12 tooth speedometer pinion?

[philwarner]

I received this notice yesterday that got me thinking about my 96 Cali's speedo gear again.

A topic you are watching has been removed by Antietam Classic Cycle.
Topic removed: wanted - 11 tooth speedo pinion for 96 Moto Guzzi Cali 1100

 Perhaps this was in the classified section?

  Anyhow, as an update I did finally receive my 11 tooth speedo gear set from India and installed the 11 tooth pinion in June of this year and now my speedo reads 10 MPH too high instead of 20 MPH too high.   Is there such a thing as a 12 tooth speedo pinion gear?  Or is 10 MPG too high the norm for this vintage of Cali speedometer?

[Antietam Classic Cycle]

Yes, it was in the Swap Meet section and was removed as part of my regular "culling" of older threads.

Has the rear drive been changed from the original 8/33 to an earlier 7/33?

[philwarner]

Yes, it was in the Swap Meet section and was removed as part of my regular "culling" of older threads.
Has the rear drive been changed from the original 8/33 to an earlier 7/33?

Yes it was changed to 7/33 by a previous owner twice removed along with de-coupling the brakes, adding a hydraulic clutch lever and chrome mud guards.  It is kind of a Franken-Guzzi.  The previous owner had a lower custom seat made.

 The speedo reads 10 MPH high with the 11 tooth and the tach reads 1000 RPM low....but I like it in spite of its foibles.

[Antietam Classic Cycle]

The 5-11 speedometer drive is the one used with the 7/33 gears, so it should be reading correctly. Did you change both pieces - the "worm" on the transmission shaft and the one that drives the cable?

[philwarner]

The 5-11 speedometer drive is the one used with the 7/33 gears, so it should be reading correctly. Did you change both pieces - the "worm" on the transmission shaft and the one that drives the cable?

I did not change the "worm" gear because looking up the gears for years with both ratios the worm gear had the same part number for 8/33 and 7/33 ratios.  I wondered about that, but so far the 11 tooth pinion seems to work OK with the worm gear already in my bike which I assume is the original that came with the 8/33 final drive.

California Special Sport parts catalog lists:
29 Bevel gear 8/33-----GU30354602
13 Odometer gear 5/10 (set)-----GU28762540
14 Gear (pinion)-----GU28763340
15 Chain ring Z11-----GU14766110

California 1100 Carb parts catalog lists:
29 Bevel gear 8/33-----30354600
31 Lay Shaft 5/11 (set)-----14762510
32 Pinion-----12763300
33 Ring gear-----14766110

California III 1000 parts catalog lists:
29 Bevel gear 7/33-----GU17354650
31 Gear Z5/11 (set)-----GU14762510
32 Pinion Z5 -----GU12763300
33 Chain ring Z11-----GU14766110

So the California Special Sport and 1100 Carb parts catalogs list the same “Chain ring” for 8/33 gearing as the California III 1000 parts catalog for 7/33 gearing, but a different pinion gear; 12763300 VS 28763340.  Might this be a 10 tooth pinion gear VS 11 tooth pinion gear and Guzzi designed the 10 tooth gear to fit the existing worm gear?

 I have read several comments from folks saying that the Guzzi Cali speedometer is optimistic, but is 10 MPH too high the norm?  I just remembered that the PO put new "sport" tires on my bike and I checked the size on it now in case that might be having an effect.  The manual says 140/80-17 and mine is a  140/80-17  69V.

[wirespokes]

Phil - the way to tell if the gearing is correct is whether the odometer is accurate. If it is, then the speedometer was calibrated to read optimistic.

Most people don't realize speedometers are actually two separate and individual gauges in one - odometer and speedometer. The odometer is dependent on gearing (revolutions per mile) and the speedometer depends on how rapidly the cable spins. Both gauges are driven by the cable (if mechanical) but that's about all they have in common.

[philwarner]

Phil - the way to tell if the gearing is correct is whether the odometer is accurate. If it is, then the speedometer was calibrated to read optimistic.

Most people don't realize speedometers are actually two separate and individual gauges in one - odometer and speedometer. The odometer is dependent on gearing (revolutions per mile) and the speedometer depends on how rapidly the cable spins. Both gauges are driven by the cable (if mechanical) but that's about all they have in common.

Thanks for your reply; I did not know that.  I assumed that if the speedo read high that the odometer also read high.  Can I assume the trip odo and the main odo will record the same number of miles?  I do have a speed/miles app on an old cell phone that I can use to check the miles against the trip odo, but I haven't done that since installing the 11 tooth pinion.  Maybe a good excuse to stop sweeping oak leaves and go for a ride today or tomorrow.

