dps650rider
XS650 Addict
Is there an O ring seal between the valve guide and head?
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Valve Guide Question
- Thread starter dps650rider
- Start date
No o-ring.
There's a metal cup seal with a garlock seal molded into it that caps the guide.
Between the head and guide, yes, I think there is, but I've never had one out to know for sure. But, new o-rings for the guides are included in the Athena complete engine gasket set so I assume they are in there.
dps650rider
XS650 Addict
I have a nos guide and there is no groove for an o ring, maybe it's in the head?
Yep, there's no groove in the guide, but the hole for the guide - in the head - is beveled and will accept the O-ring. The O-rings are often red rubber
p/n 93210-15151
p/n 93210-15151
dps650rider
XS650 Addict
I have not.
Well sumbich. Never knew that. I've replaced guides on literally dozens of different types of motors. Never seen even one with an o-ring in there. They're an interference/press fit. What's the point?
dps650rider
XS650 Addict
I have been trying to decide what is causing the black deposits on the intake side of the right plug (see link below). Talked to several people and no one has ever seen one like it. I talked to RD and he has occasionally seen a problem with a leak between the guide and head.
Since the bike runs great, gets 60+ mpg and the oil consumption is not all that bad I'm thinking that oil is making a pretty direct shot at the plug. And BTW did a top end job last winter with boring pistons and valve seals. I'm concerned I'll take it apart and won't find anything.
https://www.xs650.com/threads/black-and-white-spark-plug.64586/
Since the bike runs great, gets 60+ mpg and the oil consumption is not all that bad I'm thinking that oil is making a pretty direct shot at the plug. And BTW did a top end job last winter with boring pistons and valve seals. I'm concerned I'll take it apart and won't find anything.
https://www.xs650.com/threads/black-and-white-spark-plug.64586/
Oh, well you can measure the guide bore in the head and the guide OD. The specs for the interference fit are in the older manual: -.0015" IIRC. Oversize guides are (were) available. You may also want to check the clearance on the valve stem to guide ID clearance: IIRC .001" to a max of .003"
It is an unusual issue that I've not seen first-hand
It is an unusual issue that I've not seen first-hand
dps650rider
XS650 Addict
Pretty weird... I've had valve seals fail from a combination of not enough clearance and too many rpms and the plugs didn't look like that. And I've had excessive oil burning from worn bores and again plugs never looked like that. Only other thing I can think of is a head gasket problem.
I am not convinced that the O ring is needed considering that you have to heat the head pretty hot to loosen the guides and they still need to be driven out. Also the contact area of the guide and head is quite long. Just my thoughts other posters will have different ideas.
Agree.
AUTOMAN
XS650 Addict
I've seen multiple guide to head oil leaks on Vipers and Hemis.
Slight gouge or debris snowballs into severe score direct path from rockerbox to intake port.
cliff
ps
i thought you had this fixed via carb?
Slight gouge or debris snowballs into severe score direct path from rockerbox to intake port.
cliff
ps
i thought you had this fixed via carb?
dps650rider
XS650 Addict
I thought so at first too. I swapped engines using the same carbs, ign, etc and had a little black on that plug but I cleared it up with fixing the carb bowl gasket and choke. Swapped engines back and the black is back. I had suspected it was oil and gas both so now I'm left with oil.
