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Joko
10/24/2016 7:34pm
10/24/2016 7:34pm
Anyone have any DIY tips for porting cylinder heads to get basic flow improvements without risking ruining the head? Maybe basic bowl blending without hitting the valve seats, excess casting removal, what shape and size carbide burr to use, what is a good inexpensive brand air gun-grinder to use?
Just Google diy porting. Endless info out there.
Short version: don't remove a lot of material. Port match if necessary, smooth out your short side radii, keep your intake finish smooth, but not polished. A slightly rough intake finish helps with atomization, Polish your exhaust side.
I use a snap-on burr set 1/4 ball tipped cylinder, 1/2 ball, 1/2 to 1/4 taper are my 3 favorite carbides. From there paper rolls, then red pads, then green pads, then buffing ball with compound for the polish.
The short side flow is the most important part. Just when the valve cracks open and shuts close.
I did my 15 crf450 and it makes you feel good when the weakest bike pulls slowly past on a long start uphill straight against a new yam and Ktm!
If you absolutely must must fk with it, just blend the seats into the runners and stop there... majority of gains to be had are within 1 inch of the valve seat.
The Shop
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