FJRiders.com

[quote=fontanaman post_id=133251 time=1608001596 user_id=236
If the tranny fails does this mean I get to find out how good the slipper clutch is?

[/quote]
The way I figure this is if the engine locks up you "get to find out how good the slipper clutch is" but if the transmission locks, you're still SOL unless enough stuff breaks to allow the wheel to turn.

Here is a quote from a news release from Germany (translated):

"... newly programmed engine management system that limits the engine speed when idling and minimizes load peaks during gear changes...."

Perhaps the idling change is to prevent jamming it in gear with the motor revving at 8,000 rpm?
Minimizing load peaks during gear changes.... hmmmmm.

So IIRC, the 6-speed uses straight cut gears instead of heli-cut gears, to save case space. My understanding was that the straight cut gears may be noisier, they aren't inherently less strong?

This inquiring mind wants to know....

Hppants wrote: ↑Wed Dec 16, 2020 2:11 pm So IIRC, the 6-speed uses straight cut gears instead of heli-cut gears, to save case space. My understanding was that the straight cut gears may be noisier, they aren't inherently less strong?

This inquiring mind wants to know....

Helical gears are stronger for sure, but I don't know which gears you speak of that were helical and are now straight. All the main gears in the one I rebuilt were straight, and that was the 5 speed version.

Hppants wrote: ↑Wed Dec 16, 2020 2:11 pm So IIRC, the 6-speed uses straight cut gears instead of heli-cut gears,

I thought is was the other way 'round... From a revzilla article/review of the '16 FJR dated May 2016...

"Yamaha redesigned the gearbox with new helical gears replacing the old straight-cut gears."

Hppants wrote: ↑Wed Dec 16, 2020 2:11 pm ...
So IIRC, the 6-speed uses straight cut gears instead of heli-cut gears, to save case space. My understanding was that the straight cut gears may be noisier, they aren't inherently less strong?

I think you will find it's the 6-speed that has the helically cut gears (see the picture in raYzerman's post above).

My understanding is that the helical gears have a smoother engagement than the straight cut, even though neither will have any significant sliding of the teeth.

[pre edit: I see a lot transpired while I was typing.]

Limits engine speed when idling: Dunno about that one. It's surely independent of transmission problems unless it is intended to limit revving up the engine and dumping the clutch. This is probably and entirely different issue that Yamaha has bundled into the recall.

Minimizes load peaks during gear changes: If the ECU can detect when the clutch is pulled in or the shift lever is actuated it can alter spark and FI timing to slightly unload the engine and facilitate shifting. This is a common practice and many racing aftermarket kits exist to do this for clutchless shifts.

Straight cut gears: (Spur gears) Noisy, with a high pitch whine (like some of our Forum members...). A helically cut gear set has more surface contact area (meshing area) to distribute the forces, which makes them slightly stronger than spur gears. Helical gears also produce more heat than spur gears because of the long sliding surfaces.

In a motorcycle there are two rows of gears, engine driven gears and output gears. One set of gears slide on a shaft and are moved left and right by shifting forks. This forces the dogs (protruding nubbies on one gear) to engage in the holes in the other gear, thereby locking a driven gear to an output gear. It's important to understand that the gears are moved left and right by the shift forks.

Here is the big thing with helically cut gears -- because of the angle of the gear face it makes the gears want to move axially, right and/or left depending on the direction of the helical cut. You now have the helical gears forcefully wanting to move in one axial direction while the shift forks may be working against this trying to slide the gears to change ratios between the driven and output gears in the other direction.



Because of the high torque produced in second gear it will have very high axial loading. This may be a contributing factor to the shift forks burning and the gear dogs of second gear becoming rounded off, especially if the axial load is moving in one direction and the shift fork is moving against it. Maybe someone that has been in the transmission can see if this is the case.

A solution better than straight gears, or conventional helix gears, is to use helix gears with a reduced meshing angle of the helix gears.

I am old and I drive slow. This might be a solution too! That or shift from 1st to 3rd at say 4k rpm.

Thanks Mr. Ionbeam for the insights.

I always feel like I should get PDHs in Physics after reviewing Alan's posts.

If the software change is to prevent over-revving in neutral, then that's not much to do with shifting... as some get into it with their dealer, all we can do is ask more questions. It may be described in a TSB the dealer might be willling to share a peek at.

I'm just going to take a stab at the helical gears gave more surface contact, but to squeeze in 6 where there were once 5, one or more of the gears may have thinner castings. Hack's pic is of a 5 speed, gears are fairly wide, and judging from the one I have here (in a basket), along with Festus pics... I don't see how you'd break a 5 speed gear.

If you didn't see the pics from the grenaded one I posted a link to, fair warning, these aren't pretty....... essentially the gear broke, scored up the spline on the trans shaft (you can see the shift fork but gear is completely missing), shrapnel everywhere, then a broken piece of gear ground against the crank, forced up into the piston, jammed it such that the connecting rod broke clean in two places, last pic is the middle section of the con rod. Fugly, but only one we know of that actually grenaded the engine. The other guy just had his tranny jam and stall out the engine.

...merely a flesh wound

First order of parts have arrived.
I believe Gypsy got his call today.


Canadian FJR

Received my official letter from Yamaha today.


Canadian FJR

Canadian FJR wrote: ↑Wed Dec 23, 2020 6:09 pm Received my official letter from Yamaha today.


Canadian FJR

Are you getting it done now or waiting until Spring? Taking it to Shore Cycle??

Shore Cycle, hopefully in January.
Fairing is all stripped off and everything is clean.

All ready for surgery.

Canadian

I have obtained from another sandbox, two PDF documents related to the recall. Describes how/what is to be done.....
Korean document is a pictorial description with brief words in a few languages. Canadian document is slightly different, more English description of the operations.
If anyone wants either or both of these, PM me your email and I'll get them off to you.

80,000 kms. Should I get the CCT replaced while things are apart? I haven't heard of any issues with the new tensioners.



Canadian FJR

Canadian FJR wrote: ↑Mon Jan 04, 2021 1:49 pm 80,000 kms. Should I get the CCT replaced while things are apart? I haven't heard of any issues with the new tensioners.



Canadian FJR

I don't think I would bother. No history of problems since 2008.

USA recall announced.

https://www.nhtsa.gov/vehicle/2016/YAMA ... 00#recalls

rbentnail wrote: ↑Tue Jan 05, 2021 5:36 pm USA recall announced.

https://www.nhtsa.gov/vehicle/2016/YAMA ... 00#recalls

Additionally, this is early in the recall, VIN's may not yet be fully populated...... I'd check in a coupla weeks.
link to Yamaha recall VIN lookup for any Yamaha recall..........
https://www.yamaha-dealers.com/public/w ... tions.html
Asphalt & Rubber article..... says recall not into effect until Jan. 13, 2021
https://www.asphaltandrubber.com/recall ... ar-recall/