Driveline Slack

[SMDL]

Happy New Year, all!

 

With only a few months of Toronto winter left , I'm starting to think about getting my '03 Le Mans ready for spring. One issue that needs attending to seems like it might be related to excessive play in the driveline. When I bought the bike last year, I picked it up in Florida and rode it home to Toronto over a three day period. It was a fantastic ride, and I really enjoyed the bike, although I will make a few changes to the ergonomics this year. Now back to the issue at hand:

 

When I initially picked the bike up, it was beautiful to ride. With only 6500 miles on the clock, and with the TLC that forum member mik had showered on it since new, the bike really rode just like it was fresh from the showroom. However, one thing it was in need of was new tires, so I stopped in Georgia and had a new set of Pirelli Angel STs put on (great tires!). Unfortunately, shortly after leaving the dealership, I started noticing that it was very difficult to maintain smoothness in my riding, particularly in lower gears (I didn't notice this at all before the tire change). Normally, I would have turned back and had the dealer take a look at it again, but my travel schedule was so tight, and I had already spent almost the entire day there, so I just adjusted my riding style to short-shift and be REALLY smooth on the throttle for the rest of the ride. I got her home fine, but subsequent rides have proven that something is definitely very different than when I first rode the bike, and the jerkiness has really taken the enjoyment out of the ride.

 

What I am wondering is if there is some sort of adjustment that can be made in the driveline to minimize slack? Is there something that the dealer should have done when putting the rear wheel back on and that I could sort out now? I'm very new to Guzzis, and haven't worked on many shaft drive bikes, but am certainly willing to dig in and get my hands dirty in search of an answer.

 

As an aside, I know that many people have reported similar symptoms related to the poor fueling characteristics of these bikes, and I suppose there is an outside chance that this might be the case (no PCIII or MyECU). However, Mick had gone to such lengths to have the bike tuned very well, and it ran so flawlessly before the tire change, that I have my doubts.

 

Any thoughts would be greatly appreciated!

 

Cheers,

Shaun

[pete roper]

When the tyre was changed did the driveshaft get separated? Quite often it will, especially if the people performing the tyre change are unfamiliar with the Guzzi set up.

 

If it has become separated and then has just been stuck back together any-which-way there is a very good chance the driveshaft trunnions are misaligned and tghis will cuse problems.

 

Look on the drive shaft where it jins and you will see that on both front and back parts there are paint lines that should line up If they don't? there is the most likely source of your problem. Not having the trunnions aligned is also murder on both the splines and gears in both gearbox and bevelbox.

 

Pete

[jrt]

Agree with Pete.

But also, there is significant driveline snatch in the V11 and it is especially noticeable at low gear/rpm.

By all means, check the paint lines, but if they do line up, then you are probably ok and just need to shift at higher rpm with a smoother clutch actuation. The new tires may have just brought to your attention what you've been doing before.

[Baldini]

If it were me, I'd take it apart & just check everything is present & correct. As Pete says Guzzi isn't mainstream. The axle can be a bit of a pig to get in & out, which might lead to something going awry, there's a short spacer in there which could go astray ...check shaft alignment & just look over everything else, cos it sounds like something is amiss since it's been apart. Have you got a parts diagram?

 

KB

[SMDL]

Thanks for the great info.

 

JRT, agreed that there is a slight possibility that this is just the nature of the beast, and that I hadn't noticed previously, but I really don't think so. The change was just too obvious, and I am generally very perceptive when it comes to sensing mechanical issues.

 

Pete, I'm really not certain if the shaft was separated when the tire was changed. I observed for part of it, but not all, so didn't see everything that the guy did. This is a tire store attached to a Guzzi dealership, but I think that most of the Guzzi work the guy had done was on newer CARC Guzzis. There was another guy there that was very familiar with older Guzzis, and he did help with some of the work, but I don't think he was around when the rear wheel was going back on.

 

Looking at the manual that I have on disk, I can see what you mean about the yellow lines having to match up on the shaft. I'll plan to get out to the garage to take a look, but might leave it for a day or two as it is -10C today, and should be going up to +1C over the next couple of days. I also see reference to "taking care not to lose the shim" on the rear wheel, so am looking for a worried smilie now. This should do:

 

I'm going to go dig out my copy of Guzziology, as well, to see what I can learn there.

