FJRiders.com

N4HHE wrote: ↑Mon Mar 20, 2023 12:12 am

Dan Cooper wrote: ↑Sun Mar 19, 2023 10:25 pm Uh, gee Ray, the videos I've seen tend to show the helical gears in the 6 speed gearbox are constant mesh design with only the engagement dog ring moving instead of any gears moving. Have I missed something??

Yes, even the straight cut gears are constant mesh. But helical have a "problem" if the shaft is not turning it has to turn a little bit as the gear slides into full mesh due to the angle of the helical cut. When spinning this means one has to change what is probably an insignificant RPM, to speed up or slow down 2° of rotation or something, and little things like this are often felt.

At the risk of being redundant, let me repeat, the gears are always in full mesh. They do not "slide into full mesh". In the 6 speed, only the engagement dog rings move side to side. And just like in the straight cut gears of the 5 speed, or any other scooter transmission, sometimes the DOGS do not line up exactly with the holes if the shaft is not turning, as in at a stop. If the scooter is moving this should not be a problem. That said, Yamaha has not been known for having the slickest shifting gearboxes and some are worse than others.

The helical cut gears have two purposes. One is to provide more gear tooth contact area to make up for the slightly narrower gears in the 6 speed vs the 5 speed. Even at that, second gear proved to be a little weak initially. But if you remember, Yamaha and others have had second gear problems in the past. The other is to reduce gear whine noise.


dan,


And that's all I've got to say about that. Forest Gump

The helical cut gears are fully engaged/meshed all the time, the same as the old 5 speeds with straight cut gears. The gears themselves never move back and forth. When you shift you move a slider with dogs that moves out of one set of gears and slides into the next set of gears. This sliding disengages one gearset to freewheel on the main shaft and when the dogs engage the next gearset, it locks them to the main shaft. These dogs are much wider than gear teeth and require the accepting gearset to move to engage. If I understand correctly, I think you guys are saying that the helical cut gears require more force to get to move the small amount to engage the dogs, versus the straight cut gears. Am I understanding this correctly?

Also, I have one more question. I think that clutchless shifting and traditional speed shifting are two different things. Speed shifting, as I have known it, involves keeping the throttle pinned at WOT while fanning the clutch and making the shift with great haste. Clutchless shifting is not done with constant WOT. A slight throttle reduction (just momentary) is required for the shift to engage smoothly. Are you saying you're wanting to shift clutchless at WOT without throttle reduction?

You all are obviously way better riders than me...to save the portion of the second to not use the clutch hand.

After riding 40 plus years with a clutch, my little ratbrain would get a cramp if it decided that on this one particular shift, to not use the clutch... like I do 99.9999999999999999% of the time.

I'll just stick in the slow lane and watch all you young whippersnappers pass me by.

lol

I would never do this, but I've heard, through the grapevine, that preloading the shifter then fanning the clutch is an excellent way to unload the transmission just enough to not kill the shift dogs while still allowing a good power shift. Same affect as a momentary roll off without the driveline shock.

Agree with the above. I just don't find it necessary to flog the equipment that hard anymore. At normal acceleration rates, preloading the shifter makes the shifts buttery smooth, even on the BMW GS. The quick shifter on the 21 GS, Eh, not a big fan. I share Wheaton's rat brain and can do better shifting normally. Might be nice for downshifting into corners on the Cherohala. Haven't done any of that yet.

Well, we can harken back to the days of Gen2's (and maybe some Gen1's) that had second gear jump out under hard acceleration. The gear dogs wear and will slip out if worn enough..... requires splitting cases to fix that.... ask Festus and Viper Dad what they went through. The '06 project FJR I had did have it's 2nd gear replaced also. Also my buddy's '10 had it done..... That said, I use the clutch 99.99% of the time and make sure the 1-2 shift is positive.
Likely got nothing to do with the 6 speed issue, sounds like the gear dogs need to slide easier??

Lots of good chat here.

Ray, I did have a clutch soak done by the dealer year one or two of ownership - no change.

Everything was also reinspected when I had the transmission recall done.

I am hopeful that a different oil and maybe different weight will help smooth things out. Currently in discussions with the fine folks at Yamaha.


Canadian FJR

I've had really nice shifting in all my bikes using Mobil 1 Racing 4T Syn. Seems to take the shearing forces better and shifts smooth longer.

Just for $h!t$ and giggles, I gave the clutch a real good flushing and took my time to ensure it was bled well.

Not sure if it was the cooler weather or the fresh clutch fluid but the shifting is definitely smoother.

Stay tuned, more testing to come.


Canadian

Odd. I'm not on the track, so I use t clutch like the designers intended.

Good idea on the flush, the line runs inside the frame right beside the engine, so sees a lot of heat cycles. Actually, the brake lines are inside the frame beside the engine as well....... good idea to flushy every year. Also check brass bushing in clutch lever, if worn, replace and grease with silicone grease that won't wash out easily.

First time I had the fairing off since the recall. Seem to have a slight oil leak. Need to determine where it’s coming from.


Canadian FJR

Go for the obvious...... half moons on the valve cover gasket??

My current 2021 (6-spd) shifts nice. Not quite as nice as my most recent '14, but plenty good enough. Ironically, on the '21, the harder I accelerate and the higher in the rev range I shift at, the BETTER/SMOOTHER the shift.

Therefore, in the interest of preserving the transmission.....

Anyone shifting without the clutch? Had my track day coach tell me I need to work on it, started doing it on the FJR and it shifts great without the clutch. I still have to remind myself to do it but I'm trying to do it more and more. It's very nice.

I would advise given the FJR history, 5 or 6 speed, no clutchless shifts between 1st and 2nd.... and make it a positive shift.

“Go for the obvious...... half moons on the valve cover gasket?”

I’ll double check but it looks like around where thr bottom case and upper join.

Canadian FJR

“Anyone shifting without the clutch? Had my track day coach tell me I need to work on it, started doing it on the FJR and it shifts great without the clutch. I still have to remind myself to do it but I'm trying to do it more and more. It's very nice.”

Yep - smooth as silk on both my 03 and 18.


Canadian FJR