1997 XP 787 Rotary Valve missing o-ring

[GrupaNation]

Can anybody comment on the condition of my rotary valve components? Pictures are attached.

I took off the rotary valve and cover today on my 97 XP. There were some minute scratches in the cover that were big enough to feel with a finger nail but not with just running a finger over them. The valve looks okay, albeit a little dirty on the crank side.

I did find that there was NO o-ring between the valve cover and the block! I'm assuming missing this oring is the cause of the hard start problems I've been having. Is that a correct assumption?
I checked the valve clearance using a feeler gauge and I could insert a .010" gauge fine but a .012" gauge would not insert freely.

Are there any parts I should replace besides the o-ring while i have it apart?

 

[etemplet]

In picture 149 there is a shiny spot on the rotary valve near the inside fit (bore/spline), why is it shiny? Is it rubbing something? Is there a raised area on the housing or cover plate. Since this is just visual VIA a picture it may be nothing. From what you describe, I don't think you need to do anything else. Your valve clearance is great.

Question - Since there was no o-ring in place was there RTV or some type of sealant on the cover? You may well have been drawing air into the combustion chamber as a result.

 

[mikidymac]

With no o-ring your lucky that didn’t run away or seize. An air leak there is typically a death sentence for an engine.

 

[GrupaNation]

Question - Since there was no o-ring in place was there RTV or some type of sealant on the cover? You may well have been drawing air into the combustion chamber as a result.

Answer: no gasket, rtv, or any adhesive whatsoever, just bare metal as seen in the pics.

As for the "shiny spot"... that is the crank side of the valve. There's just some corrosion built up and tint (for lack of a better term) on that side of the valve. The shiny spot is just a cleaner spot on the valve. I took some 800 grit sandpaper and carb cleaner and scrubbed away the little bit of build up. That has made it shiny and smooth once again without taking away any material.

 

[GrupaNation]

With no o-ring your lucky that didn’t run away or seize. An air leak there is typically a death sentence for an engine.

Thanks miki! I will be ordering a new o ring from SBT asap.

 

[mikidymac]

I suggest OEM on the o-ring.

SBT might work but I really haven’t seen anything quality coming from them.