AMC Gearbox colour...!?

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B+Bogus

B+Bogus

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I've just stripped the gearbox down to inspect, and (of course) to replace the layshaft bearing with a superblend.
I'm pretty confident the box has never been apart, and the original Portuguese layshaft bearing was still in good order (does this make it a collector's item? ;).
Everything looks great, except the shell is painted silver... it's peeling, and it's ugly.
Did they paint all the shells?

Should I re-paint it, or just strip and polish...? (daft question as I've no intention of painting it again, unless there's a bl**dy good reason!)
Anything else to look for while the box is apart?

I'm starting to enjoy working on this...apart from the head being pried off with a screwdriver at some stage, it seems in mechanically good shape :D
So far, the only noticeable wear is the cam (one lobe well on it's way), the rocker spindles and the piston rings - even the valves seem pretty sound.
 
Nortons painted, on the later models at least, the crankcases, cylinder head and gearbox shell silver. This was presumably a response to the type of nit-picking road tester who exists even today. They ride someone else's motorcycle for a month in the middle of winter, don't clean it at all, park it outside and then complain when the alloy goes furry.

Very few owners re-paint when doing a thorough restoration. The best option in my opinion is vapour bead blasting or otherwise a scotchbrite pad in hot detergent. Both of these leave a nicely 'sealed' surface.
 
Its worth painting the box case with a durable engine enamel. Reason is that the end of the rear mudguard has a couple of inches of gap above the swing arm and all sorts of road mess gets chucked up ont to the back of the box. corrosion is the chief issue and its a bugger to clean in there. I attached a flap of inner tube to the lip of the guard and it acts as a barrier between the tyre and swing arm.

Mick
 
Later Commandos and i beleive all 850s had painted engine and gearbox supposedly to counteract pourus castings. I would be interested to know when they started painting castings
regard Al
 
Tickling the Amal carbs causes gasoline to drip on the back of the crank case. I've tried different "rattle can" paints over the years and found none to survive very long. I suppose a good catalized urethane or enamel might be OK, but my current choice is to clean them with Simple Green and a Scotch pad. I like the look of a clean natural casting.
 
I appreciate the advice, guys.
I've got the cases stripped and cleaned up, and I think that's how they're going to stay...least effort!
Once the paint came off the casing was mint!
I'm not too concerned about the road grime issue, as it'll be a summer day ride only (yup - typical fairweather biker :oops: )

I'm ready to put it back together with the layshaft superblend, and I note that the old bearing positively located the layshaft, whereas the new one won't. Is this an issue?
 
B+Bogus said:
I appreciate the advice, guys.
I've got the cases stripped and cleaned up, and I think that's how they're going to stay...least effort!
Once the paint came off the casing was mint!
I'm not too concerned about the road grime issue, as it'll be a summer day ride only (yup - typical fairweather biker :oops: )

I'm ready to put it back together with the layshaft superblend, and I note that the old bearing positively located the layshaft, whereas the new one won't. Is this an issue?
Click to expand...

A fairweather biker in the sunny North West eh ? Good luck !

Layshaft end-float can be an issue - Have a look at the 'Old Britts' site

http://www.oldbritts.com/ob_start.html

Under 'General' you'll find a tech hints page dealing with gearbox assembly, including end float.
 
If I remember correctly only cases that failed the pourocity test were painted. A little bit of Devcon usually cures any problem.
Cash
 
Andy
I use PJ1 Yamaha Sport Silver on Engine Case, Head and Gearbox. PJ1 Gloss Black for the Barrels...
Nice even colour and coats well. I finish it off with 2 coatings of Mother's Pure Carnauba Wax.

cheers
CNN
 
79x100 said:
A fairweather biker in the sunny North West eh ? Good luck !
Click to expand...
Oh yes....you're talking to the eternal optimist here - I even installed solar panels on the house :shock:
I'm so deluded I believe I can build an oiltight Britbike!

79x100 said:
Layshaft end-float can be an issue - Have a look at the 'Old Britts' site
Click to expand...

Thanks for the link - seriously useful stuff!
I just did a dry run gearbox assembly with the superblend fitted and it seemed to be very tight end-float wise...until I gave the kickstart shaft a light tap - looks like I'll need to put about 40thou of shims in!
Now I'll need to make a tool to get the clutch actuator assembly off :(
 
I don't know about that Dave, I have a buddy that has a Guzzi shop that told me someone traded in a Triumph once and it was leaking oil so bad he drained all the oil in the tank, engine and gearbox and it still was leaking oil a year later. He says the thing was making oil.
 
