Moto Guzzi Stelvio NTX Valve Adjustment Procedure

[biking sailor]

As for the first quote? It is over two and a half years old and like all observations is subject to revision and re-examination in the light of further events. Problem?

Pete

Pete, those of us that do failure analysis for a living (I run the Quality Department for a material handling manufacturer and have certifications hanging on the wall showing I have passed testing to show proficiency in such) understand fully what you are doing and why in trying to figure out what is the root cause of the failures.  We appreciate your efforts and time you spend detailing your findings.  I'm following your posts even though I have no flat tappet big block, if for nothing else the opportunity to learn and be entertained.  Thanks, and keep up the good work!

Darren

"Only a fool closes his mind after only a few facts"

[sib]

Nice article.  Two brief comments:

1. You write:  "There are marks on the flywheel, as with all Guzzi models, to indicate when each piston is at TDC but they are not as obvious as on the older engines."  Not true for the newer V7 models.  None on my '13 V7 Stone, for example.

2.  You write:  "I like to dab a wee bit of anti-seize compound on the threads."  This is specifically discouraged by NGK for it's plugs, which have a zinc plating that acts as an anti seize.  Here's their quote:

Issue
Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug in the cylinder head; this stretches and fatigues the threads of the spark plugs, causing a much higher probability that the plug will break during installation or in some cases upon removal.
Solution
For spark plugs with special metal plating simply do not use anti-seize on initial installation; all NGK Spark Plugs are manufactured with a special trivalent zinc-chromate shell plating that is designed to prevent both corrosion and seizure to the cylinder head; thus eliminating the need for any thread compounds or lubricants.

[leafman60]

Nice article.  Two brief comments:

1. You write:  "There are marks on the flywheel, as with all Guzzi models, to indicate when each piston is at TDC but they are not as obvious as on the older engines."  Not true for the newer V7 models.  None on my '13 V7 Stone, for example.

2.  You write:  "I like to dab a wee bit of anti-seize compound on the threads."  This is specifically discouraged by NGK for it's plugs, which have a zinc plating that acts as an anti seize.  Here's their quote:

Issue
Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug in the cylinder head; this stretches and fatigues the threads of the spark plugs, causing a much higher probability that the plug will break during installation or in some cases upon removal.
Solution
For spark plugs with special metal plating simply do not use anti-seize on initial installation; all NGK Spark Plugs are manufactured with a special trivalent zinc-chromate shell plating that is designed to prevent both corrosion and seizure to the cylinder head; thus eliminating the need for any thread compounds or lubricants.

Thanks SIB.

1. The subject of the 2.5 year old posting is a 1200 8V Stelvio. If the V7 has no flywheel marks, that's fine.  Good to make the note. Just use your soda straw as shown.

2. The plugs onto which I used the anti-seize are not new.

However, I also use a little on new plugs but I also am careful about not using excessive torque when tightening. I've never ever had a problem except occasionally with plugs that have not been wiped with a little anti-seize.

H-D also recommends this in their manuals.

Do whatever makes you happy.

[andrewdonald1]

BTW:  I did not see any marks on the flywheel of my 13 NTX.
It appears that its a raised hump section of the flywheel and you align it horizontally dissecting the observation hole in half - if that makes sense.

[rocker59]

The stamped "D" and "S" marks on my flywheels have always been sort of close, but not spot-on.

Easier for me to stick something down the spark plug hole as I'm rotating the engine.

[sib]

Strangely, even though the newer small block engines do not have TDC markings on the flywheel, the bell housing nevertheless has the inspection hole, as well as the rubber plug for the hole.  I suppose this is because the bell housing is the same casting as was used on older engines that did have the TDC flywheel markings.  Or, perhaps, in Mandello del Lario, the flywheel department doesn't talk to the bell housing department.

[biking sailor]

My guess, based on my limited knowledge of MG and owning 3 of them, is that the factory just didn't put much attention to getting all the markings on them.   :BEER:

Such as no grease in bearing or splines, missing timing marks, half plastic fuel filters that split, engine mounting bolts not torqued/thread locked, ECUs not protected from rain, no fuses on aux lights, exhaust gaskets blowing out...

Just gotta get those little things sorted out from new, then ride the Guzzi's hard!   :bike

[Vasco DG]

On the newer bikes there isn't really any need for marks on the flywheel. Why they still bother with the inspection bung beats me? Why do you need it? Finding close to TDC is easy enough and to set the valve lash you only have to ensure that the followers are on the base circle of the cams, a few degrees either side isn't going to make any difference. As for ignition points these are controlled by the ECU based on input from the phase sensor which is triggered by the 'Phonic Wheel' on the dummy-shaft or camshaft on the 2V models.

Any marks on the flywheel assembly and even the hole to look for them are nothing more than a quaint anachronism.

Pete

[sib]

On the newer bikes there isn't really any need for marks on the flywheel. Why they still bother with the inspection bung beats me? Why do you need it? Finding close to TDC is easy enough and to set the valve lash you only have to ensure that the followers are on the base circle of the cams, a few degrees either side isn't going to make any difference. As for ignition points these are controlled by the ECU based on input from the phase sensor which is triggered by the 'Phonic Wheel' on the dummy-shaft or camshaft on the 2V models.

Any marks on the flywheel assembly and even the hole to look for them are nothing more than a quaint anachronism.

Pete

Now that we have an explanation for the peep hole and the bung, can anyone explain why the clutch housing on the '13 V7 Stone also has a drain plug, complete with gasket?

[Vasco DG]

What? On the Stelvio/8V? It doesn't.

[Boulder Ed]

Just a quick comment for any Guzzi noobs like me.  I used the above procedure  yesterday to adjust valves at 3,400 miles on a 2013 Stelvio I purchased 6 weeks ago with 1,890 miles on it.  I'm used to doing BMW valves so it was a pleasant surprise to not have to be on my knees bending over to get to the valves to start with.  After not ever seeing any flywheel marks, I defaulted to a chopstick with a felt pin line at TDC drawn on it, so I could see it approaching TDC in each cylinder.  I rotated the wheel carefully in 6th gear by hand with the plugs out, which saved the hassle of removing the front cover.  Start to finish took less than 2 hours, but could probably be done in one hour next time. 

I found all valves loose, by quite a bit.  I set them one at a time without using the two matched feeler gage method.  It really would have made no difference from what I saw and they all held fine, when I rotated the motor before buttoning up. 

Now the really good news:  my bike was suffering from a number of minor streetability issues that made me think I may have to do a throttle body sync.  These included being rougher and stumbling at starting, rougher when running with a bit more vibration up to around 4,000 rpm then smoothing out.  It also started dying at the first stop sign a block from home as it warmed up.  It was a bit more difficult to shift smoothy, and had a couple almost flat spots around 2,800 and 3,300 rpm to pull past.    Basically it needed to be fully warmed up and to run above 4200 rpm to be happy. 

ALL OF THIS WENT AWAY after the valve adjustment.  Cold starts are smooth.  No dying at the first stop sign.  You can ride it around at 2500 rpm if you want without any stumbling even, and pull smoothly throughout the rpm range.  No real change in vibration levels between 3200rpm and 4500rpm as there had been previously.  Much smoother now at lower RPMs.   

I was beginning to think I had a throttle body sync to check on but now it idles smoothly, starts smoothly when stone cold, runs smoothly.. so I'll wait a while on checking the throttle bodies. 

So, I am learning how these bikes respond to proper tuning and just how sweet they are when tuned properly.  I love this bike.