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valves lapped, valve seat width?

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valves lapped, valve seat width?


Old 09-01-2016, 11:24 AM
Weekend Warrior
Thread Starter
Join Date: Jan 2016
Posts: 2
Default valves lapped, valve seat width?

On my 04 Foreman 450s, I lapped the valves and measured the seat width. These measure over 2mm. The spec says 1.2-1.5mm. I see pictures online of new valves and my seat width looks similar to the factory seat width of new valves. I am wondering if there is an error in the factory manual.

I did not have any Prussian blue when I did these, but will get some today to check the fit.

So does anyone see any issues with my valves or seats?
Attached Thumbnails valves lapped, valve seat width?-valves.jpg  
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Old 09-02-2016, 03:10 AM
Extreme Pro Rider
Join Date: Oct 2013
Location: Lancaster England
Posts: 3,372

I wouldn't worry about it. In theory the valve seat should be fairly narrow, though wide enough to take the heat out of the valve when closed. So for maximum flow in high performance engines, seat width is important. The 450 Foreman isn't a truly high performance engine.
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Old 09-02-2016, 09:06 PM
Pro Rider
Join Date: Jun 2010
Location: Notheast Alabama
Posts: 1,377

Yeah I think values be fine yeah alittle wide but shouldnt be any issues on them sealing off an doing there job
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