Yamaha 200. Can I mill cyl heads?

[milljo]

A 1996 Yamaha 200 HP. A break in the head gasket allowed blowby gasses to erode some of the metal on the head. My question is: Can these heads be milled? and if so how much? It appears I only need about .5 mm to smooth the head. I can't find any milling specs in the manual. Any assistance is appreciated.

 

[rodbolt]

Re: Yamaha 200. Can I mill cyl heads?

hello<br /> I have taken as much as .020" off of them with no problems. try to take as little as possible to clean it up.

 

[milljo]

Re: Yamaha 200. Can I mill cyl heads?

Thanks Rodbolt. This should be a much less expensive solution than a new head.

 

[rodbolt]

Re: Yamaha 200. Can I mill cyl heads?

much cheaper. in fact about the best way I have found to flatten a head surface is with a 6 or 8 inch belt sander. its quicker and faster than setting it up on a mill. try to find a machine shop that has outboard experience.

 

[milljo]

Re: Yamaha 200. Can I mill cyl heads?

Success! a local machine shop shaved off .020 of head for only $28. Looks perfect. Some polishing with sandpaper and it is ready to go back on.

 

[Dhadley]

Re: Yamaha 200. Can I mill cyl heads?

Did you cut both or just the one?

 

[rodbolt]

Re: Yamaha 200. Can I mill cyl heads?

raven<br /> other than maybe some deburring around the combustion chamber it should be ready to go. if done properly it wont require any sanding on the head.and doing both will be reccomended.

 

[Ray Neudecker]

Re: Yamaha 200. Can I mill cyl heads?

You should not have a clearance problem with 20 thousands, but you should do both or the misbalance in compresion will result in a reduction of hole shot.