Valve guides and porting - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums
 
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post #1 of 8 (permalink) Old 06-30-2013, 06:37 PM Thread Starter
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Valve guides and porting

Is it common to leave the valve guides untouched when porting a head? I ask bc I had mine ported a little over a year ago and noticed they were not filed down. After seeing more and more ported heads I see most are filed. Just curious.

08 yfz450, 12.5:1 JE piston, S customs port&polish, Shorty DG bullet exhaust, Alba front bumper, Alba grab bar, AC nerfs, 15t front sprocket, Cam mod, zip tie mod, FCI w/pre, no lid, Sredrum 42.5 fcr, Parking brake blocked, and hopefully more to come!!
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post #2 of 8 (permalink) Old 07-01-2013, 12:53 PM
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heads that use shim and bucket style valve setups....like the the yfz setup.... dont have lateral forces from rocker arms wearing out guides.....

you can cut the guide down to port wall without any bad side effects.....

more porting info avail here:

Porting..Theory...Tools..Techniques

Venom/ VooDoo Headwork PORTING: +10% Power increase entire rpm band
$275 complete combustion chamber and port mods for carb models
$375 HVP epoxy work for Fuel Injected models
10 day turn around / jcziehl61@gmail.com
http://www.yfzcentral.com/forum/32-y...echniques.html


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post #3 of 8 (permalink) Old 07-01-2013, 01:33 PM Thread Starter
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I have read your thread multiple time mixxer and I learned a lot. Thanks. I just didnt know if it was common or likely to not grind them down.

08 yfz450, 12.5:1 JE piston, S customs port&polish, Shorty DG bullet exhaust, Alba front bumper, Alba grab bar, AC nerfs, 15t front sprocket, Cam mod, zip tie mod, FCI w/pre, no lid, Sredrum 42.5 fcr, Parking brake blocked, and hopefully more to come!!
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post #4 of 8 (permalink) Old 07-01-2013, 01:35 PM
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most of the heads i have had leave the valve guide uncut, I have yet to see any real advantage from cutting it down.

If everything seems like your in control, your not going fast enough
ITS A MMAD WORLD
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post #5 of 8 (permalink) Old 07-01-2013, 01:45 PM Thread Starter
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That's what I was thinking but just wanted to double check. One more question if you dont mind. I have burnt coolant in the exhaust ports of my head and the combustion chamber of the head. Is there an easy was to clean it out or should I worry about it.

08 yfz450, 12.5:1 JE piston, S customs port&polish, Shorty DG bullet exhaust, Alba front bumper, Alba grab bar, AC nerfs, 15t front sprocket, Cam mod, zip tie mod, FCI w/pre, no lid, Sredrum 42.5 fcr, Parking brake blocked, and hopefully more to come!!
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post #6 of 8 (permalink) Old 07-01-2013, 02:43 PM
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Quote:
Originally Posted by climb-101 View Post
most of the heads i have had leave the valve guide uncut, I have yet to see any real advantage from cutting it down.

on a yfz its pretty much a moot point anyways..... they dont have big guides or big guide bosses..... not much to even cut if you did....

and it wouldnt matter if you did cut the little bit, because the valves are small ...and they are all bucket actuated.....

Venom/ VooDoo Headwork PORTING: +10% Power increase entire rpm band
$275 complete combustion chamber and port mods for carb models
$375 HVP epoxy work for Fuel Injected models
10 day turn around / jcziehl61@gmail.com
http://www.yfzcentral.com/forum/32-y...echniques.html


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post #7 of 8 (permalink) Old 07-01-2013, 02:44 PM
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Quote:
Originally Posted by dbbyfz450 View Post
That's what I was thinking but just wanted to double check. One more question if you dont mind. I have burnt coolant in the exhaust ports of my head and the combustion chamber of the head. Is there an easy was to clean it out or should I worry about it.
shouldnt be a problem to leave it alone

Venom/ VooDoo Headwork PORTING: +10% Power increase entire rpm band
$275 complete combustion chamber and port mods for carb models
$375 HVP epoxy work for Fuel Injected models
10 day turn around / jcziehl61@gmail.com
http://www.yfzcentral.com/forum/32-y...echniques.html


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post #8 of 8 (permalink) Old 07-01-2013, 07:08 PM Thread Starter
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Ok thanks mixxer for the advice.

08 yfz450, 12.5:1 JE piston, S customs port&polish, Shorty DG bullet exhaust, Alba front bumper, Alba grab bar, AC nerfs, 15t front sprocket, Cam mod, zip tie mod, FCI w/pre, no lid, Sredrum 42.5 fcr, Parking brake blocked, and hopefully more to come!!
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