1200 Sport 4V - Valve Inspection / Adjuster Wear

[Seweryn]

I have just completed the valve clearance and observed the same issue:  the same 6 valves needed minor or no correction and both inlet valves of the left cylinder required to be tightened by about a 1/4 turn.  It happens every time since I am the owner (bought it with 96k km on the clock, now it has 30k km more).  You can see the inlet valve adjuster screws sitting deeper than the other two.
Why do the (only) two adjuster screws wear out much quicker than the rest?  Should I replace them with new adjusters at the next service or leave them alone?

On the other hand I am quite happy with how the spark plugs look - they are dry and clean, although they have about 27k km on them (should be changed as per the manual).  Do you always change them every 20k km?  Secondly, is there anyone using iridium plugs instead of platinum?  When I bough the bike the previous owner had the iridium NGK just fitted, which I replaced with the factory standard platinum plugs.

[guzzisteve]

Seems normal for higher mileage 8V. One of the adjusters is no longer available, can't remember which thread though. Something I picked up reading on the Ghetto. Check your part #'s for availability from your importer.
I would make sure the threads have not run out under rocker. You need pressure on all threads for it not to fail.
Inspect the worn area's, if you have a small disc, curved on one side. A few parts that wear before it hits the roller. Check bushes in rocker for the pin.
Happy Wrenching

[faffi]

There are three things that can cause increased clearance in my limited experience; wear on top of the valve stem, wear on the adjuster or wear in the cam lobe. Or, very unlikely these days, lots of deposits on the valve.

[Seweryn]

There are three things that can cause increased clearance in my limited experience; wear on top of the valve stem, wear on the adjuster or wear in the cam lobe. Or, very unlikely these days, lots of deposits on the valve.

Sure, that is my experience too.  The question is why there is a noticable wear on two inlet valve adjusters on the left cylinder only?

[Chuck in Indiana]

Roper sez:

It’s not his adjusters that are the issue he’s either got a scrubbed cam lobe or a collapsing roller tappet and needs to pull his cambox several thousand Km ago!

Can someone get him to email me or contact me through the ghetto.

Thanks.

Or, PM me and I'll get you his email address.

[faffi]

Could be any number of issues, from a soft cam to a poorly hardened valve stem. You can eliminate (or pinpoint) the cam from the suspects by measuring valve lift and compare that to the number from the opposite cylinder. Not familiar with the design of that engine, but if it has short pushrods those can also be wearing, but should not affect lift.

[luthier]

Check your PM's mate.