Hortons Norton said:
I don't know about that Dave, I have a buddy that has a Guzzi shop that told me someone traded in a Triumph once and it was leaking oil so bad he drained all the oil in the tank, engine and gearbox and it still was leaking oil a year later. He says the thing was making oil.
Click to expand...


Some say the British aren't known for their computers because they couldn't figure out how to make them leak oil!





My Hinckley Triumph hasn't leaked a drop of oil in the nearly three years I've had it - or burned it either. Going on 26,000 miles.

Norton's down to only a drop or two every few days.
 
I've had 2 oiltight Bonnevilles (out of 4) and 2 oiltight Tridents (out of 2).
My current Bonneville still leaks after God knows how many tear-downs. I've pinned the latest one down to the gearshaft/primary case bush (new parts built not-to-the-drawing :x ). The most frustrating was a gearbox leak which I finally pinned down to a gearbox sprocket with an inadequate recess for the O ring, which just squeezed its way to freedom...always reminded me of what a hernia must look like :shock:
I've had this Bonnie for 25 years; it was (still is) nicknamed 'The Torrey Canyon'.

The first thing I noticed about the Commando is how much bigger all the joint faces are...quite reassuring!

Anyway...back on-topic... I discovered that a Triumph rear hub peg spanner fits the clutch lifter housing, and I was right about the shaft needing 40 thou of spacers :D
It's ready for reassembly, but I'll get a photo or two for nostalgia before I put it back together ;)
 
B+Bogus said:
I've just stripped the gearbox down to inspect, and (of course) to replace the layshaft bearing with a superblend.

Now I'll need to make a tool to get the clutch actuator assembly off

Anyway...back on-topic... I discovered that a Triumph rear hub peg spanner fits the clutch lifter housing,
Click to expand...

Sorry, but I have to ask...how did you manage to strip the box in the first place, with the lifter assembly still in position?

As the mainshaft nut behind the assembly would need to come off before the inner cover could be removed? [Edit] (unless the mainshaft timing side bearing was loose in the inner cover-possibly? [Re-edit] Thinking about it some more, there is an inner bearing retaining lip inside the inner cover, so the inner cover could not normally be removed without the mainshaft bearing also being removed?)
 
L.A.B. said:
Sorry, but I have to ask...how did you manage to strip the box in the first place, with the lifter assembly still in position?

As the mainshaft nut behind the assembly would need to come off before the inner cover could be removed? [Edit] (unless the mainshaft timing side bearing was loose in the inner cover-possibly? [Re-edit] Thinking about it some more, there is an inner bearing retaining lip inside the inner cover, so the inner cover could not normally be removed without the mainshaft bearing also being removed?)
Click to expand...

Nope! The mainshaft came out with the inner cover and the layshaft stayed in the main case. The only thing preventing the mainshaft being pulled out is the circlip for the clutch. Bear in mind that the high gear remains in the case.

I followed the Triumph route of pulling the selector fork pin out...perhaps this made the job easier? Anyway, it all came apart without having to disturb the T/S mainshaft bearing. And no big hammers were used - honest ;o)
 
Ah yes, I see,-thanks, not that I'd normally do it that way personally!




B+Bogus said:
Anyway, it all came apart without having to disturb the T/S mainshaft bearing. And no big hammers were used - honest
Click to expand...


Even Mick Hemmings recommends using a hammer and punch to loosen/tighten the actuator ring, as he says in his NOC gearbox rebuild video: "...and I still find this is the only real way with these rings to stop 'em coming undone..."
 
L.A.B. said:
Even Mick Hemmings recommends using a hammer and punch to loosen/tighten the actuator ring, as he says in his NOC gearbox rebuild video: "...and I still find this is the only real way with these rings to stop 'em coming undone..."
Click to expand...

Drops pipe and copy of Motorcycle Sport in shocked amazement!

I've reorganised my workshop...these days I've got the hammer further away, and the blowtorch closer - life is far more pleasant!
Seriously, I didn't have to swing on the sleeve nut to get it undone, but I did get the case good and warm first.
The mainshaft nut was an entirely different story - lots of heat and much application of impact air-wrench to get the bugger to move!

I suspect that a dab of loctite on the sleeve nut may be A Good Thing...?
 
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