Sprockets

[Dave Ett]

You'll never get an 18 tooth one on, the 17 is VERY close to the swingarm as it is. You only option would be up to 17 on the front, and down a tooth or two on the back.

Try the 17 front first and see how you get on.

 

[vertically challenged]

Part No.

Dave, what the part number of the 17 toothed sprocket from Renthal, just want to make sure I get the right one.
Thanks

 

[Smythson]

Dave, what the part number of the 17 toothed sprocket from Renthal, just want to make sure I get the right one.
Thanks

I know it's not the renthal one but i was looking at the 650 stock setup - 27717708480 for the BMW 17 tooth.

S

 

[Dave Ett]

No idea, I bought it as a kit from a chap on Ebay. Just specify the F650GS (twin) front sprocket.

 

[vertically challenged]

Cheers.. I'll have a look.....

 

[Smythson]

You'll never get an 18 tooth one on, the 17 is VERY close to the swingarm as it is. You only option would be up to 17 on the front, and down a tooth or two on the back.

Try the 17 front first and see how you get on.

I'm on the 650 with the stock 17T and i never use 1st gear (except when i miss neutral going down)

You weren't kidding about it being tight!

Been on to TT - who replied remarkably quickly - said their 18T is 98mm in diameter. I reckon that's only a few more mm than the 17T. Once i can confirm 17T diameter i may look into shaving the guide rail - i figure the structure of it shall remain completely intact on the inside section and a couple of mm off the outside shouldn't hurt too much...

 

[Richie N]

I just changed the chain and sprockets and went to a 17 front. The difference is very subtle, but the bike feels more relaxed to ride, and the fuelling (throttle response) seems to have improved! Hard to describe but the bike feels like its got longer legs, and theres much less need to go up and down through the box.

Great mod (100% road riding)

Rich

 

[Fordy]

I bought an 17T renthal sprocket and it fouls the swingarm. Not by much, but enough to put the 16T back on

 

[Richie N]

That's odd, is it the right one? Its a great mod for the road and m/ways.

 

[Fordy]

http://www.ebay.co.uk/itm/230721188798#ht_3906wt_952 I think its the right one, standard 17T sprocket for the F650. It went on and turned but each tooth touched the swingarm even with the gunge cleaned off

That's odd, is it the right one? Its a great mod for the road and m/ways.

 

[Richie N]

That's the same as mine - very odd. What bike are you fitting it to?

 

[Fordy]

F800GS, 2008.

Just checked the packet and it states 407-525-17P for a number of Aprilia bikes. Rethal site brings up 407-525-17P as the correct one.

Anyways, I've just emailed the supplier saying I they may have sent the wrong one and will see what they say.

 

[Richie N]

It should have been in a sealed Renthal packet.

 

[Tim Cullis]

With six gear ratios to play with there shouldn't be any difficulty whatsoever in having a box that combines a low first gear for offroading and a high top gear for effortless cruising.

However... some bean counter at BMW thought it would make sense to use the close ratio gearbox off the 800S/ST on the 650/800GS.

 

[Fordy]

Packet was sealed when I got it, and markings on sprocket confirm a 407-525-17 was supplied.

A&R have offered a refund, but I'm going to try an Afam sprocket from them first.

 

[MikeMike]

Tim, I've got a 658 and would like to drop the rpms at cruising speed, any recommendations? Looking for a drop of around 500rpm if possible and willing to sacrifice acceleration because it has enough for me and I can always snag a gear lower on the highway if I need to get some extra oomph.
Up or down on the motor end? One tooth or two? Any particular brand?
Thanks for input from anyone.

 

[Dean]

As posted previously "How Funny that we are all different" is so very true to say.

My take and having looked into my ride F650 GS (K72) is the fact that, Compared to the original 16 teeth front and 42 teeth rear (F650(Twin)GS: 17/41), combined 15T front plus 47T rear results in approx. 10% reduction in speed and 10% increase in torque.

I have come to the for me conclusion that I,m perfectly happy with the way the bike is and performs In standard sprockets. and of course the fueling that it provides so why change


I have looked at the machined lighter sprockets Holes but thought then again no the standard form suits very well.

I know It'd different on the F800 and the OP is referring to the F8 and many like a different sprocket off of the F650 due to how it sits on the motorway, then again it is far less road biased

 

[SuperTed]

It looks like a good idea...

...but if you are happy with the way the bike rides as standard why change it
Having read the threads on this I got a 17t sprocket just before going to the Orkneys last month. Worst thing I could have done.
The improved mpg is marginal and I was still filling up at about 200 miles and it still cost about £20. Plus the drop in cruising revs put the frequency of the vibes through the bars at a point where my hand went numb in about 25 miles. No great on a 1650 miles trip
I've been riding my 800 since October with no probs, so the 16t is going back on it in the morning.
If anyone wants a TT 17t sprocket...

 

[tosh23]

Ive got to get the seized one off first...Its seized solid so i'm going to have to grind/cutting disc it off.....getting a slide hammer/puller will fubar the bearings in the g/box..

 

[MikeMike]

Tosh, is there some sort of puller you can use first?