Shaving the head

Hey All,

I am rebuilding my 650R. I looked at the head after I pulled it apart. The siloette that the gasket makes on the head leaves a lot of unused area. Would it be wise to grind the head down and smooth it so that it goes to the extent of the gasket? Please help me I have my grinder ready? Thanks

P.s sI know that this would lower the compression ratio but I am going to bore the cylinder out to 102.4 and put in a 11:1 piston in it. Thanks for the help.

I'm guessing your talking about opening up the combustion chamber... :)

You may screw up the flow charteristics designed into the head and possibly the flame travel and so on...I'd recommend against it unless you have a flow bench and a couple of heads to play with to find the best set up TMO.. :)

DUDE! Put the grinder down and step away from the engine! :):D

Clean it up using only a soft gasget scaraper as needed, do not grind ANYTHING. The fact that you have to ask this question means you do not have the expertise to embark on modifing your head.

I have rebuilt two 650R engines from complete teardown, it should go together easy. :)

I do not know what you mean, warped??? Or matching the head to the cylinder??

If the head is warped you need to have it surfaced. (straight edge will tell you) This will raise the compression (if you put in a 10.25:1 this may raise you compression to over 11:1) Then you can put in a thick gasket. I went high compression on a XR600R an wish I never did. An air cooled engine gets hot spots and can ping easier in warm weather. I would try and keep you compression to 10.25:1 or lower if you are not planning on using race gas or you can get 94 octane fuel.

I really liked that "Put the grinder down, hands where we can see them and step away from the engine!"

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