 

KB, I have the user and service manuals on a disk I received from MI, but it doesn't seem to have a parts manual. Is one of these available online?

 

The advice is very much appreciated. I'll likely plan to take everything apart back there to see what's what. Regardless, I'll keep everyone posted on what I find.

 

Cheers,

Shaun

[pete roper]

 

 

 

KB, I have the user and service manuals on a disk I received from MI, but it doesn't seem to have a parts manual. Is one of these available online?

 

 

Not a parts book but if you want an exploded pic of the bevelbox?

 

[SMDL]

Cheers, Pete. Very much appreciated!

 

Shaun

[SMDL]

Hi, folks.

 

Just wanted to provide an update. I went out the other day (after it warmed up a bit), and found that the paint marks on the shaft were properly in alignment. So, that simple explanation doesn't fit, in this case. Oh well, once I get a bit more time, I'll plan on digging in a bit further. When I know more, I'll report back.

 

Thanks again for all the good info!

 

Shaun

[docc]

I've had those same results from too much Grappa.

[savagehenry]

Something else to consider,

There is a set of rubber wedges in the rear wheel casting. These need to be cleaned and lubed as part of the tire change. The function of the "pucks" is to act as a shock absorber between the rear wheel and the drive line. The first time I had a rear tire change and the cush drive maintenence, I could not believe how much smoother my bike became as far as drive line snatch/jerking. If this wasn't done when the tires were done, I would definately do it/have it done. Maybe there is a charge for this on your bill to confirm it was done, or not???

That being said, these bikes do not suffer lightly the rider with an unsmooth throttle wrist. The first time I whacked my tailbone with the rear seat cowling was the moment I decided to smooth my technique, asap

[SMDL]

Something else to consider,

There is a set of rubber wedges in the rear wheel casting. These need to be cleaned and lubed as part of the tire change. The function of the "pucks" is to act as a shock absorber between the rear wheel and the drive line. The first time I had a rear tire change and the cush drive maintenence, I could not believe how much smoother my bike became as far as drive line snatch/jerking. If this wasn't done when the tires were done, I would definately do it/have it done. Maybe there is a charge for this on your bill to confirm it was done, or not???

That being said, these bikes do not suffer lightly the rider with an unsmooth throttle wrist. The first time I whacked my tailbone with the rear seat cowling was the moment I decided to smooth my technique, asap

 

Thanks, SH. I've done some research based upon your post and plan to have a look at this as soon as it warms up a bit. I might even drill some holes!

 

Cheers,

Shaun

[lemppari]

After changing the rear tire, I noticed that the rear end assembly has a lateral slack of several degrees i.e. it's possible to wind it a few degrees horizontally when fully tightened. So what I'm actually wondering about is the ring, part no #31. Is it flexible, allowing horizontal turning, or am I justifiably terrified?

[gstallons]

After changing the rear tire, I noticed that the rear end assembly has a lateral slack of several degrees i.e. it's possible to wind it a few degrees horizontally when fully tightened. So what I'm actually wondering about is the ring, part no #31. Is it flexible, allowing horizontal turning, or am I justifiably terrified?

 

 

 

Huh?

[docc]

After changing the rear tire, I noticed that the rear end assembly has a lateral slack of several degrees i.e. it's possible to wind it a few degrees horizontally when fully tightened. So what I'm actually wondering about is the ring, part no #31. Is it flexible, allowing horizontal turning, or am I justifiably terrified?

 

No horizontal play. Check the spacer between the wheel and rear drive. Nothing "flexible."

 

I do not see #31 on my diagrams. Where do you see this?

[Buzzard]

If everything proves to be correct and proper in the rear drive, here is something that affects throttle abruptness on the Guzzi. Try moving the throttle position sensor (TPS) just a bit. Mark where it is now, so it can be retuned to home under any circumstances. I found that turning mine just a tiny bit counter-clockwise (as viewed from above) worked miracles. I know about all the methods for adjusting the TPS, and have done so on my LeMans, but to be honest, it runs much better, and has better drivability, with the TPS advanced. If I recall, the voltmeter shows 750mv at closed throttle with the setting I now use. This drivability includes the letting out of the clutch, shifting and throttling into the next gear, and rolling on and off the throttle. It's an easy adjustment to make, takes a few minutes to do. As I said at the beginning, if it does nothing for your bike, return it to home, and try something else.