Enlarged Fifth Gear ?

[Ignacio]

I'm thinking nobody has tried putting a smaller front tire on to mitigate the compromise of the bigger tire with reduced acceleration. I'm thinking a 110/60 ZR17 front would fix everything.

 

[mech 1 twa]

New 6 speed engine. IF you can make everything thing function.

 

[art miller]

Yes, you could absolutely modify the final drive gearing, or put a larger circumference tire on an FJR and it could handle it, but gearing, like almost every other part of life, is one more in an endless series of compromises. You would absolutely get lower rpm at a particular road speed, but other than the needle pointing to a different spot on the tachometer, what does that really buy you?
Do you get a proportional increase in fuel economy? I would suggest that you do not. You may get a minor improvement in fuel mileage, but not the same percentage by which you alter the gearing. There are far too many other variable at play for there to be a 1 to 1 relationship. And, at what cost do you get that mileage?

You will absolutely have worse acceleration in all gears, since the final drive affects the gearing in all of them. Low speed becomes trickier with higher overall gearing in 1st gear and youll need more clutch slipping in parking lot manouvers. And roll on in top gear will be more sluggish, amplified by the 5th gear overdrive ratio.

Smoothness of the engine, and reduction of vibration at cruising speeds is one reason often quoted, but There is a wide range of perceptions and personal tolerance to vibration, and also apparently some variability between bikes. I find that my FJRs have tended to smooth out somewhat when rpms are raised up above around 5000, which coincides with FJR nominal cruising speeds of 85 to 100 mph in stock gearing. The harmonic misbalance of the in-line 4 FJR engine seems worst in the 3500 to 4500 rpm range.

In essence, the increased final drive ratio that occurred between the quicker 1st Gen bikes and 2nd Gen and later bikes is tolerable, but also quite noticeable to anyone sensitive to performance. Like all of our other compromises in life, there is no such thing as a free lunch.

What Fred states is not disputable. Perhaps we can agree, what one thinks is good, another may think it can be better. That is how I perceive this matter. I think having the speedo show true speed is a good thing. Having the taller geared FD has not made my bike less manageable in slow speed maneuvering. The bike runs very smoothly in the 3500-4000rpm range. Spark plugs look clean so not expecting the engine is building vast accumulation of carbon. Never considered cruising at 5000rpm. Unless doing that in 4th gear one is inviting LEO to start writing tickets.

 

[Bounce]

I'm thinking nobody has tried putting a smaller front tire on to mitigate the compromise of the bigger tire with reduced acceleration. I'm thinking a 110/60 ZR17 front would fix everything.

Like the old jacked up up cars of the 70s, you'd always be going downhill?

 

[Ignacio]

I'm thinking nobody has tried putting a smaller front tire on to mitigate the compromise of the bigger tire with reduced acceleration. I'm thinking a 110/60 ZR17 front would fix everything.

Like the old jacked up up cars of the 70s, you'd always be going downhill?

No problem, just put the seat in the lower setting.

 

[Spud]

I'm thinking nobody has tried putting a smaller front tire on to mitigate the compromise of the bigger tire with reduced acceleration. I'm thinking a 110/60 ZR17 front would fix everything.

Nevermind... missed prior posts on point already....

 

[Uncle Hud]

The title of this thread makes me think about prostate glands. And that's really depressing.

 

[Mr_Canoehead]

With the 190-55 rear tire my bike is really unhappy at2500 RPMs in 5th gear. ( Approx 55 MPH. )

I doubt it would pull 2500 RPMs with higher gearing.

Weird, my bike will pull quite happily from under 2000 in 5th (stock gearing). I often slow down to ride through a town at 40mph and don't bother to downshift. It doesn't have a lot of snap but it doesn't surge or lug. I wouldn't expect taller gearing would change that much.

 

[Fred W]

With the 190-55 rear tire my bike is really unhappy at2500 RPMs in 5th gear. ( Approx 55 MPH. )

I doubt it would pull 2500 RPMs with higher gearing.

