Topic: Retrofitting seals on K1 exhaust guides

[AbbyRider]

I'm using a low mileage K1 head on an F2 motor. Exhaust valve guides are the old style with no machining for seals. The guides and valves are fine, so no need for replacement, but based on other threads it sounds like I'll be dealing with a whole lotta smoke. I'm wondering if it would be plausible to machine the outside of the existing guides so that they'd be able to accept the seals, and more importantly, keep them in place? Or is it not worth the bother. I've got a frame kit, so I could always try them as-is and then if the smoking is too much, figure out what to do with it at that time. Would be nice to figure out a fix beforehand though.

[lucky]

If you are using a K1 head I do not see a problem. Just use K1 valve guide seals.
"Exhaust valve guides are the old style with no machining for seals."

You better get that all straightened out before you start it up.
Otherwise you will be taking it all back apart.

Are you using all K1 cylinder head parts??? Or are you mixing parts?

[CB750F2]

Please be aware that if you are using the K head on top of the F2 barrels you will need to modify four of the drain back holes so that the oil from the cylinder can drain back into the crankcase. This is needed because the F2 head uses four of the cylinder studs to drain back the oil while the K head uses eight. The mod is easy to do and I think it has been described here. Pat

[AbbyRider]

Pat - yes, thanks for the reminder. Will be doing that work this weekend. Was still hoping for someone knowledgable to chime in on the guide seal issue. From what I've read, it sounds like most people that have the old style guides without seals are fine - just have a bit of extra smoke to contend with. I'll probably just leave as is.

[AbbyRider]

Pat - you don't happen to know if there's any photo documentation of the drain back joining process? I've looked here on the forum and haven't found any.

[scottly]

Are you using the F2 pistons with a K1 head?

[MRieck]

Pat - yes, thanks for the reminder. Will be doing that work this weekend. Was still hoping for someone knowledgable to chime in on the guide seal issue. From what I've read, it sounds like most people that have the old style guides without seals are fine - just have a bit of extra smoke to contend with. I'll probably just leave as is.

I strongly recommend changing those ex guides

[CB750F2]

I cannot find any photos of the mod required to the F2 cylinders but I think that all that is necessary is to cut a groove at the bottom of the four unused drain holes. In my searching I found that a member did not do the mod and the oil just builds up and flows down the cam chain opening - not a problem. I prefer to cut the grooves and allow the oil to drain back as designed in the K cylinders. I have finally acquired a K4 head that may be suitable for my situation - similar to yours - and I am deciding what needs to be done to it before I can use it. Pat

[AbbyRider]

Pat - yes, thanks for the reminder. Will be doing that work this weekend. Was still hoping for someone knowledgable to chime in on the guide seal issue. From what I've read, it sounds like most people that have the old style guides without seals are fine - just have a bit of extra smoke to contend with. I'll probably just leave as is.

I strongly recommend changing those ex guides

Thanks Mike. Duly noted. I do have exhaust guides coming to me from Dynoman. Just don't have the budget to do the full valve job (recutting seats etc) right now. So depending on how long the full build takes me, I might end up running it as is for a bit. Beauty of the frame kit is that I'll have the ability to do the changes relatively easy. If I'm going to end up replacing the guides at some point, think there's any harm in trying to fashion a groove in them to accept the seals? Would it cause potential harm if one or more of them were to dislodge? Doesn't seem like they'd be able to go too far.

[MRieck]

Pat - yes, thanks for the reminder. Will be doing that work this weekend. Was still hoping for someone knowledgable to chime in on the guide seal issue. From what I've read, it sounds like most people that have the old style guides without seals are fine - just have a bit of extra smoke to contend with. I'll probably just leave as is.

I strongly recommend changing those ex guides

Thanks Mike. Duly noted. I do have exhaust guides coming to me from Dynoman. Just don't have the budget to do the full valve job (recutting seats etc) right now. So depending on how long the full build takes me, I might end up running it as is for a bit. Beauty of the frame kit is that I'll have the ability to do the changes relatively easy. If I'm going to end up replacing the guides at some point, think there's any harm in trying to fashion a groove in them to accept the seals? Would it cause potential harm if one or more of them were to dislodge? Doesn't seem like they'd be able to go too far.

         How would you cut such a groove? I honestly have no idea how you would set that up. It is not like a Chevy guide cut for an umbrella. Knock those guides out, put in fresh guides and cut the seats.
 Ask MC Rider about those guides....his head is sitting in my shop with those ex guides that were just replaced. In 20 minutes of riding the exhaust ports are full of oil (3 ports still holding LIQUID oil). I have done other heads with the early ex guides installed....all with big problems. Granted several had the guides installed like a$$ BUT they all drop a ton of oil. I do think they ran them so tight out of the factory they would actually hold some oil. Plus....in the 60's everything burned oil so who knew or cared differently.
 If you don't care about pulling stuff apart...and waste the gaskets etc go for it. If you want to do it once do it once. BTW....those Kibblewhite guides fron Dynoman will need to honed (NOT reamed)....figure that into the cost as well.