Gearing felt TALL on my first FJR Ride

[lharrell79]

Ditto to most of the previous posts. I sold a modified B12 Bandit to get the 09 FJR. Initial impression was the B12 would kill it. That was until I learned where the power band was and now know the FJR while about 200 pounds heavier could equal or beat the B12 in straight line acceleration. The FJR is so stable,smooth and with great wind protection it hides its awesome power. It's not as snappy as the lighter performance bikes but for the long haul, comfort,and ability to carry groceries, it delivers what it was designed to do.Bill

Bill is absolutely right. In my book, the FJR does everything well. And yes, it will get the groceries in a hurry.

 

[Pepperell]

The shaft drive tends to let the back rise slightly under accelleration. !!

 

[RPrice]

Ditto to most of the previous posts. I sold a modified B12 Bandit to get the 09 FJR. Initial impression was the B12 would kill it. That was until I learned where the power band was and now know the FJR while about 200 pounds heavier could equal or beat the B12 in straight line acceleration. The FJR is so stable,smooth and with great wind protection it hides its awesome power. It's not as snappy as the lighter performance bikes but for the long haul, comfort,and ability to carry groceries, it delivers what it was designed to do.

Bill

+1, Gunny, Amen!! It is very typical for people to just kinda casually ride the FJR and think that it's pretty tame. I ask, "did you "crank it" over 5k rpm?". When they do it's a whole different perception!

 

[HotRodZilla]

The 145HP your looking seems to be on paper only, or after some mods. Only going off what I've read here, 120s to 130s is a more realistic rear wheel HP number.

What is the weight difference between the two as well?

The VFR is 470 dry -- not a lightweight for a 800.

The FJR appears to be 584 dry.

Really ... real world HP on the stock FJR is 120 to 130??

The above posts are pretty right on. Just don't forget that most HP claims are made at the crank. Not at the rear wheel. So, the FJR is making 145HP at the crank, but loses something like 10% by the time it reaches the rear wheel. The shaft robs more power than a chain, but either way, there is loss.

Don't forget that altitude plays a big factor in butt dyno testing too. Here in Albuquerque at 5000 feet my FJR is fast, but the front wheel will only come up if I work at it (which I usually don't). Last week in Laughlin, I pinned the throttle being an *** and proving a point, and the wheel lifted up quick. She has noticibly more speed and torque at 800 feet.

Either way, ride it and get used to it. It's plenty fast most of the time.

 

[Fred W]

The shaft drive tends to let the back rise slightly under accelleration. !!

Well that would make the gearing feel tall, now wouldn't it!!

 

[Pepperell]

The shaft drive tends to let the back rise slightly under accelleration. !!

Well that would make the gearing feel tall, now wouldn't it!!

Especially if ya drag ya feet!! :lol: Since this isn't about measuring against the clock, and mostly about how the driver perceives it, I think the slight rise offsets the tendency to lift the front somewhat. Might make it seem slower to some. Actually, this is one of the lamest theories I've come up with yet. :dribble:

Disregard.

 

[Bigslim]

You gotta respect the self policing on lame theories.

 

[woodcycl]

UPDATE from the OP:

Okay guys ... I finally have her licensed, tagged, and insured. My wife and I jumped on for a 20 minute ride tonight and I took her back out for a solo 10 minute ride. WOW ... I have a new appreciation for her now and am SO VERY glad!! Sure, she feels different than the VFR under-toe. But, she is plenty fast! Hard to say if I was riding myself side-by-side w/ my VFR which would win in a straight-away 0-100. It would be quite close -- and only because of the extra few things I changed on the VFR. Stock VFR ... would probably lag behind the FJ a bit in my opinion.

And, man ... she rides SO SMOOTH ... hard to even put into words. It is so much easier to ride than the VFR. No knocks on the VFR as I love it, but the FJR is very very nice and I believe I'm going to be very happy w/ her and the powerplant that accompanies her.

 

[carlson_mn]

FWIW I have a buddy who had a VFR800 and he got on my FJR and rode it fairly hooligan style right away, and came back saying it was absolutely much much faster than his VFR. You just have to realize that the bike loves to continue making more and more power all the way essentially to redline.

With the design of the engine, for some reason the bike does have a bit of a flat spot around 3500-4000 rpms so that does tend to kill the snappiness feeling where the VFR does have a steady gain in torque in the lower-mid range. I think it's just how a lot of inline-4s are, have a bit of a dip in the exhaust velocity or something in that area to allow for the surge in the mid and top end. Not going to complain though with the FJR easily lofting the front wheel in 1st gear from 4k rpms rolling on the throttle!