[wirespokes]

Thanks for your reply; I did not know that.  I assumed that if the speedo read high that the odometer also read high.  Can I assume the trip odo and the main odo will record the same number of miles?  I do have a speed/miles app on an old cell phone that I can use to check the miles against the trip odo, but I haven't done that since installing the 11 tooth pinion.  Maybe a good excuse to stop sweeping oak leaves and go for a ride today or tomorrow.

The trip meter is driven by the odometer 1:1. So it's got the same reading - just resettable. When you get down to the fine points, the odometer won't be completely exactly accurate. That's because the gearing is set up to be close enough. I'm more familiar with airhead gauges and that's what I've found - rarely do  they completely match the final drive revs/mile. And then you've got the tire circumference which can vary as well.

So don't be surprised if mileage is 1% or 2% off.

I'd wondered how Guzzi matched speedos to final drives and figured it must be a gearing change at the transmission. But I'd never run across that. BMW went the route of having a different speedo for every FD ratio. Kinda crazy, but hey - it gives me more work.

[philwarner]

The trip meter is driven by the odometer 1:1. So it's got the same reading - just resettable. When you get down to the fine points, the odometer won't be completely exactly accurate. That's because the gearing is set up to be close enough. I'm more familiar with airhead gauges and that's what I've found - rarely do  they completely match the final drive revs/mile. And then you've got the tire circumference which can vary as well.

So don't be surprised if mileage is 1% or 2% off.

I'd wondered how Guzzi matched speedos to final drives and figured it must be a gearing change at the transmission. But I'd never run across that. BMW went the route of having a different speedo for every FD ratio. Kinda crazy, but hey - it gives me more work.

OK, good to know trip and main odo should be the same; guess I could have checked that easily enough.  I'll try to do a miles comparison with the phone app tomorrow.

BTW, if you are still looking for an 11 tooth pinion, the one I bought on eBay for $41 seems to be working OK although I ordered the set just before the - hit and India was locked down for several months delaying delivery.  I used just the 11 tooth pinion gear and retained the original housing/bearing and "chain ring" gear.  I can send you my notes and measurements if you are interested.

[wirespokes]

I haven't been looking for a speedo drive gear change - as a matter of fact, I didn't even know how it was done until this thread popped up. So far, all of the Veglias I've messed with have had the same gearing (1600 revs/mile) so it wasn't a problem replacing or swapping speedo heads.

[philwarner]

I haven't been looking for a speedo drive gear change - as a matter of fact, I didn't even know how it was done until this thread popped up. So far, all of the Veglias I've messed with have had the same gearing (1600 revs/mile) so it wasn't a problem replacing or swapping speedo heads.

That was aimed at Antietam Classic Cycle, but I may have misunderstood that it was their search for one in the classifieds when they may have just been cleaning up the listings.

I took a ride today with the DigiHUD app on my wife's old Samsung Galaxy S4 cell phone running and at the end of the ride DigiHUD said I'd gone 34.31 miles and the Cali's trip Odometer said I'd gone 36.5 miles, so the Odometer is reading 6.4% too high.  That is better than the speedometer which reads 20% too high (shows 60 MPH when my GPS shows 50 MPH), but nowhere near the 1% to 2% error mentioned.

I verified that I have the 7 tooth final drive pinion with an inspection camera, so is it possible that I have something other than a 33 tooth ring gear?  Or is 6.4% close enough in Italian?

[wirespokes]

I've heard that the GPS mileage readings aren't calculated exactly. Maybe, maybe not. I don't know. But I think I'd try a straight section of road five or ten miles long. Maybe the difference on a test like that would be less. Or run the test over roads ridden regularly, but a longer distance - say 100 miles.

I don't know what's acceptable in guzziland but with the beemers 6 or 7% is 'next gearing up', 'or down', territory.

It gets a little complicated figuring out gearing changes - and the hardest part for me is deciding whether to go with more teeth or less. 

What gear is spec'd for the 7/33 Final Drive? That seems the most logical solution. Then, if the speed is still way off, re-calibrate the speedo.

[philwarner]

I don't know what's acceptable in guzziland but with the beemers 6 or 7% is 'next gearing up', 'or down', territory.

What gear is spec'd for the 7/33 Final Drive? That seems the most logical solution. Then, if the speed is still way off, re-calibrate the speedo.

I understood it was 11 tooth speedometer pinion for 7/33 and 10 tooth for 8/33 with the same speedometer ring gear.  7 to 8 on the drive pinion is a 15% increase in speed, but 11 to 10 is a 9% decrease speedometer cable revolutions.  Not sure how that works.

