This article was originally printed in the Moto Guzzi National Owners Club monthly newsletter. http://www.mgnoc.com
Admittedly, the V-twin Moto Guzzi is built like a Sherman tank; however, it does require periodic maintenance to keep it in proper order. One item that is definitely worth looking at from time to time is the drive shaft and universal joint. I tend to perform this maintenance about every 10,000 miles or three years, whichever comes first.
For those that have never performed this maintenance, it isn't that tough, just dirty and takes four to six hours depending on the individual and how many luggage racks need to be removed.
For the sake of safety, one should raise the rear wheel off the ground and support the bike under the engine pan. If you have a cycle lift, that is better yet. I have done it several times by using the center stand and a couple of ratcheting tie-down straps widely attached between the rafters of the garage and the rear frame of the bike frame. I use the straps simply for the extra stability and have never had the bike shift or wobble from the center stand.
Essentially you will need to remove the mufflers, loosen the rear axle pinch bolts, loosen the swing arm pivot nuts, remove the rear brake caliper, and lift the bike to remove the rear tire. Then proceed by removing the rear drive housing and the swing-arm. I normally drain the rear drive so as to avoid making a bigger mess than I already have. The touring bikes with all of their associated luggage racks can be a real pain, especially when trying to get the bolts back in place. I like to have a tapered punch to line up all the parts prior to starting the bolts. Since the shock absorbers have to come off to remove the swing-arm, you will have to remove any luggage racks.
[Ed Note: For years I've removed the rear wheel by placing a 2x4 under one leg of the center stand, and by tilting the bike over, put another 2x4 under the second leg and then again put a second 2x4 under the two legs. First by using a bungee cord or heavy duty rubber band I activate the front brake lever. This works great. If you don't have a center stand, I'm sorry. I can do this by myself, without help, but it's best if a second person helps. -FW]
Various models of bikes have features which make the procedure slightly different on different bikes. On older bikes, one can generally get on the swing-arm nuts with a wrench; however, on the California III and newer bikes, one has better luck with a socket.
In any case, in order to inspect the u-joint properly, one must remove the swing-arm. My experience has been that in order to get the swing-arm out, it requires removing the two large frame bolts located directly below and to the rear of the swing-arm pivot point. Every time I do this, I get a little leery because these bolts support the rear of the frame cradle, which is also attached to the center-stand. The bike always settles a bit, but I have never had any stability problems and that is why I use widely separated support straps from above the bike.
Once you get everything out of the frame, you will need to remove the carrier bearing snap-ring and press the carrier bearing and u-joint out of the swing-arm. My experience has been that the u-joint normally falls out of the carrier bearing if it has many miles on it.
The big killer on all for these parts is rust. It does little good to just grease everything and slap it back together. You must clean all the external (male) splines with a wire-wheel to remove the rust. I generally clean the internal (female) splines with a brass or copper 12-gauge shotgun "bore brush". Also, don't forget to clean the big spline inside the rear wheel hub and use a small wire brush to clean off the transmission output shaft.
I generally use this opportunity to repaint the swing arm and I always remove the swing-arm seals and bearings for a good cleaning and re-greasing. One may want to have some spare seals on-hand for the job. If you do this every three years, you will likely never have to replace the pivot bearings. At reassembly, I always replace the carrier bearing which is generally less than $30. I figure it is cheap insurance and I keep the old one in my tool kit for the road.
To properly reassemble, you will need both standard bearing grease and "anti-seize" grease containing "moly". The standard grease is used in the swing-arm bearings; the anti-seize is used on all the splines. The splines on the drive shaft are subject to enormous pressure and require grease that can handle the duty. Using standard petroleum grease will simply be thrown off by the rotational forces and extreme pressure. The moly will hang in there for years and has a dry lubricant that is similar to graphite, only the moly handles "pressure" much better.
