Valve guides and seats.

[Kara25]

Ok so i dissasembled everything oh the 650 head i got and i run into two problems (?). First is that the valve stem seals were petrified so much that i was in a fight to remove them. I used needlenose pliers and managed to get them off but in the process i put small knicks/scratches on the opening of the guide. How serious is this? Can i remove any hard edge it might had with some polishing compound? the valves are moving in and out without problems in the guides no biding. Second is those pictures i am going to post here. when i removed all the valves i knew before hand there was some surface rust on cylinders 1&2. the seats were not that bad and after i spend around 5-6 minutes i got them down looking clean. the seat width measured with calipers on the head and on the coresponding valves measures beetween 1.05-1.13 mm. 650 manual says maximum seat width is 1.10 am i ok i assume the calipers are a little wacky but what do you think from the photos? did i remove too much material even though the measurement is lets say in the ballpark? 20221223_113905 by Geo 25, on Flickr 20221223_113836 by Geo 25, on Flickr

 

[Suzukian]

I can barely see any marks, but if you are referring to the very tiny ones, polish them smooth, as pieces of metal like that can get very hot and cause detonation. Once polished, IMHO, I think it's not an issue at all.

 

[Kara25]

Suzukian You sir just saved christmas.! Thanks for your input! What do you think about the knicks/scratch on the very top of the guide were the seals go? Will that be any problem if the valves pass the wiggle test and are moving freely in there ?? I am just trying to get an idea when is a guide trash. I hope not just from this misshap...

 

[Suzukian]

The guides are to prevent oil from getting in, as long as they seal on the outside, you should be fine. You could mount them, and blow some air through the valve end with a hose, have your finger over the seal, and see if any air comes out, then try sucking to see if you can generate vacuum. If you can, you're all set. I would not use pressurized air though. You're just trying to keep oil from sucking into the intake valves, and the vacuum isn't that much. It's very hard to create a lot of vacuum.

 

[chuck hahn]

Another trick to check the valve to seat seal is to finish any valve seat work and lapping and reassemble the valves. now set the head on a piece of cardboard with combustion dome up. Carefully fill each dome with water and let it sit for a while. carefully suck the water out and dry things out with a towel. Lift the head up and see if any valve has left a wet spot.

 

[Kara25]

Suzukian yeap i will try this test for sure i saw something similar where you have the valve in the guide and block the seal side with your thumb while trying slowly to remove the valve. If you let go and feel suction pulling the valve back in you are good to go. chuck hahn i already did that on chambers 1,2 that were the most dirty with moisture deposits after lapping poured kero in the chambers and left it alone for 30 minutes. Not a single drop. What you think about that much carbon deposit on the ports both exhaust and inlet??? After 3 baths with different degeasers and still not got all of it out. I assume it was burning oil but it must have been a real mosquito machine. Ironically all the shims that i got out were from 2.60 and upwards there was also a 2.80 in there i assume bigger shims means low milage? What are the shims with an (x) right next to the number? Found 2 of those.