Making a Gen II faster (swap middle drive from Gen I ?)

[Fred W]

Wasn't the point of the VMax drive swap to raise the gearing for lower cruising rpm? 'Cause that would be exactly opposite what the OP wants. Or am I thinking of a different final drive gearing swap?

 

[Cosmin]

Yes, I think he wanted by swapping the final drive (with a Vmax one) to make the gear ration 'taller' - opposite to what I was evaluating

And below the promised table with performance figures for various bikes measured by German 'Motorrad' magazine; the figures for 1200RT and 1200GS are referring to the latest models (125HP - water cooled). In real life I think the first table (top gear roll-ons) is the most relevant (at least for me

) ). It's interesting the big progress made by 1200RT and 1200GS: previous air-cooled engine (lower powered) generated much worse figures but I suppose that the below figures for these 2 bikes are severely affected when you add weight (luggage and passenger) due to much lowest torque in the comparison list.
Going back to the FJRs - I think for Gen I they used a 2002 model on which they made also a 100.000km reliability test (passed with minor issues); performance figures (displayed below) after 100.000km (~62.000 miles) were slightly better than the ones measured at 1100 miles. According to the same measurements it seems that indeed the FJR got slightly slower with the newer generations (FJR III below is the 5 gear model)...
Another conclusion is that the BMW K1300GT is the fastest tourer ever made but, unfortunately, the worst model from BMW in terms of reliability (I think it had the biggest number of recalls).


1600GT 1300GT 1200RT 1200GS FJR I FJR II FJR III GTR1400


60-100 km/h 3,7 3,5 3,9 3,4 4,0 4,4 4.7 5,6
100-140 km/h 3,9 3,5 4,2 3,8 3,9 4,5 4,6 5,0
140-180 km/h 4,1 3,6 5,4 5,2 4,2 5,2 5,5 6,4



0-100 km/h 2,9 3,1 3,4 3,6 3,0 3,3 3,2 3,2
0-140 km/h 5,0 4,8 5,8 5,8 4,9 5,4 5,6 5,2
0-200 km/h 10,2 9,0 13,4 14,4 9,7 11,9 12,2 10,4

 

[RossKean]

Back in my Venture days, some guys were swapping VMax RD's in to increase the RPMs and improve acceleration at the expense of higher cruising RPM. The Venture RD apparently reduces RPM for the FJR. So, how does the FD ratio compare between the FJR and the VMax? (might be pretty similar)

 

[Cosmin]

Thanks but after a quick check it seems that the VMax and the FJR have identical FD ratio: 9 by 33 teeth, so improvement...

 

[HotRodZilla]

Two words: Down Shift.

You're welcome. Now, please send me half of the $1500 it would have cost you to change out your gears for a teeny bit of power.

 

[BugR]

Its not the Vmax rear drive you want its the Venture rear drive. I have one, was going to swap out the internals (its not a bolt on replacement) but the procedure is tricky.

Chris

 

[PapaUtah]

Here is a fairly easy solution to your dilemma...

 

[RossKean]

Its not the Vmax rear drive you want its the Venture rear drive. I have one, was going to swap out the internals (its not a bolt on replacement) but the procedure is tricky. Chris

I thought the idea of the Venture RD was to reduce RPM in the higher gears for (theoretically) better MPG at highway cruise. Sort of like a 6th gear? (I'm quite possibly mistaken) This would serve to make the perceived performance worse, not better - unless the owner made a point to stay one gear lower all the time. (Keeping the revs up by downshifting as suggested by HRZ)

 

[Cosmin]

I don't have the figures of Venture FD ratio, most probably it will cause a 'taller' gearbox, which is opposite to what I was searching. VMax also has identical FD ratio, so no improvement in that direction either.

The initial discussion started from the need of additional power/torque (mainly needed for top-gear roll-ons but also for overtaking). One idea was to install the middle gear wheels from a Gen I for slightly higher rpm in all gears (and slightly better performance) but it was concluded that the main factor for Gen I better performance was weight difference (plus the shorter gears).

 

[SLK50]

Installing a smaller diameter 190-50 rear tire might give you

the results you're looking for.

I went the other way, going for a 199-55, trying to raise the

rear end a bit to help keep the pegs from dragging.

It effectively made the gearing a little taller. As a result I

spend a lot of time in fourth gear especially when riding

two up. I can barely use 5th gear below 55 MPH.

 

[Mr. BR]

This should help...

The FJR and Vmax share the same FD (final drive) ratio: 9/33 or 3.66:1 (but the actual FD units are not inter-changeable if I recall correctly)

The Venture Royal Star has this FD ratio: 10/33 or 3.3:1 (or 10% "taller" than the FJR/Vmax).