 

[Fred W]

With the design of the engine, for some reason the bike does have a bit of a flat spot around 3500-4000 rpms so that does tend to kill the snappiness feeling where the VFR does have a steady gain in torque in the lower-mid range. I think it's just how a lot of inline-4s are, have a bit of a dip in the exhaust velocity or something in that area to allow for the surge in the mid and top end. Not going to complain though with the FJR easily lofting the front wheel in 1st gear from 4k rpms rolling on the throttle!

Yeah, good call there. I recall seeing some dyno graphs here somewhere, maybe posted by UselessPickles?, that clearly show that dip in the mid rpm range. That is the area that some of the people were trying to get rid of with the air filter box-chop.

 

[UselessPickles]

I recall seeing some dyno graphs here somewhere, maybe posted by UselessPickles?, that clearly show that dip in the mid rpm range. That is the area that some of the people were trying to get rid of with the air filter box-chop.

That would be this thread: https://www.fjrforum.com/forum/index.php?showtopic=120164

I don't want to summarize the whole story yet again, so just don't jump to any conclusions without reading through the whole thread. I'd like to get my bike on a dyno in its current state to see where I'm at now, but I suspect I now have a generally slightly-higher-than-stock torque curve with a more significant improvement in that mid-range dip area (but not as much as the mid-range gain shown in that thread).

 

[UselessPickles]

You just have to realize that the bike loves to continue making more and more power all the way essentially to redline.

Not really. Look at any dyno chart from an FJR. Also, avoid confusion between torque and power. Torque directly translates to acceleration (through the reduction ratios of the transmission, of course). Power is a more abstract concept that represents how much work is done over a period of time, while work is force (torque) times distance traveled (yeah... conceptualize THAT!). Even though the FJR's power continues to climb from 7k to 8k RPM, its torque is already dropping off, so it stops increasing its rate of acceleration well below redline (2k RPM below redline). The increasing acceleration is what you actually feel (and most likely mistake for "power").

Also, don't think that peak torque RPM or peak power RPM tells you anything about when to shift. You have to graph the wheel torque vs. road speed for all gears and see where they intersect.

 

[wheatonFJR]

Thanks for the post and reposting the graphs...helped explain some stuff for me.

 

[saxman]

My buddy used to have a VFR with Staintune pipes and I rode it after I just got my FZ1 and the VFR didn't have much below 6000 on the tach, whereas the FZ1 just walked away from it when both were in top gear at 100kph (about 62mph).(Was that a run-on sentence? - just wondering. . .)

'Course the FZ1 has a dispacement advantage. Still, the honda V4 was incredibly smooth and I found it more stable and planted feeling than the FZ1 - course they're different kinds of rides.

I'm sure my new for me '06 FJR would also walk away from the VFR but haven't had the opportunity to try it yet.

But the FJR is faster than **uk if you unleash it - I saw and indicated 240KPH on a remote road in western Canada and it was still pulling and I thought, hey, my processor (the grey matter between my ears) doesn't have the capacity to deal with the input coming at me so I backed off and got to a more sensible pace.

 

[carlson_mn]

You just have to realize that the bike loves to continue making more and more power all the way essentially to redline.

Not really. Look at any dyno chart from an FJR. Also, avoid confusion between torque and power. Torque directly translates to acceleration (through the reduction ratios of the transmission, of course). Power is a more abstract concept that represents how much work is done over a period of time, while work is force (torque) times distance traveled (yeah... conceptualize THAT!). Even though the FJR's power continues to climb from 7k to 8k RPM, its torque is already dropping off, so it stops increasing its rate of acceleration well below redline (2k RPM below redline). The increasing acceleration is what you actually feel (and most likely mistake for "power").

Also, don't think that peak torque RPM or peak power RPM tells you anything about when to shift. You have to graph the wheel torque vs. road speed for all gears and see where they intersect.

I'll kindly agree and kind of disagree with you on that. In regards to acceleration, HP is HP, regardless of rpm or how much torque is being made at the time. The FJR makes more torque at 4k than at 8-9k but no doubt about it, the acceleartion is faster at 8k. A diesel truck making 800ftlbs isn't going to accelerate very quickly if it can only produce that spinning at 1500rpm; However, it will continue to be capable with a 20,000 pound trailer behind it...

I think the term 'power (=watts)' would refer to hp and 'force' would be torque, right?

We're on the same page, I just generalize things a lot more - a bike that peaks in hp @ 8k and redlines @9k and still makes 90-93% of peak hp at redline I consider to produce well towards the top end. After owning singles, twins, V-4s, and V-Twins I just have that frame of reference compared to the FJR and other inline-4s. And yes, it drives me crazy when people talk about needing to shift at the torque or hp peak... you have to find the sweet spot after the power peak so you don't fall too far down on power where the next gear engages.

Your graphs of acceleration are so linear it seems to just speak for what a smooth and flat power delivery the FJR has. I can't gather a whole lot else from them - no offense. If you can break them down better I'll listen for sure.

