Timing case and oil pump mounting stud thread sizes

What size threads were used on 1966 crankcases? I want to clean up both my timing case threads and the oil pump mounting stud threads.

In addition, how long should the 12 screws holding the timing case be. My workshop manual just states short, medium and long.

well there all 1/4 26tpi Cycle thread you need to clean out thread holes with

and drill and a place of cloth round it, as dirt and other gubins get in the bottom , be very mythodical, yours AJD

The main threads facing you on opening the timing cover will be 5/16" Cycle 26tpi. However, the buried ends of the studs are not the same.

The camshaft tensioner studs are 5/16" 26tpi cycle at one end and 5/16" Whit into the casing. They are both roughly 1.125" long and according to the maunal there should be 0.5" of thread on each end.

The oil pump studs are very rare in that both ends have Cycle threads of 5/16" 26tpi. They are roughly 1.75" long with just over 0.5" of thread on each end. They must be very similar to those used on the top front of the Heavy Twin barrels.

The Timing Cover studs should be 1/4" Whit 20tpi. (or UNC) They used to come in 3 length sizes positioned as in attachment. This appears to have changed to just 2 sizes during the Commando era.

Previously Phil Hannam wrote:

â?

The oil pump studs are very rare in that both ends have Cycle threads of 5/16" 26tpi. They are roughly 1.75" long with just over 0.5" of thread on each endâ?

Norvil has them on stock part-no 067598

Fritz

Previously fritz_wettstein wrote:

Previously Phil Hannam wrote:

â?

The oil pump studs are very rare in that both ends have Cycle threads of 5/16" 26tpi. They are roughly 1.75" long with just over 0.5" of thread on each endâ?

Norvil has them on stock part-no 067598

Fritz

This is correct. The original part numbers being T0247 for the tensioner studs and E4440 for the oil pump studs.

The main threads facing you on opening the timing cover will be 5/16" Cycle 26tpi. However, the buried ends of the studs are not the same.

The camshaft tensioner studs are 5/16" 26tpi cycle at one end and 5/16" Whit into the casing. They are both roughly 1.125" long and according to the maunal there should be 0.5" of thread on each end.

The oil pump studs are very rare in that both ends have Cycle threads of 5/16" 26tpi. They are roughly 1.75" long with just over 0.5" of thread on each end. They must be very similar to those used on the top front of the Heavy Twin barrels.

The Timing Cover studs should be 1/4" BSF 26tpi. They used to come in 3 length sizes positioned as in attachment. This appears to have changed to just 2 sizes during the Commando era.

BSF post 1963, yours anna j