The venture folks like the FJR-VMax gears to get a few more revs and better performance as they're often heavily loaded + passenger.

Some FJR owners like the Venture gears in order to reduce the revs about 10% for a little more relaxed feel a freeway speeds (I have this on my '05).

Any gear change requires the NEW gears to go in your existing model's FD case.. none of FDs are a direct swap between bikes (ie, an FJR-VMax FD to a Venture.... it won't fit).

Regards,

Mr. BR

 

[BugR]

Oh crap, yes you are right, my goal was to lower the rpm for any given gear to improve 5th fuel consumption when riding slab.

Venture ratio is going the wrong way. I still think shifting down on the FJR or go for the 1600 is the only way to solve this issue.

Chris

 

[Fred W]

I'm with you on that, BugR. I do sometimes get a little lazy now and then, especially with the missus on the back. In the name of smooth riding, slow and early shifting makes for a very smooooth ride, but maybe not the most exciting one. Then you get on a good set of twisties and run the R's up to between 6k and redline and the bike really comes alive. It's a whole 'nother animal!

Yeah, FJR's got good 1300cc torque down low, like 3000-4000 rpm, and you can ride it down there all day long with no risk of damage to the bike. But when you do wick it up to twice that rpm, well the bike is a whole different animal.

How cool is that? You have got two totally different character bikes all in one!

 

[garyahouse]

Just my opinion:

Don't just write off the NOS suggestion above. You inject more oxygen under the right circumstances and you get the power you're looking for. Typically it activates under full throttle only. Any other solutions provided here are going to give you marginal improvements at best. Two questions come to mind: can/will they do it for the FJR,, and are you willing or able to pay for it? I did a quick scan of the website for the first hit that popped up on Google: a company called JMS. This is not an endorsement: I have no horse in this race. Just a suggestion.

For example, they advertise on their website that they have/are:

• Two full time, experienced automotive/motorcycle mechanics
• Motorcyle Performance experts
• Nitrous Oxide experts
• We install everything that we sell
• The staff in our design & fabrication department can work with you on any custom fabrication project you have in mind.

Seems like one quick google search and a subsequent phone call or email might answer your question if you choose to go this route.

We'd certainly love to hear all the details if you decided to try this out and they were able to give you what you were looking for.

For me personally, I'd agree with Fred above. I'm good with what I've got.

Gary

darksider #44

 

[extrememarine]

I'll have to hunt for that one - I was with him when we flogged his bike on the dyno; actually, I flogged his bike on the dyno while he made changes with the EFI programmer. We did 3 runs with my bike on the same dyno / same day as a baseline. It was interesting, but the net was that my 5k mile bone stock '09 made within .5 hp of his iirc.

Where is that thread that Useless pickles did. He tried everything I believe to get more power.
Dave

 

[Bustanut joker]

And after all that we went drag racing and the results were less than stellar.

 

[BugR]

I know I am an old fart but I would probably *hit myself if NOS kicked in when I hit WOT on an FJR.

Where could you possibly want that power on the street?

 

[Cosmin]

Additional conclusions:

1) tire installation: 190/55-17 might bring about 1.4% rpm increase (shorter final ratio). If I combine that with middle gears swap (~3%) it results ~4.4% rpm increase at the same speed (or 4.4% 'shorter' gear). Though The 190/50 rear tire might affect a little the handling on curvy roads, perhaps it's worth a try at next tyre change...

2) final drive wheels replacement: it will not help (the ones available from Venture reduce rpm, do not increase it);

3) NOS - I evaluated it in the past but it seems to complicate the overall setup quite much, so it's not my preferred solutions;

4) Useless Pickles - so it's confirmed that various PC III+K&N+Sport exchaust etc won't bring a significant improvement;

5) @BugR - As I said, the need for additional power comes since almost all the time I ride with wife plus lots of luggage. Perhaps for most riders FJR power/torque are enough since they ride alone. Also my bike is enough for me for single riding but when I load it (almost all trips) things are different.

 

[Fred W]

@Cosmin - In the above summary you forgot to mention the best advice you got so far in this thread. The best way to get more power under most any circumstances, when riding 2-up or riding solo:

Down shift! Don't be afraid to run those revs up. THAT is where the scary fast power lives.

 

[RossKean]

^^^ Yes!!

The FJR behaves very well at 80++ miles per hour in fourth! (Even in third if you want a really exciting ride) It might be a bit buzzier and will definitely hurt at gas pump. Why try to use other methods to reduce the final drive ratio when the transmission does this very well.

Note: A 195/55-17 is actually a little larger in circumference. You would need the 195/50-17 (or 190/50-17) to increase RPM at a given speed. (VERY little change in either case)