What's causing this ?

[MGrego]

Hi All,

I am in the process of installing the roller conversion kit (going well, thanks to Pete's outstanding instructions) on my 2012 8v Norge, when I noticed that one of the intake ports in the left hand cylinder head had quite a bit of blackish build-up.  The bike has less than 4,000 miles on it, so my concern is that this is not normal and that something is amiss.  The residue is sticky, somewhat varnish-like, and oily. Only one of the two intake valves on that side is affected.  I have tried to post a picture, but I'm not sure if it will show up since I have never tried to post a picture to anything before.

Will getting the valves properly adjusted, the bike properly mapped and tuned fix this, or is something else going on ?

Thank you for your advice -

[oldbike54]

 Valve guide ?

  Dusty

[lucian]

If it is only in one port it is likely the valve guide oil seal. I think at this point I would pull the heads and pull the valves, clean things up and replace all the oil seals on the guides. Also check that all the valves are seating tightly by putting a little soapy water on top of the valve and blowing compressed air in the port below the valve watching for bubbles on top around the seat. My 09 griso with 6000 miles on it had the same deposits on the left intake side and had some blow by on that inlet valve.I re lapped all eight valves and rechecked them with the soap test before re assembling. You could just do the side with the issue but while your right there with both cam boxes off it's a pretty short trip to do it now.

[JoeW]

it's most likely caused by crank case ventilation, the vapor is vented into the air filter housing and for what ever reason, most of the vapors are being drawn into that cylinder. Just my 2 pennies worth.

[guzzisteve]

Bike leans left on sidestand, oil in airbox lays in rear left corner of it. If you have oil in the drain tube and it's full, all airbox oil will go in left side at start up.

W/4K miles on it, most likely not guide seals. I think Joe nailed it.

[MGPilot]

It that were so, would he expect to see blue smoke on startup?

[canuguzzi]

Bike leans left on sidestand, oil in airbox lays in rear left corner of it. If you have oil in the drain tube and it's full, all airbox oil will go in left side at start up.

W/4K miles on it, most likely not guide seals. I think Joe nailed it.

I drain the tube after every ride regardless of how little might be in there. Does that iyo help mitigate this type of condition?

[RinkRat II]

 Did Guido possibly leave that valve seal on the bench??

 Paul B

[guzzisteve]

Seen em smoke at start up w/oil in airbox.   Draining that tube is important unless you leave the oil level down a bit, even half way on the stick.

[MGrego]

Thank you for your replies --  I am going to investigate each of these,  I'll keep you posted --

[lucian]

The image looks more like carbon from blow by during combustion than just cooked on oil, hence I would check the valve seating at least on that one,and you have to pull the head to do so, at that point you should change the guide seals weather they need it or not for what they costs. Also take a good look inside the throttle bodies because if you have excessive oil from  the air box you will likely have similar crud in the tb,s.  Maintaining the oil to the top fill mark on the dipstick will result in higher crankcase pressures and more oil in the air box. I run mine at two thirds capacity (on the dip stick) and never have oil in the drain tubes and the throttle bodies remain clean. I was surprised at how minimal the seat ring on the valve rims and seats were. and they were anything but smooth. I chose to re lap all of them to not only eliminate leakage, but also to improve with heat dissipation. It was also an opportunity to polish up the intake port surfaces a bit as they are pretty roughly cast and provide a good surface for crud to accumulate on.  Other than fumbling with the tiny valve keepers it was an easy undertaking and worth the effort. Best of luck. Dave

[oldbike54]

 Is there any chance you are running leaded avgas ?

  Dusty

[MGrego]

I just completed the right side roller conversion this evening and discovered identical "gunk" deposited on the right head intake port. On further and closer inspection, all 4 intake valves have this deposit -- the valves closest to the midline of the bike to a greater degree. The throttle bodies looked clean, no obvious oil or deposits that I could see.

This leads me to believe I'm seeing cooked on oil from the airbox. Surely there would not be defective oil seals or valve seating problems on all the intake valves ??

Additionally, the oil level is at the very top of the high mark on the dipstick. I was about to change the oil anyway, so I will maintain the level at 2/3 as you (Dave) suggested going forward.

Eventually I may remove the heads, polish up the ports, relap the valve seats as suggested, but I'm just going to let it ride for now --

Thanks again for your help --

[fotoguzzi]

Where is Roper on this?

Additionally, the oil level is at the very top of the high mark on the dipstick.

wisdom from this group is that every Guzzi motor runs better with the dipstick level at half way between the bottom and top mark.

[MGrego]

wisdom from this group is that every Guzzi motor runs better with the dipstick level at half way between the bottom and top mark.
[/quote]

Good advice and duly noted !