Today I broke a valve guide

[Ajohnson]

Let me introduce myself by saying im just beginning my GS journey, got an old clunker to bring back to life this winter. This is my first excursion into motorcycle mechanics, ive done plenty of small engine work and have a friend with professional experience to help me.

Realistically how difficult is this broken valve guide going to be to remove? Will the generic 'valve guide removal tool' that you pound with a hammer work?

 

[Nessism]

Removing a valve guide is not a trivial task. The valve seat will have to be cut after replacement, for example, because there may be some misalignment created. Also, the ID of the guide reamed to exacting dimensions. That right there typically puts the job into the realm of the pros. Also, depending on how the old guide is removed, and some luck, you may need an oversize valve guide. It's not uncommon for some aluminum material in the bore of the guide to be lost when the old guide is removed, and when that happens, the hole needs to be reamed, and an OS guide installed. Using heat before removing the guide is helpful, but that in itself is not easy either. If you have an old oven, put the head inside for an hour to heat it up before removing the guide, that will expand the aluminum, and reduce material loss.

 

[Redman]

(I think this thread lost a couple postings in the forum upgrade last week).

Am intested in te subject because the shop (personal friend) that rebuilt (valve seals, lapp valves) a head (1100G) for me said that a valve guide broke while replacing vlavle seal. AN then another. So it was taken to machine shop to replace the guides, and that shop reported some difficulty. Now, a few years, and not a lot of miles later, the engine blows smoke on startup (especailly if sat for more than a few days) and puffs on decell. SOmetimes I come home from a ride, and later in day when walk past closet I can smell the burn oil smoke comming off my jacket. Anyway........
I am interested to learn a little more about this subject.

 

[chuck hahn]

Replacement guides are oversized diameter. Ream after head has cooled to room temperature. This requires the holes be reamed and i believe it is to 12.2MM. Best to heat head at 450 degrees for half hour to expand the aluminum well to make removal much easier. Use a guide tool for removal and insertion. Oil replacements before insertion and be sure they are completely down to the retainer ring. Let head cool and thats basically it.
Remove old seals by heating them real good with a heat gun to soften the rubber. Dont get crazy taking them off either. pull as straight up as possible and do jot try prying them up.. thats what snaps guides faster than anything.
I personally take the propane torch and burn the seals good and then use the Dremel to clean the guides. You melt the rubber a bit and needle nose pilers just lift the remains out of the well.

 

[Signal]

A method I have used to remove valve guides although not on a GS.
1 Bead blast valve head side of the guide to remove built up carbon and deposits. This is supposed to help stop scratching and oversizing the guide hole in the head.
2 Make a mandrel that fits the guide one end and fixes to an air hammer the other.
3 Heat the head as described above
4 After heating support the head on wooden blocks and drive the guide out using the air hammer.

The guides come out very easily.

 

[Nessism]

(I think this thread lost a couple postings in the forum upgrade last week).

Am intested in te subject because the shop (personal friend) that rebuilt (valve seals, lapp valves) a head (1100G) for me said that a valve guide broke while replacing vlavle seal. AN then another. So it was taken to machine shop to replace the guides, and that shop reported some difficulty. Now, a few years, and not a lot of miles later, the engine blows smoke on startup (especailly if sat for more than a few days) and puffs on decell. SOmetimes I come home from a ride, and later in day when walk past closet I can smell the burn oil smoke comming off my jacket. Anyway........
I am interested to learn a little more about this subject.

Schumann Motor Works has a good reputation, charging $380 for a full head rebuild, with new guides. Life is short, so if the cost isn't a killer, just send them your head and rest easy.