Leaking cylinder head (pictures) - Ducati Monster Forums: Ducati Monster Motorcycle Forum

opwierde · 01-15-2006, 04:52 PM

I found my oil leak.... turns out it was a bit of a bigger problem

[img width=600 height=450]http://www.kilburn.nl/monsterblog/images/klep_koplek.jpg[/img]

[img width=600 height=450]http://www.kilburn.nl/monsterblog/images/lek_cylinder.jpg[/img]

You can see where the gasses have been blowing by. The surfaces feel really smooth and undamaged, could uneven tightening be the cause? What is the best way to fix this, a thin gasket? Or just clean and reassemble?

tia, Peter

ducman851 · 01-15-2006, 05:00 PM

As youve realized there is no head gasket on the air cooled bikes. Id clean the surfaces up really well, replace the orings and properly torque them upon installation.

I supposed a loose or fastenter that wasnt up to proper torque could have caused this, You may want to check the cylinder itself for flatness with a straightedge.

opwierde · 01-15-2006, 05:14 PM

Look again... it's water cooled

It's a ST2 engine, 2 valves, with a bit higher compression and 44cc more than a Monster 900 engine. I guess Ducati decided that it ran too hot for air cooling.
Thanks for the quick reply. The four head bolts were nice and tight (I had to hit them quite hard). I'll try to borrow a straightedge and check.

ducvet · 01-15-2006, 05:16 PM

be sure to lap the cylinder to the head also .
the 2valve liquid cooled bikes were prone to leaking above the exhaust port (like yours).
somwetimes just keeping the rea cleen is the best you can do.
good luck

ducman851 · 01-15-2006, 06:43 PM

[quote=opwierde ]
Look again... it's water cooled

mark.Aust. · 01-16-2006, 04:34 AM

Just want add my 2 cents worth, It is obviously not the first time the head was off. Around those 2 green O rings looks like the leak (are those O ring a genuine part) is the worst. Incorrect torque procedure could warp the head and the point about the O rings was if they were not genuine they could be a wisker bigger/smaller thus coursing this problem. As the other guys said put a staight edge on it. Then again the head is not that big it could be hard to pick up without good quality measuring gear, end it needs to be with in a few thou of an inch because it has no gasket.

That was a lot for 2 cents. Mark

ducman851 · 01-16-2006, 07:55 AM

Ya know I went back and looked at the parts fiche for the ST2 and still stand by what I said. They still have no gasket at the head other than the 4 orings.

opwierde · 01-16-2006, 04:29 PM

Thanks for all the good advice!
I'll check for straitness and lap the head to the cylinder. I'll have to remove the cylinder for that and replace the base gasket as well.... The whole engine has been disassembled at least once to my knowledge, a cracked engine case thanks to a broken engine bolt. The green O-rings are standard Ducati, at least they are at the moment. My replacement set is green as well.

Tornado-rider · 01-17-2006, 03:28 PM

How do you lap the head to the cylinder?

opwierde · 01-17-2006, 03:53 PM

I'll talk to my local Ducati specialist first to be sure but I expect to use grinding paste on the mating surfaces of head and cylinder and grind/rotate them untill I have an even surface all round. Sort of like grinding valves. If the irregularities are too deep for grinding paste then it will need machining first. I checked the cylinder head for straightness, no problem there.