New Owner XB9S - Is the transmission supposed to be bad?

[ItBit]

Picked up a 2003 XB9S a couple weeks ago and really like the bike aside from a few small issues.



The transmission shifts smoothly at low speeds, but at high RPM (specifically at the 1-2 shift) it's very noticeable how much the transmission does not want to change gears. I can feel and hear the teeth of the dog clutches bouncing off each other several times before it goes into gear.

On top of that, the engine doesn't seem to slow very quickly. It rev hangs, so re-engaging the clutch after a spirited gear change requires a delicate hand to avoid upsetting the balance of the bike.

For a motorcycle otherwise setup for serious performance, these seem to be glaring issues. They don't just make the shifts slower, they have made me reluctant to actually rev the bike out. Which is no fun.

Does anyone else experience this? Does it just come with the territory?

I feel like the engine's rev-hang is the root cause. Add in a little clutch drag preventing the input shaft from slowing down, and it's no wonder the transmission doesn't want to shift. Maybe if I could find an ECM tune to increase the engine braking at high RPM it would make things work more smoothly, but that seems like a stretch.

 

[rb70383]

Nice bike! Never had issues with my tranny doing that. The rev hang is an issue? There are some things that need to be checked first. I know I wont get all of them and the more brainy peeps will be along soon. Since you don't know the condition of the bike you need to see how mechanically sound it is. You could have leaking intake gaskets, which is a thing for these. Start with the basics on the tranny. Hows the fluid, clutch adjustment, cable?

 

[Cooter]

Yes there is a de-cel fuel cut setting to have the engine decelerate faster, and it can also be tuned with the fuel map. Buelltooth.com

These trans aren't the slickest out there (by far), but it should clunk into gear pretty easily at any RPM. Is the clutch disengaging completely (Does it want to creep forward in gear/clutch in/stopped?)

Since you are shifting at higher RPM, try to release some throttle pressure while still accelerating (don't chop it) and upshift without the clutch.

Or

https://www.buellxb.com/forum/showthread.php?56084-I-bought-a-quickshifter&highlight=quickshifter

https://www.buellxb.com/forum/showt...-and-1125-Quickshifter-install-CHEAP-and-EASY!

 

[Cooter]

Don't forget you're riding an almost 20 year old bike very very hard.

Go ahead and do it. But know that^^^^

 

[34nineteen]

I can feel and hear the teeth of the dog clutches bouncing off each other several times before it goes into gear.

If this is what is actually happening, then you've already called out the problem. I've never heard them called "dog clutches" as they are either one thing or another. Its like calling something a "wheel tire". Clutches are designed to slip. Gear dogs are either engaged or disengaged. If a dog slips, you need a rebuild.

Rev hang can be caused by a TPS out of sync, air intake leak, etc.

You also need to remember the bike has a long stroke, with heavy flywheels, compared to other non-Harley based bikes. Thats also going to create the slow deceleration... because physics.

 

[ItBit]

Thanks for the all the replies, guys! I went out to check over the items you recommended:

• Cable slack was right in the middle of the specified range
• Transmission fluid level just kissed the bottom of the clutch basket like in the diagram
• I was able to get 1 turn out of the adjustment screw under the clutch inspection cover, which I think decreases the gap between the clutch the actuator and the diaphragm spring. I figure that will help get a cleaner clutch disengagement.

I took it for a test ride to feel things out. I made sure to pull the clutch lever all the way to the bar and shift firmly, which seemed to help. I only noticed a little clatter on one of the 1-2 shifts I did.

When I got back I used brake cleaner to test for intake leaks, but didn't find anything. Honestly, I think I over stated things by saying "rev-hang", the bike just doesn't de-cel as quickly as I'd like. Good to hear that can be adjusted with a tune.

These trans aren't the slickest out there (by far), but it should clunk into gear pretty easily at any RPM. Is the clutch disengaging completely (Does it want to creep forward in gear/clutch in/stopped?)

Since you are shifting at higher RPM, try to release some throttle pressure while still accelerating (don't chop it) and upshift without the clutch.

I haven't noticed any creep while in gear at a stop. If there is power leaking through, I imagine it has to do with viscous friction between the clutch plates. Again, it seems totally fine unless I'm trying to have fun getting to 2nd gear.

