Bonneville America Forums Forums Technical Forums General Tech Nasty valves...

Gents,

Here's the situation:

I've been gone for a year and my baby sat (06' America). When I got home, as expected it didn't run but for a few minutes before dying. I attributed to my own dumb self for not draining the gas before the long sit. I yanked the carbs to give em a bath and just before re installing I took a flashlight and looked into the head just for the heck of it. From what I can see the bottom side of all 4 valves (stem side) are pretty nasty. When I say nasty I'm not just saying discolored- these things are cruddy as all hell.

The bike only has 9K miles on it. Mods performed include AI removal, rejet carbs, and a custom exhaust of my own concoction.

So the question is whether or not this is normal out of of a relatively low miles bike? I don't want to slap my carbs back on and hope all is well if there may actually be an underlying maintenance issue.

My initial thoughts are that it's running way to rich and what Im seeing is a residual gunk burned onto the valve. Second thought is that I may have some type of an oil drip into the head. That one seems like a longshot though because its all 4 valves equally and the bike doesnt smoke when running.

Or this could all be in my head and these Limey engines are prone to looking like filth on the inside.

Any thoughts from the thinktank? Thanks.

Nick

Take a closer look at your air/fuel mixture and run some Seafoam in your next tank for the heck of it. I saw the same thing miles ago and it hasn't slowed me down yet.

Thanks for the info. I'm ashamed to say that in all of my carburetor disassemblies I have yet to mess with the air/fuel mixture screw. In fact, I dont even remember seeing it when I took them apart.

Are you aware of any good tutorials on here which enlighten the mysteries of this....

Thanks.

Those screws have been discussed quite a bit, adjustment is easy. Disconnect one plug wire and ground turn the idle up just far enough to idle on the one cyl., turn the mixture screw in until the engine starts to run rough, then back out again until it runs rough counting turns between the two points. The correct setting is 1/2 way between the two points.

I disagree with Ian about how to optimize carb tuning.


If you want to see truly nasty valves check out an EFI direct injection motor.