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I've just done the mod as detailed in the old Suzuki forum posts - and still up on Bwringer's site.
I have a couple of possibly useful updates.
It is possible to do it with the head still on the engine - and still in the frame. With the buckets removed, the cams can sit down in the bearings with enough clearance for a small amount of rotation.
For those who worry about marking the lobes on the valve stem tops, cut cardboard circles and drop them on top of the valves.
Leave the spark plugs in. At some point in the process you will drop a cam cap dowel. Best if not inside the engine....
I found that on this engine all the wear was on the left - or downhill side when on the sidestand. So only inserted that side. Clearances before starting were .0055in inlet and .0075in exhaust.
Finished - -002in both cams.
I made the half moons by holesawing out blanks from 4mm 6061 alloy sheet then machining. Parting off accurately at what is a fairly large diameter for a home lathe, I try and avoid.
Measuring showed I needed inserts approx 3.9mm thick so the 4mm sheet was ideal.
When doing the final clearancing - hand rubbing the inserts to thickness - it's worth ensuring the inserts are fully seated in the machined recesses.
I used a block of wood and a small hammer to tap the end of the cam across to push the inserts fully home.
When doing this, you of course only need fit the cap which holds the insert.
If I did another one, I think I'd use bronze rather than alloy for the inserts. That's a very narrow thrust face. No expansion probs either, and the insert is locked in place anyway.
I'd be curious to see if anyone else has done it and if there are any other solutions out there. Most modern engines now use a narrow steel half moon running in a slot in a cam bearing journal for location. Can't do that on the 8V GS basically because of the overhung end cam lobes. Don't want to break a cam.
Another way which came to mind is using a hard overlay on the cam locating flange to build it up. Not difficult I'd think but the risk is cam distortion if it's overheated putting the overlay on.
I have a couple of possibly useful updates.
It is possible to do it with the head still on the engine - and still in the frame. With the buckets removed, the cams can sit down in the bearings with enough clearance for a small amount of rotation.
For those who worry about marking the lobes on the valve stem tops, cut cardboard circles and drop them on top of the valves.
Leave the spark plugs in. At some point in the process you will drop a cam cap dowel. Best if not inside the engine....
I found that on this engine all the wear was on the left - or downhill side when on the sidestand. So only inserted that side. Clearances before starting were .0055in inlet and .0075in exhaust.
Finished - -002in both cams.
I made the half moons by holesawing out blanks from 4mm 6061 alloy sheet then machining. Parting off accurately at what is a fairly large diameter for a home lathe, I try and avoid.
Measuring showed I needed inserts approx 3.9mm thick so the 4mm sheet was ideal.
When doing the final clearancing - hand rubbing the inserts to thickness - it's worth ensuring the inserts are fully seated in the machined recesses.
I used a block of wood and a small hammer to tap the end of the cam across to push the inserts fully home.
When doing this, you of course only need fit the cap which holds the insert.
If I did another one, I think I'd use bronze rather than alloy for the inserts. That's a very narrow thrust face. No expansion probs either, and the insert is locked in place anyway.
I'd be curious to see if anyone else has done it and if there are any other solutions out there. Most modern engines now use a narrow steel half moon running in a slot in a cam bearing journal for location. Can't do that on the 8V GS basically because of the overhung end cam lobes. Don't want to break a cam.
Another way which came to mind is using a hard overlay on the cam locating flange to build it up. Not difficult I'd think but the risk is cam distortion if it's overheated putting the overlay on.
hmm, what bushings do I have around..could I just cut a section off one and use it for a shim..? But perhaps it'd be harder to hold in place and not last as long either...)OR it could nest in that plastic end cap?..........)
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