I don't find anything on the tube about how to calibrate a cable driven speedometer or odometer.  I suspect it might be possible with the speedometer perhaps with a tweak to a spring, but I assume the odometer is controlled by a set of gears that have a fixed relationship with the driving cable.

BTW, I have a little spark activated tachometer that reads higher than the OEM tachometer by about 1000 rpm until the engine gets up to 4000 RPM at which time the Guzzi tach needle catches up with the little digital tach display.  My bike does not like to pull a hill if below 2500 RPM on the digital tach (1000 indicated on the Guzzi tach), and it seems happiest at 3000 RPM and above, and this is with 7/33 gearing.  Does that sound like it is down on power? 

[jwinwi]

  My bike does not like to pull a hill if below 2500 RPM on the digital tach (1000 indicated on the Guzzi tach), and it seems happiest at 3000 RPM and above, and this is with 7/33 gearing.  Does that sound like it is down on power?
[/quote]

No. Don't ride it like a Hardley. Anything below 3,500 is lugging it. Power is made above 4,000.

[Wayne Orwig]

My bike does not like to pull a hill if below 2500 RPM on the digital tach (1000 indicated on the Guzzi tach), and it seems happiest at 3000 RPM and above, and this is with 7/33 gearing.  Does that sound like it is down on power?

Pretty normal IMHO.
I used to tow a camper a lot and my 2004 was great at it. It has a cam that provides lots of torque by around 2500 RPM. My 1994 California on the other hand did not have that grunt until well over 3000 RPM. The 7/33, as opposed to the stock 8/33, gets you to that higher RPM faster. But the 7/33 did drop my fuel economy a bit at high speeds.

[wirespokes]

Yes, the engines don't like to be worked below 3 or 3500. I'm guessing you've got a mechanical tach on the bike?

I need to get a picture of the speedo drive gears at the transmission end to totally understand, but I get the idea. As for calibrating a speedometer - if it's fairly close to original, then resetting the needle will get it close. What I mean by 'close' is it'll quite possibly be accurate at only one point of the dial. For example, you might set it to read 20 when actual speed is 20mph. From then on up, it might read just a little slower or faster. Maybe it'll read 29 instead of 30, 38 instead of 40, 47 instead of 50. Or the other way around. Getting them to read exactly from slow to fast can be difficult sometimes.

Mechanical speedos, and tachs, work off of a mechanism designed sometime around 1900. They all work the same way - a spinning magnet creates a force field that influences an aluminum cup surrounding it. The cup wants to spin right along with the magnet but is restrained by a coil spring. The faster the magnet spins, the stronger the force field and the farther the cup turns. The cup is mounted on a shaft and on the other end of that shaft is the needle.

The needle movement is a function of the force field versus spring tension. A lesser factor is friction and sticky or stiff lube.

When the gauge reads correctly at one speed but is way off at another, then the other factors need to be addressed, rather than a simple calibration involving re-positioning the needle on the shaft. Magnets and springs can get weaker, which will of course affect accuracy, but when bushings get sloppy, that can also cause issues.

For such a simple mechanism they sure can be a complex problem when they're not working right.

If your odo readings are six or seven percent high, the cable is making too many revolutions per mile.

 

[philwarner]

Yes, the engines don't like to be worked below 3 or 3500. I'm guessing you've got a mechanical tach on the bike?

I need to get a picture of the speedo drive gears at the transmission end to totally understand, but I get the idea. As for calibrating a speedometer - if it's fairly close to original, then resetting the needle will get it close. What I mean by 'close' is it'll quite possibly be accurate at only one point of the dial. For example, you might set it to read 20 when actual speed is 20mph. From then on up, it might read just a little slower or faster. Maybe it'll read 29 instead of 30, 38 instead of 40, 47 instead of 50. Or the other way around. Getting them to read exactly from slow to fast can be difficult sometimes.

Mechanical speedos, and tachs, work off of a mechanism designed sometime around 1900. They all work the same way - a spinning magnet creates a force field that influences an aluminum cup surrounding it. The cup wants to spin right along with the magnet but is restrained by a coil spring. The faster the magnet spins, the stronger the force field and the farther the cup turns. The cup is mounted on a shaft and on the other end of that shaft is the needle.

The needle movement is a function of the force field versus spring tension. A lesser factor is friction and sticky or stiff lube.

When the gauge reads correctly at one speed but is way off at another, then the other factors need to be addressed, rather than a simple calibration involving re-positioning the needle on the shaft. Magnets and springs can get weaker, which will of course affect accuracy, but when bushings get sloppy, that can also cause issues.

For such a simple mechanism they sure can be a complex problem when they're not working right.

If your odo readings are six or seven percent high, the cable is making too many revolutions per mile.

