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Author Topic:   cylinder head clean-up
Dirt Maniac

Total posts: 114
posted October 22, 2005 09:13 AM  
Which is better to backcut the valves or more angles on the seats. We have been running a untouched head and are now allowed to pocket port down to the valve guide. What will give the most improvement? Also how much will smoothing the ports make? Enough to tell on the track? BIGG C

Dirt Full Roller

Total posts: 65
posted October 23, 2005 10:33 PM  
doing any of what you mentioned will make a difference and you would see gains on the track.

Dirt Freak

Total posts: 217
posted October 24, 2005 08:24 AM  
go to standard abrasives web sight they have some good info to read.Don't smooth the intake ports,its best to have a little rough feeling on the intake,but polish the exhaust so supposedly the carbon won't stick to it.

Dirt Forum Racer

Total posts: 98
posted October 26, 2005 08:57 PM  
As far as porting - a pocket port job will yield the best gain with minimal effort. As Vissar says - the first 2" below the valve are the most important. Bowl hog & clean up. I'd stick to 45 deg seats - 30 deg seats are a lot of trouble for the minimal gain. Always back cut the valves - it's too easy & helps a bit. You can find between 20 to 50 HP depending on other variables. Good luck.

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