 

[UselessPickles]

The FJR makes more torque at 4k than at 8-9k but no doubt about it, the acceleration is faster at 8k.

Actually, the FJR has more torque at 8k than at 4k, but it is quickly dropping at that point. Looks like 8.4k is the point where the torque drops below the 4k level. So that's why it accelerates faster at 8k than 4k. If you are referencing my dyno chart, make sure you're looking at the torque curve for the stock FJR (my modified FJR actually did have more torque at 4k, and did accelerate harder at 4k than at 8k).

A diesel truck making 800ftlbs isn't going to accelerate very quickly if it can only produce that spinning at 1500rpm; However, it will continue to be capable with a 20,000 pound trailer behind it...

But its acceleration at 1500rpm is still a direct result of the torque at 1500rpm, the gear ratio, and the weight of the truck. The RPM doesn't directly matter for acceleration. Whatever the RPM is, acceleration is a direct result of torque at that RPM, the reduction ratio (transmission, other gears), the size of the wheel (which converts the rotational force to linear force), and the weight of the vehicle. There's air resistance, etc. also, but the point is that the RPM is not involved in figuring out the acceleration at a particular RPM.

Force = Mass * Accel

Accel= Force / Mass

Force = (Tq * [reduction ratio]) / [wheel radius]

Accel = (Tq * [reduction ratio]) / (Mass * [wheel radius])

Physics isn't wrong, no matter how kindly you want to disagree with it.

HP does depend on RPM. I won't continue discussing the difference between torque and HP, because it's a confusing topic, and it's easy to make statements about one or the other to be true for the other IF you are making certain assumptions or thinking of them within certain contexts (I can't even think of sensible ways to discuss the differences, because there's too many opportunities for miscommunication).

All that really matters is that when looking at a dyno chart, it's the torque curve that directly tells you how hard the bike accelerates throughout the RPM range.

Your graphs of acceleration are so linear it seems to just speak for what a smooth and flat power delivery the FJR has. I can't gather a whole lot else from them - no offense. If you can break them down better I'll listen for sure.

Are you looking at the same graph as me? The acceleration up to 60mph is very non-linear (looks like a jagged mountain). The reason the rest looks so "linear" is because it's only the trailing end of the torque curve for gears 2-5, and also because as you increase the gear ratio to multiply the speed by a certain ratio, you also decrease the torque by the same ratio. This results in a "longer" and "flatter" torque curve when viewed as a graph of torque vs. road speed.

The second graph is simply showing where the shift points are to get that maximum acceleration through all the gears. It shows the RPMs vs road speed IF you were to shift at the exact right spots. Notice that the shift point is not the same for any two gear changes. There's nothing about a dyno chart by itself that can tell you when you should shift for max acceleration.

 

[carlson_mn]

Where'd you get the acceleration graphs for both the GenI and GenII?

Here's just a graph I pulled from Holeshot.com for example..

So what you're saying is that acceleration should be faster at 4500rpms where the TQ is above 80ftlbs than at 8100rpms, where it falls below 80ftlbs?

 

[UselessPickles]

Where'd you get the acceleration graphs for both the GenI and GenII?

I used the data from a dyno run of a stock gen II bike. It's the red line in this chart:

I have the original DRF file, so I exported the raw data (no human error in reading the chart to get my data).

The max acceleration through all gears data is generated a program I started writing to analyze dyno data in more useful ways and to be able to actually compare potential performance between different vehicles, taking into account gear ratios, weight, etc. The Gen I acceleration data was generated from the Gen II dyno data (with the assumption that the engine hasn't changed), but taking into account the difference in weight and gear ratios between Gen I and Gen II. I believe I assumed an additional 200lbs of rider + gear on both bikes.

So what you're saying is that acceleration should be faster at 4500rpms where the TQ is above 80ftlbs than at 8100rpms, where it falls below 80ftlbs?

I think you're reading that chart wrong. The TQ is below 80 at 4500rpm, but right around 80 at 8000rpm. What I'm saying is that the acceleration is directly proportional to torque (ignoring air resistance). If you're comparing two different RPMs, whichever RPM has higher torque will give you more acceleration, as long as you are comparing RPMs in the same gear.

 

[Bustanut joker]

Oh for **** sakes...

Just ride the fuking thing! If it ain't what ya expected .. sell the damn thing.

Fuking ****.. This place is getting ghey.. :glare:

The constant dissection of this platform is really starting to piss me off. buy a fukin yugo

 

[beemerdons]

Oh for **** sakes...

Just ride the fuking thing! If it ain't what ya expected .. sell the damn thing.

Fuking ****.. This place is getting ghey.. :glare:

The constant dissection of this platform is really starting to piss me off. buy a fukin yugo

+1, Gunny! Sweet dreams Prince Bust and as always from tu Papa Chuy Viejo: Fuzzy Balls!