 5th, and 6th was too tall to be able to do anything but motorway cruising (the bike slowed down if I changed up to 6th and pinned the throttle...). The taller FD means I no longer hit the rev limiter in 5th and motorway cruising is around 500 rpm lower - perfect The added benefit on acceleration is that I no longer lose drive changing gear as often so, bizarrely, the bike accelerates at least as fast as before.

 

[DrAlf]

Same here, DrAlf.

I long-since gave up taking my 1150 off-road, but like to be able to hoon so extended the gears by fitting an R1100S FD. I used to hit the rev limiter in 5th, and 6th was too tall to be able to do anything but motorway cruising (the bike slowed down if I changed up to 6th and pinned the throttle...). The taller FD means I no longer hit the rev limiter in 5th and motorway cruising is around 500 rpm lower - perfect The added benefit on acceleration is that I no longer lose drive changing gear as often so, bizarrely, the bike accelerates at least as fast as before.

Sounds like you've got the E overdrive gearbox Paul. I'm running a standard Rockster gearbox which has the lower 6th gear. With the R1100S FD I can still rev out in top (on a track of course). My next plan of attack is to rebuild a failed FD with the crown wheel from an R1200C. That gives the longest ratio but I'm still not 100% certain whether it's possible.

 

[Paul Young]

Sounds like you've got the E overdrive gearbox Paul. I'm running a standard Rockster gearbox which has the lower 6th gear. With the R1100S FD I can still rev out in top (on a track of course). My next plan of attack is to rebuild a failed FD with the crown wheel from an R1200C. That gives the longest ratio but I'm still not 100% certain whether it's possible.

You're right there. 'E' overdrive gearbox on a 2000 model bike but I have another in a box in the garage. I might see if that's any different - what top speed do you end up with flat out in 6th (on a track of course...)

 

[Flipfly]

Dr Alf, what revs are you at at say 80mph?

Contrary to others, I like the E box, but my new adv has the standard 6 speed and revs around 500 rpm more which feels a bit buzzy to me, compared to the old E bike. I'd love to fit a final drive to owner the revs but can't figure out which drive I need for this amount of drop.

 

[garry a]

Well I picked up the final drive today and it is stamped 31/11 so all good just hope it all works as it should but thanks to everyone for help and advice

 

[DrAlf]

You're right there. 'E' overdrive gearbox on a 2000 model bike but I have another in a box in the garage. I might see if that's any different - what top speed do you end up with flat out in 6th (on a track of course...)

Top speed with the R1100S FD was 127mph GPS speed on an autobahn. It would go faster but ran out of gears.

Dr Alf, what revs are you at at say 80mph?

Contrary to others, I like the E box, but my new adv has the standard 6 speed and revs around 500 rpm more which feels a bit buzzy to me, compared to the old E bike. I'd love to fit a final drive to owner the revs but can't figure out which drive I need for this amount of drop.

I like the E box too. I'm not sure on RPM FF but when I looked into it the R1100S was the only real option. It makes a huge difference to motorway cruising. With the standard Rockster FD the bike was extremely unpleasant on motorways at reasonable speeds, with the R1100S its greatly improved but not as good as the E box. Have a look at my link above - AFAIK all of the 'C' bikes have a difference FD and as such the R1100S FD is the only plug and play option for longer gearing. Good luck