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Moto Guzzi Metal Stone Tappet Adjustment
The beauty of the transverse (yeah -that's another argument) Moto Guzzi V-twin is the easy access to the cylinders for tappet adjustment. I remember watching my father adjust tappets on early model Holdens but, otherwise, I'm self taught. But I wouldn't have had the nerve without the help of Big Daddy. If that little four year-old can do it, so can you! The tappets should be checked every 10,000km. These pics were taken prior to our 3000+km return trip to Coffs Harbour, NSW.
 | Start by removing the rocker covers. A 5mm T-bar Allen key makes the job much easier. I ordered mine online from the Snap-On site. |
 | Remove the spark-plug. You'll have difficulty fighting the engine compression if you don't. |
 | The gasket has come off, undamaged, with the rocker cover. You may have to give the cover a tap with a rubber mallet or piece of softwood. Note how clean the inside is. When I first removed the covers 20,000km ago, the inside was coated with white smegma which, I'm told, is caused by the engine doing short trips and not heating up the oil enough to remove condensation. The dealer used Motul. Well, my Guzzi doesn't do short trips. It does long trips at highway speeds. The shortest trip it does is 35km. I've switched over to Penrite Diesel 20w-60, much beloved by Harley drivers, and the problem has stopped. (The orange discolouration around the screw holes is from the copper-eze which helps prevent the threads binding - more on this later). |
 | Remove the rubber plug from the flywheel housing so you can see the teeth on the flywheel. |
 | Remove the cover from the alternator and using a suitable socket or ring spanner, rotate the alternator clockwise (as we're looking at it now). |
 | This what you're looking for. The 'D' is the timing mark for the right-hand side [from Latin for dextrous - a right-handed person] and the 'S' is the mark for the left-hand side [from sinister - a left-handed person. We're not allowed to burn them at the stake anymore]. These can be hard to see so you might need a torch or turn the bike so sunlight enters the hole. Note the notch on the right side of the hole for alignment. Turn the alternator until the cylinder is on the compression stroke. If you're like me, you'll probably have to rotate it several times until you're satisfied. Place your thumb over the spark-plug hole and you'll quickly determine if the piston is compressing! It's very obvious. Or place a straw in the spark-plug hole and watch it rise and fall to top-dead centre. |
 | This is NOT a timing mark. Guess how I figured that out! I wasted some time trying to understand why the tappets weren't playing the game |
 | When you're on the right stroke, both rockers will be open. Check for .10mm on the inlet side and .15mm on the outlet side. I look for a tight fit on the feeler blade. I've checked mine three times now and they haven't needed adjustment. |
 | Give the gasket and cylinder head a wipe. Just as my Dad taught me, I run a THIN smear of grease on the gasket, barely discernible, and place the cover back on the cylinder head. |
 | Prior to replacing the screws and the spark-plugs I put a thin coat of copper-eze on them. This will make them easier to undo next time. Replace the bolts. Everyone has a different technique for doing them up. I work a cross-wise pattern initially, then around sequentially. The aim is to tighten them all in an even manner so as not to warp the rocker cover and cause a leak. |
 | I've reused the same gaskets now for three checks. But buy a couple of spares before you commence work |
Mackerz |
Latest page update: made by Mackerz
, Jun 17 2009, 3:19 AM EDT
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Keyword tags:
Adjustment
Metal Stone
Moto Guzzi
Tappet
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| Started By | Thread Subject | Replies | Last Post | ||
|---|---|---|---|---|---|
| MichaelPergiel | Friendly tappet noise. | 0 | May 28 2009, 1:04 PM EDT by MichaelPergiel | ||
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Thread started: May 28 2009, 1:04 PM EDT
Watch
As I learn this bike I will learn to distinguish the tappet noise from the rest of the mechanical whirrings.
A little tappet noise indicates valve are fully closing and not burning. That is a good thing. Valves (especially on air cooled engines) that are mechanically quiet are not necessarily healthy. Apparently there may be a model year change from manual to non-adjustable tappets, but it will have to wait for me to open the valve cover to determine that. I would not be surprised that there is no change, considering how inaccurate/incomplete most published press is. |
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