Triumphrat

buckieleach

Does anyone know a reason why you couldn't use button head socket bolts instead of hex bolts or socket head bolts on the crankcase and sprocket covers. If you could find them long enough, I think they might look pretty good.

Forchetto

I think button-headed allen bolts are only made up to a maximum of 50 mm long.

Later on I can give you a list of the required sizes and quantities. (when I find the bit of paper with the data).

samc

It seems to me that button heads generally have a shallower hex socket (compared to socket heads), so they're more likely to round-off.

Forchetto

What Samc said. They have a smaller hexagon so they'll take less torque that regular cap screws. For your aplication the torque is only 7 Ft/Lbs so it'll probably be OK.

The shopping list is as follows:

M6 x 1.0 pitch, Button head Allen screws, preferably in Stainless steel.

1 off M6 x 16 mm
7 off M6 x 30 mm
14 off M6 x 40 mm
11 off M6 x 50 mm
5 off M6 x 75 mm

Total 38 screws that include all the outer engine cases including the gearchange selector cover (just under the Sprocket cover).

You might have a problem with the 75 mm ones. These are for the sprocket cover.

If normal allen stainless bolts are wanted, there's this ebay seller that's reliable and the well-presented product is good value:

http://cgi.ebay.co.uk/Triumph-Bonnev...item3ca74fed6f

Normandy

Button heads are "shoulder" bolts and will not seat properly on the covers.

buckieleach

Thanks for the info, guys. You're right about the 75mm, I haven't been able to find them yet.

Baltobonneville

Enlighten me: What is a "shoulder bolt"?

I wouldn't use the button heads myself because they might be harder to remove when that becomes necessary, as already mentioned.

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, Unifilter, no snorkel, 118/40/Thrux needle/1 shim/3 turns, tachometer, Ikon 7610s in back, Ricor Intiminators in front, Pirelli Sport Demons, D9 gauge panel.

Forchetto

I think we're confusing "plain shank" bolts with "shoulder bolts".

The former have a portion of the diameter under the head that's not threaded. The shoulder bolt is a threaded fastener with a plain, precision machined, shank that is used for location purposes. They are typically used for pulleys, linkages and on bikes for the brake and clutch lever pivots.

None of the casing screws are doing any oil sealing duties. The castings go around the screws and the gaskets seal all around them.

Shoulder bolt:


Plain shank bolt:

Normandy

Yea, button head shoulder bolts are holding your brake discs and your cam cover on. If it is like a button head with no shoulder then it is a round head or stove bolt, not as much strength but they would work.

Baltobonneville

Thanks, Forchetto.

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, Unifilter, no snorkel, 118/40/Thrux needle/1 shim/3 turns, tachometer, Ikon 7610s in back, Ricor Intiminators in front, Pirelli Sport Demons, D9 gauge panel.