Weird, my bike will pull quite happily from under 2000 in 5th (stock gearing). I often slow down to ride through a town at 40mph and don't bother to downshift. It doesn't have a lot of snap but it doesn't surge or lug. I wouldn't expect taller gearing would change that much.

“Pull happily” from 2k pm in top gear? No it won’t. I don’t believe it.

Try actually whacking the throttle when you are lugging along at 2000 rpm and tell us about the caucaphoney that occurs from the clattering valvetrain, and then tell us how that’s good for the engine.

Yeah, if you never accelerate you can lug around at idle speed. That doesn’t mean it’s the right thing to do.

 

[dcarver]

With the 190-55 rear tire my bike is really unhappy at

2500 RPMs in 5th gear. ( Approx 55 MPH. )

I doubt it would pull 2500 RPMs with higher gearing.

Weird, my bike will pull quite happily from under 2000 in 5th (stock gearing). I often slow down to ride through a town at 40mph and don't bother to downshift. It doesn't have a lot of snap but it doesn't surge or lug. I wouldn't expect taller gearing would change that much.

“Pull happily” from 2k pm in top gear? No it won’t. I don’t believe it.

Try actually whacking the throttle when you are lugging along at 2000 rpm and tell us about the caucaphoney that occurs from the clattering valvetrain, and then tell us how that’s good for the engine.

Yeah, if you never accelerate you can lug around at idle speed. That doesn’t mean it’s the right thing to do.

What Fred said. Really? I'm the guy who carbonized a valve facilitating an expensive repair bill because of low RPM's on an 06. All while running top-tier fuel. Now, nothing below 3k rpm.

JSNS and https://www.fjrforum.com/forum//public/style_emoticons/default/****.gif

Hugs n' Kisses

 

[Mr_Canoehead]

“Pull happily” from 2k pm in top gear? No it won’t. I don’t believe it.
Try actually whacking the throttle when you are lugging along at 2000 rpm and tell us about the caucaphoney that occurs from the clattering valvetrain, and then tell us how that’s good for the engine.

Yeah, if you never accelerate you can lug around at idle speed. That doesn’t mean it’s the right thing to do.

Hmm, don't believe I said my bike would pull smoothly if actually whacking open the throttle at 2000rpm. I'm talking small throttle openings and having some sensitivity to the feel of the engine.

I was responding the statement that "my bike is really unhappy at 2500 RPMs in 5th gear", which suggests to me surging and bucking at any throttle opening - and describes my BMW's behavior pretty accurately.

 

[Ignacio]

Totally! In fact, I changed mine to a 200 rear tire, swapped a ring gear four teeth taller, and regularly win drag races from stop lights by dumping the clutch with it in 7th gear (I upgraded my '02 ABS just before the Gen 2 bikes came out). It doesn't surge one bit from 0.5 RPM to 12,800...except maybe when I have the sidestand partly down.

But then again I'm running the Wall-E map and have my TPS 3 degrees before top dead center and cam four teeth advanced.

 

[mech 1 twa]

I gotta pee. 54 soon something enlarged and it isn't my d--k.

Can get nasty here at times.

 

[Bounce]

 

[BanjoBoy]

2500 rpm is lugging the engine below it’s designed rpm range. This is not a long stroke V-twin cruiser. Look at your red line. Run the engine at 1/2 of that (or higher up to the limit) and it’s happy. Run it at 2500 rpm and it will wear out bearings quickley, your fuel mileage will suck, and the engine will get all carboned up with combustion deposits. If you want to run at 2500 rpm down the road go buy a bike designed to do that. The FJR isn’t that bike.

^THIS^

I never run below 3,500, 'n my bike's happiest 'round 4K 'n above. Maybe ya just need to tune the thing up so it's smooth above 2500?

With the 190-55 rear tire my bike is really unhappy at2500 RPMs in 5th gear. ( Approx 55 MPH. )

I doubt it would pull 2500 RPMs with higher gearing.

'N if'n ya do need to gear up ^THIS^ is the cheapest, easiest way. (Plus yer bike'll steer better too.)