You would think as I approach 61 years old that I would have learned by now that short cuts are rarely shorter, but in a spirit of eternal optimism and impatience I continue to blunder around in the hope that I will find some simple way around the self imposed problems thus created, before finally accepting that it would be easier to do it the right way in the first place. The job was to fix a long standing problem with the front right tank fixing, which has been stripped since I got the bike back in '02. The short (13 year) term solution was to wire the bolt in place, because, as you will have noticed, Moto-Guzzi's solution to the provision of a fitting involved the welding of an M8 nut to each side of the steering head. In my infinite wisdom, I had assumed this was a blind fitting, and too shallow to Helicoil, and decided the only solution would be to grind off the old nut, and weld on a new one, involving getting the machine along to someone who could carry that out. It was Tonya (a man who never takes a short cut, because he's a quicker learner than I) who pointed out that the steering head was drilled through, behind the nut, so there was nothing to stop a rethread being done. A quick torch inspection proved it, and what I thought was the outer surface of the head, was actually the axle of the steering stem, quickly proven by watching it move with a twitch of the handlebars. Idiot.
So, here's the offending nut, smooth as a virgin's thigh, and the axle beyond:
If I'd been looking for a real shortcut, I'd have drilled and tapped it in situ, but the thought of all those drillings joining the ball bearings at the base means that's not a good idea, so I heaved a sigh, and removed the tank, headlamp, fairing and instrument binnacle, to expose the forks.
A bit of time can be saved by tying up the handlebars, rather than dismantling them:
And then you reach that thing of beauty, that masterpiece of Italian engineering, that piece of bent steel, also known as the top yoke:
With the front wheel, brake cable and speedo cable removed, support the forks and then undo the 2 nuts that retain the fork springs. You need a 36mm spanner or socket. They are under slight spring pressure, so make sure they don't fly off into your eye. Putting your knee on top of the front mudguard and pressing down relieves most of the spring pressure, and in the past I've fitted a small scissor jack between the lower yoke and the mudguard, on a couple of bits of wood, to relieve all the pressure. Then undo the 36mm nut on the steering stem, to release the top yoke. A couple of taps with a nylon faced hammer may be needed to free it.
Undo the steering stem top nut, also 36mm, and remove the support to drop the forks out, complete with the steering stem. Good time to plan working on the valves, as you'll never get better access...
You're now committed to doing it the wrong way. As I knew before I started, and later confirmed, getting the stem back in with the forks attached isn't impossible, but it's impossibly difficult, and despite learning that the last time I did it, I persuaded myself that I didn't have Tonya's fork leg removal and replacement tool to hand, and I'd somehow find a way of doing it that was better than the last time. The answer is, that you need to remove the fork legs from the yokes, and despite not having the tool, I found it remarkably easy. Undo the two pinch bolts in the lower yoke (17mm, M8) and give the fork legs a sharp tap with a nylon faced hammer and they just drop out from the lower yoke. I used the handle to the hammer to knock them down inside the shrouds, until they just drop out. Of course that wouldn't be so easy with the top yoke in place, so take it off first.
Easy job to tap for the M8 Helicoil, and fix the tank mount.
This is why trying to put the steering stem back with the forks attached is almost impossible. I had the axle in, and set up a jack to support the weight. The idea was to stick the lower balls in with grease, jack the stem into place without displacing the bearings, and then fit the top balls and race. It didn't work. No matter what you do with the jack, the stem won't go in straight, and when you try to centralise it, one or more balls will drop out, and you have to start all over again. I also tried assembling the top bearing first, but without being able to guide the heavy forks accurately enough, the bearings still get knocked out. Next time, I'll just do it the right way...
Reassembly of the loose steering stem is a breeze. I used JCB waterproof grease, because it's thick and sticky and waterproof, and a bag of 1/4" chrome steel, through hardened balls (you need 36, 18 top and bottom) from Simply Bearings, whose free delivery order on Sunday had the bearings with me Tuesday morning. Recommended.
Previously, in an attempt to avoid a repeat of the rusty mess the lower bearings had become, I had inadvisedly fitted stainless balls, knowing they weren't as hard, but thinking they would be well strong enough. This is why that isn't a good idea.
I lined the top race with grease, and fitted 18 of the 1/4" balls, then the top race, making sure it was well seated and well packed with grease.
Added more grease to the top cap, to provide something of a seal.
Same procedure for the lower race:
Gently feed the stem into the head, making sure to keep it central, and pressing down on the top bearing to keep it seated. Thread the stem through the top bearing, and retain it with the top nut. Check for free movement, then adjust the bearing. I tightened until it just started binding, then backed off about 1/4 turn, checking there was no rock or free play.
Slip the fork shrouds into place:
Gather up the headlamp, and the binnacle wiring, and position them in the right place below where the top yoke will fit, then take the top yoke, and fit it over the adjusting nut.
Push the fork legs, minus the springs, through the bottom yoke, and thread them through the rubber bungs in the shrouds, and up into the top yoke. You should use the special tool to draw them right in, but mine moved so easily, I just fitted the cap bolts, and drew them in with those. Sorry for the bad photo.
Fit the pinch bolts and tighten securely. Mine were fitted with the nuts at the front, but the parts diagram shown them with the nuts at the back, so I fitted them that way.
Next, remove the two cap bolts, fit the springs and refit the bolts, taking the pressure off with your knee againto relieve the spring pressure. This is one of the jobs people say is really difficult, but I've now done it several times with no problems, simply by taking the pressure off.
Then it's down to reassembly of all the bits you took off:
Note the clothes peg to prevent the speedo cable ring dropping into the headlamp (thanks Paul Friday)
I have some new tank rubbers from Guzzibits, so that should be the tank OK for a while.
If ever there was an example of how much work needs done for a tiny little job, this was it....
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