I've tried a few clutchless shifts, but the engine mass and de-cel make for a brutal lurch.

Don't forget you're riding an almost 20 year old bike very very hard.

This is actually the newest bike I've owned! I had a '97 VFR750 and still have an '89 Radian 600. The VFR was butter smooth and really liked to shift without the clutch at any speed. The Radian, which is now going on 31 years of age, has taken a lot of abuse but still keeps on going. It shifts smoothly, and the only problem I get is popping out of 2nd if I don't move the lever all the way.

At the end of the day I'm probably just being too picky. Like 34nineteen said, it's a big heavy motor. And the 2nd gear dogs may be slightly damaged, but who knows.

I'm definitely going to look more into the Buelltooth and ECMspy websites. They seem like great resources. I'm amazed by how far the Buell community has gone to collect/share information and even make products to improve the bikes.

 

[34nineteen]

Like 34nineteen said, it's a big heavy motor. And the 2nd gear dogs may be slightly damaged, but who knows

Compared to those bikes, this bike is not going to have anywhere near the shift quality. In 2006? Buell made a change to the gearbox to help improve shifting quality, and even then, even a VFR with a trashed transmission will be smoother shifting.

Bear in mind that every time someone takes off from the line, they are going to do the 1-2 shift, and usually thats when the takeoff forces are the highest so, its not unusual for any transmission to have wear there.

Unfortunately, to get to the transmission gears and assembly, it ALL has to come apart. Not kidding.

Mentos or syrup in the primary case will not help. Unless you are Cooter.

 

[34nineteen]

'97 VFR750

This is a SWEET bike. I have no experience with the Radian.

 

[Cooter]

You told me to put the Mentos in the gas tank? Did I do it wrong? Its still foaming

"I've tried a few clutchless shifts, but the engine mass and de-cel make for a brutal lurch." The lurch is the same reason its skipping the dogs (besides the very valid 34:19 points). Ya, it's probably worn, and ya, the 1-2 shift is the most commonly beat up and the highest ratio change... but if you can get the MPH and RPM to match up well clutchless shifting, it will show you how to seamlessly shift even a worn trans.
Pull in the clutch, and give it half a beat before shifting?

 

[ItBit]

This is a SWEET bike. I have no experience with the Radian.

I really miss the VFR, and did not part with it willingly. The Radian was my first bike. It's nimble, low, soft, and not very powerful. Fun for a trip to the corner store, but not so much on the highway or in a canyon.

The lurch is the same reason its skipping the dogs (...) if you can get the MPH and RPM to match up well clutchless shifting, it will show you how to seamlessly shift even a worn trans.

That's part of my conclusion as well. After more time in the saddle I've adjusted my riding to cut the throttle earlier, wait a fraction of a second, then start the shift (with the clutch) so the drivetrain has more time to unload and that has helped. I'm not happy with the extra time it takes to shift, but it is smoother. I'm not a stranger to clutchless shifting, nor doing so on a worn transmission (my Radian for example), but this bike doesn't love it.

After riding for about an hour on a warmer day, I noticed even slower engine de-cel, especially at low RPM. This seems like the classic sign of a vacuum leak. I was too hot and sweaty to break out the tools to remove the engine shrouds and re-perform the brake cleaner test, but I did take a video of the bike running in neutral.

Does this seem like symptoms of a vacuum leak to you?



If it's not too difficult or expensive, I may just replace the intake gaskets as preventative maintenance at this point.

 

[Cooter]

Hmmm. It does seem to hang at 2k. Not that you're shifting there... but if you tested for leaks, maybe look in to the tuning?

It's rare I suggest that for a decent running bike. You could start with the ECM parameters that are easy to change (and change back) before committing to a whole fuel map.

Buelltooth.com

 

[ItBit]

Got back from a ride today and decided to try the brake cleaner test while the bike was still thoroughly hot.

This time when I sprayed the brake cleaner the engine speed would drop from 1000 down to 600 for a second or two then go back up. That's enough proof for me to believe there is an intake leak.

I've got a set of those thicker aftermarket gaskets from James Gaskets on order. Figure I'll change the oil while I'm at it for a fresh start.