The Guzzi u-joint is a pretty tough hombre but it should move smoothly on every axis and be free of any play. I generally anchor one end in a vise and twist on it with large water pump pliers. If you observe any free play, it's toast, get a new one. The same applies to roughness in the joint, get a new one.
The proper way to place the carrier bearing into the swing arm is to press it in with an arbor press;, however, I have also used a long brass punch to slowly tap it in from side to side. While I have been successful with this method, one can damage the bearing so be careful. Once the bearing is in place, reinstall the large retaining snap ring. Guzzi makes a special tool to properly insert the u-joint into the carrier bearing and it can be rented from Moto International for a reasonable price. The proper way to reinsert the u-joint into the carrier is again to press it in with an arbor press. I have also had good luck with an oak board and a dead-blow mallet. Again, this can damage the bearing and u-joint, but, so far I haven't done that yet.
The u-joint is supposed to have an "interference fit" into the carrier bearing. However, most simply fall out when dissembled. There are several solutions to making the old u-joint fit tight again. One is to reverse the u-joint and have the larger diameter bearing purchase area (opposite end) machined to a "press fit" on a new bearing. A local machine shop can provide this service; however, this is time consuming, and there are cheaper and faster methods.
I generally use a center punch and peen a couple of rows of 8-10 indentations around the circumference of the carrier bearing purchase area on the u-joint. This method expands the circumference of the u-joint and makes for a "press fit". Once I get this done, I clean the bearing and the bearing purchase area with alcohol, let it dry, and press everything together with blue lock-tite. Then I let it set for 24 hours before applying engine power. Another similar method is to have the local machine shop put a light knurl on the bearing purchase area, and then press it together. This is generally less time consuming for the machinist because he isn't trying to fit the two parts. Once knurled, you can file it back if the fit is too tight. Generally speaking, the tighter the better.
One other method I have heard discussed is using "cold release" lock-tight. This requires a special lock-tite that only releases well below freezing. The parts are preheated in an oven to about 250 degrees Fahrenheit and pressed together with the special lock-tite. Once the stuff sets up, the only way to break it free is to put your swing arm in the deep freeze and whack the part with a mallet. (Sounds like over-kill to me, but if it works for you, go for it!)
Now that the worst is done, put some anti-seize on the u-joint internal splines and output shaft of the transmission. Put the rubber boot on the transmission with the clamps loose and reinsert the swing arm back into the frame. Once you get the swing arm pivots properly centered and locked down, use a grease gun and pump a whole bunch of grease into the swing arm boot and clamp it down. This serves two purposes, it makes a moisture barrier for the needle bearings in the u-joint and if the rubber boot splits, the grease will leak out on your garage floor informing you that the boot needs replacement. Incidentally, "Harpers" now carries a boot that can be replaced without removing the swing arm. Probably the same type as used on constant velocity u-joints found on the front end of many modern cars.
Now, just bolt every thing back up and make sure to put some moly on every spline including the wheel inner hub. Don't forget to refill the rear drive and you will be good for many years of service.
The tell-tail sign of an impending carrier-bearing problem is normally detected when it starts to chatter occasionally. This has an associated vibration in the floorboards when the bike is dead cold and moving slowly. Once the bike travels a block or so, the parts heat up and expand to fit properly and the chatter goes away. If you should ever experience this vibration at anything other than dead cold at low speed, the problem needs immediate attention. If the chatter goes away in a block or two when cold, the problem is looming, but is still serviceable. Since the u-joint is about $200 and the associated parts are probably more, it is well worth looking after. Not to mention how dangerous a shaft lock-up could be at 75 MPH.
Generally, a bike that gets a lot of use is less prone to having such problems. Bikes with very intermittent use are the best breeding grounds for rust formation on the driveline splines. Therefore, the three-year/10,000-mile limit should be strictly adhered to. I like to flush the brake system and forks at the same time, then I'm done for three years. Glory Be! Time to Ride!
The California Comfort Cruiser