Thanks for the info.  I had not thought about the tachometer drive, but looking at the parts manual it says "29767240  Rev. counter electronic (Carburetor version)" and there is a different part number for the injection version.  So, it's not mechanical but electronic.

Now that I know that I should be running higher revs, the tach is closer to being correct at higher revs.  I was riding it more like my Triumph America which pulls from 2500 and rarely gets over 4500 on the two lanes I usually ride where 3000 RPM is 50 MPH in 5th gear. (conveniently, 3000 is also 40 in 4th and 30 in 3rd in case you forget which gear you are in.)

Here is a photo of the speedometer cable drive gears




So the speedometer needle can be moved CCW to read a bit lower?  Is it just a friction fit on it's shaft?  Is it something an average person might do without breaking it?  If so I may give it a shot so I don't have to keep reminding myself it is 10 MPH higher than my actual speed.  Other than reading too high it is fairly smooth in operation - no big jumps or wobbles as speed increases.

Apparently there's not much I can do about the odometer error, though, since it is now an 11 tooth pinion that is supposed to be correct for the 7/33 gearing and the rear tire is the correct size.

[philwarner]

Pretty normal IMHO.
I used to tow a camper a lot and my 2004 was great at it. It has a cam that provides lots of torque by around 2500 RPM. My 1994 California on the other hand did not have that grunt until well over 3000 RPM. The 7/33, as opposed to the stock 8/33, gets you to that higher RPM faster. But the 7/33 did drop my fuel economy a bit at high speeds.

Thanks, Wayne,

Should I expect to see the same 2500 RPM grunt from a 2003 EV Touring?  I've been trying to get up to KC to look at and ride a 2003 to see if I like it better than my 96, but a series of things got in the way including my Mini Cooper S blowing a belt tensioner and trashing its vibration damper on my first attempt to make the trip, and that was not a simple thing to fix on a Cooper.

[Wayne Orwig]

Thanks, Wayne,

Should I expect to see the same 2500 RPM grunt from a 2003 EV Touring?  I've been trying to get up to KC to look at and ride a 2003 to see if I like it better than my 96, but a series of things got in the way including my Mini Cooper S blowing a belt tensioner and trashing its vibration damper on my first attempt to make the trip, and that was not a simple thing to fix on a Cooper.

Yes the 2003 should have the hydraulic lifters and cam with the broad power band.

[wirespokes]

It's easy enough telling if the tach is cable driven or electronic. If there's no cable out the back then it's gotta be electronic.

Calibrating the speedo first involves removing, then replacing the bezel. That's a game in itself. Then the needle needs to be lifted straight up or the shaft can be bent. I've forgotten what's involved lifting them off but whatever you do, lift it straight up. Usually grasping the needle and pulling up isn't a good idea. They tend to be stuck on there pretty good. The shaft is tapered so it's a wedge/taper fit.

[philwarner]

Yes the 2003 should have the hydraulic lifters and cam with the broad power band.

OK, thanks Wayne,

Looks like a rainy week end in store here, but maybe I can get up there next week to take a ride if no more family and neighbor crises come up.  I'd not heard about the significant torque difference before and it sounds like the 03 might suit my old man riding style.  The recalls have been done on it and the owner says it has the two plate clutch, so it should be good to go.

[philwarner]

It's easy enough telling if the tach is cable driven or electronic. If there's no cable out the back then it's gotta be electronic.

Calibrating the speedo first involves removing, then replacing the bezel. That's a game in itself. Then the needle needs to be lifted straight up or the shaft can be bent. I've forgotten what's involved lifting them off but whatever you do, lift it straight up. Usually grasping the needle and pulling up isn't a good idea. They tend to be stuck on there pretty good. The shaft is tapered so it's a wedge/taper fit.

Yes the tach is a Veglia electronic tach;  I'll watch it at higher revs where it seems to be more in agreement with the spark driven tach before I decide if it is worth tinkering with it.  Good to know the speedometer needle is a taper fit if I decide to try adjusting it.

[Wayne Orwig]

So the speedometer needle can be moved CCW to read a bit lower?  Is it just a friction fit on it's shaft?  Is it something an average person might do without breaking it?  If so I may give it a shot so I don't have to keep reminding myself it is 10 MPH higher than my actual speed.  Other than reading too high it is fairly smooth in operation - no big jumps or wobbles as speed increases.

If you can get the bezel on and off, you can get the needle off. It is pressed on the shaft. Easily bent I suspect if you aren't careful. I have really thin needle nosed pliers that I can slip under it and pry it up evenly. Don't forget to mark the drum clearly for the 'zero' position, so you get it back to the spot you want.