V-Twin Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
62 Posts
Discussion Starter · #1 ·
Front head off of a '74 shovel has a crack at the exhaust valve guide on the top side (doesn't go all the way through), and part of the inner lip on the manifold side has broken off. I was told about the crack by the seller and he said it wasn't smoking when he had it running, but obviously it's not going to get any better on its own. There's also some sort of gasket or O-ring missing around the base of the guide that the other three valves have. I think the manifold flange damage may have happened during shipping, but it's too late to do anything about it now. Is there a possibility that it will still seal, or is it definitely going to leak? eBay heads are going for about $250 right now, but none of them are great and would all need work in some way or another. If I decide to run it for now and have to change it later, is there clearance on the FX to be able to pull the head with the motor in the frame?

Crack. It's obviously there, but I can't even fit a .0015" feeler gauge anywhere in it.
Automotive tire Automotive lighting Motor vehicle Automotive design Automotive exterior
Automotive lighting Automotive exhaust Automotive tire Gas Bumper


Manifold flange:
Automotive tire Gas Gear Auto part Personal protective equipment
 

·
Registered
Joined
·
39 Posts
I'll try to be respectful this time. LOL. Firstly, yes, there is room to remove the heads from your' shovel while in the frame. The crack near the valve guide may be repairable. If you pull the head and get the valve guide removed, it may be possible to weld up the crack and have a machinist clean it up to install a new valve guide. Being O-Ring heads, there are aftermarket kits to serve as band aids (pretty effective ones) for the damage to your intake port. This can also be repaired by visiting your' welder and machinist. I guess the short answer to your question is "not yet". If you find the crack to be irreparable, then you have options to Ebay, as S&S sells some pretty nice super sport heads to replace your' old ones. Personally, I'd try to save the H-D head, but I'm "that guy". LOL.
Best regards, Dean
 

·
Registered
Joined
·
9,975 Posts
As to the port,,, there is a kit that converts it to the late rubber band style seals,, pretty sure that would cover this problem effectively..

As to the crack at the valve guide bore... i would junk the head,,,, the casting is porous and weak. I would toss it... because,, yeah the crack can be tig welded,,, after all that and the guide bore machining required , the inside will need to be welded as well... the heat from welding, plus the sand casring,, will grnerally open another hole or crack, at the end of where the welding begins.. i don't waste time there... it is in a high stress area... do as you wil..
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #6 ·
As to the crack at the valve guide bore... i would junk the head,,,, the casting is porous and weak. I would toss it... because,, yeah the crack can be tig welded,,, after all that and the guide bore machining required , the inside will need to be welded as well... the heat from welding, plus the sand casring,, will grnerally open another hole or crack, at the end of where the welding begins.. i don't waste time there... it is in a high stress area... do as you wil..
I weld enough to know my limitations, and I can't argue with anything you said there. I guess the only other question is how likely is something like that to turn into a catastrophic failure where it drops a valve into the cylinder? Since it sounds like I can swap the head without pulling the engine again, if it's (likely) a gradual thing where it will just start burning oil and smoking once the crack spreads, then I may take my chances on it as-is and hope I can run across a better head in the meantime than what is available right now. As y'all may have gathered from my recent posts here, I want a good bike when it's all said and done, but I also don't have an unlimited budget.
 

·
Registered
Joined
·
9,975 Posts
In my experience,, when the failure occurs it is generally catastrophic,,,,
A pair of later model heads, will bolt right on,, from 82-83, will give all the last shovel upgrades,,, before it was discontinued... valve seals on the guides, better valve material and tougher seats,, with a better cast head..
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #8 ·
In my experience,, when the failure occurs it is generally catastrophic,,,,
A pair of later model heads, will bolt right on,, from 82-83, will give all the last shovel upgrades
That's a pretty compelling argument. I may look into going that route and selling the remaining good head that I've got.
 
1 - 9 of 9 Posts
Top