One dirty valve

[George S]

I have a 2004 s4r and I recently noticed, while looking down through the throttle bodies, that only ONE of my valves has black, tarry looking build-up. It is the intake valve on the right side of the bike, on the rear cylinder. Like I said, the other three intake valves are perfectly clean and shiny.

What could cause this? how can this problem be remedied?


Thanks,
george

[ducpainter]

Are you running high test? That is the most common cause of carbon build up. Not sure why it would only affect that one valve.

Try some Chevron techron, or OMC carbon cleaner mixed in the fuel, and run 87 octane.

[Howie]

Tarry looking is probably oil coming through the guide.  If the bike runs well just  .  Most engines have some oil deposits on the back of the valve.  Techron will clean this up, just watch the ratio, better too weak than too strong.  If your bike doesn't ping on 87 run 87.

[George S]

thanks. I'll try running fuel additive and lower octane gas. any recommendations on additives? what about this sea foam stuff? I'm sceptical because the manufacturer will have you believe that stuff will fix ANYTHING! Sounds fishy to me.

[HotIce]

Seafoam, alone, brought back to life a motorcycle which would have otherwise to undergo to full carb (4 of them!) disassembly and cleaning.
I am not sure how well it also remove carbon deposits, as that was not my case.
But for me, it got me at "hello" 

[Howie]

Seafoam is real good for cleaning gum and varnish for gasoline.  I don't know how well it will work for carbon.  Techron works wonders with carbon.  Agian, be conservative on ratio. 

[Curmudgeon]

thanks. I'll try running fuel additive and lower octane gas. any recommendations on additives? what about this sea foam stuff? I'm sceptical because the manufacturer will have you believe that stuff will fix ANYTHING! Sounds fishy to me.

This is what dealerships and auto repair shops use. See CF-5 and figure the can is good for 20 U.S. gallons. Approved by many European car manufacturers. Not sold retail though. You have to buy through a repair shop/BG dealer. http://www.bgprod.com/products/fuelair.html

This stuff will clear up a car which has just narrowly failed emissions inspections, BTW. Just don't use 44K unless you have a seriously crudded up BIG car. Sometimes leaves metal in the sump!

[George S]

Thanks, Curmudgeon. There is a dealership right down the street from me that sells cf-5; i'll pick up a can.

[Curmudgeon]

Thanks, Curmudgeon. There is a dealership right down the street from me that sells cf-5; i'll pick up a can.

Great! Just don't use a concentration greater than a can per ~ 15 - 20 gallons. No harm in running the whole 15 - 20 gallons of mix through. Then you should be done for a while. Throttle response may improve noticeably or not. Let us know.