Triumphrat

motobob

I am doing a valve adjustment on a 75 Trident.
The left exhaust valve has no clearance, possible due to a pocketed valve. The bike has mushroom type adjusters and the top of the mushroom bottoms against the rocker arm before any clearance can be obtained.

It looks to me like those type adjusters cut down on the adjustment range and I am hoping substituting a standard type adjuster will solve the problem.

I really want to avoid pulling the head and shortening the valve stem.
Any suggestions appreciated.

Mr.Pete

I've ground mushroom head adjusters down to normal size.I found the extra diameter did nothing (it never made contact with the valve tip),and wasn't necessary.

Then I could screw them in from the top,like normal.The actual radius on the mushroom didn't seem much different from standard.

motobob

Thanks, you saved me a ton of work.

DAVE M

I've never quite understood the benefits of mushroom adjusters?

is it that the arc described by the original may be off a tad, and so the greater surface area provides a greater surface area to strike?

I have allen headed adjusters on mine, and it helps to have the key in while rocking the wheel so you can see the valves open from a greater angle.

JohnA

I'm glad to see I'm not alone in my scepticism about 'mushroom' head adjusters. As Pete says, no more metal is in contact with the top of the valve stem regardless and, furthermore, the weight of a mushroom-headed adluster must be greater than that of a standard one, at exactly the worst place for it!

Sounds like an annoying problem motobob - you can't even remove the mushroom adjuster without taking the rocker box off. Good luck with it anyway!

GrandPaulZ

The "pocketed valve" (sunken valve seat) seems like the real problem to me...

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motobob

I am sure the valve is pocketed. The question is how much? Is it an acceptable amount, that could normally be given proper clearance with stock adjusters?

To me it looks like you lose quite a bit of adjustment range with the mushroom type. I can move the rocker sideways a bit, but am not able to get even a thin feeler guage under it.

As soon as I remove the rocker box, I will do a leakdown test on the cylinder and check valve seating condition.