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Main Area => General GS500 Discussion => Topic started by: jacob_ns on January 31, 2012, 08:26:52 PM

Title: Exhaust valve colouring
Post by: jacob_ns on January 31, 2012, 08:26:52 PM
Just looking for some insight as to what might be causing the colouring of the below exhaust valves. The first one (the lean coloured one) is the right hand exhaust valve and the dark/rich coloured valve is the left hand cylinder. I checked the valve spacing and the R/H exhaust valve is 0.10mm (0.02mm above spec) and the L/H exhaust valve is 0.08mm. The R/H intake valve is 0.10mm and the L/H intake valve is less than 0.05mm (I don't have a feeler smaller than 0.05mm).

Just looking for any wisdom or insight.

(http://i.imgur.com/muR6S.jpg)

(http://i.imgur.com/43qUF.jpg)
Title: Re: Exhaust valve colouring
Post by: BaltimoreGS on January 31, 2012, 08:42:45 PM
Does the spark plug coloration match what you are seeing on the valves?

-Jessie
Title: Re: Exhaust valve colouring
Post by: J_Walker on January 31, 2012, 10:08:54 PM
THIS IS EXACTLY WHAT MINE LOOK LIKE TOO! :D and yes the sparkys do match up, well at lease mine do..

Same ones and everything! Hahah what year is your bike jacob?
Title: Re: Exhaust valve colouring
Post by: Kijona on February 01, 2012, 01:44:42 AM
You are seeing a variation in fuel mixture between the two cylinders, a rather extreme one at that, it appears. Carbs might need cleaning.
Title: Re: Exhaust valve colouring
Post by: jacob_ns on February 01, 2012, 09:36:34 AM
The carbs were cleaned last summer when I rebuilt them both and replaced all the gaskets. I'll have to take a look and see if maybe they're not jetted properly.