Mysterious 066/064 saw

[StihlBigBar]

Here are the details of a saw I just tore down and has me scratching my head

Crank case part numbers
1122-021-0700
1122-020-2900

Piston - 54mm
Cylinder mount bolts 5mms
066 base gasket does not line up with holes in case but lines up with holes on cylinder.

Cylinder will also not Accept a 6mm bolt, and cylinder also has decompression valve.

Cranks shaft has 8mm threads on fly wheel side and matching bearing sizes on both sides of crank

Here’s some photos. Any idea what it should be ?

 

[Mad Professor]

54mm and decomp makes me think 066/660 P/C but should fit 6mm screws. Are the cylinder screw holes slotted/filed to match the crankcase holes?

Is case threaded 5mm(064) or 6mm (066)? My IPl does not have #s for case halves, just case set of two.

8mm flywheel nut could be 064 or early 066. Flywheel aluminum? A flywheel and coil numbers might help.

I've not done a 064--->066 P/C swap, but know on 038S---> 038M the case and cylinder holes don't match up, and you need to slot the holes in the cylinder (but uses same 5mm screws).

Someone here will figure it out with a bit more info..........

 

[StihlBigBar]

54mm and decomp makes me think 066/660 P/C but should fit 6mm screws. Are the cylinder screw holes slotted/filed to match the crankcase holes?

Is case threaded 5mm(064) or 6mm (066)? My IPl does not have #s for case halves, just case set of two.

8mm flywheel nut could be 064 or early 066. Flywheel aluminum? A flywheel and coil numbers might help.

I've not done a 064--->066 P/C swap, but know on 038S---> 038M the case and cylinder holes don't match up, and you need to slot the holes in the cylinder (but uses same 5mm screws).

Someone here will figure it out with a bit more info..........

The case holes are 5mm and the cylinder holes are not slotted or modified saw came with no fly wheel but had a 2 bolt coil on it not the 3 leg

 

[Bob Hedgecutter]

Photo of the oil pump? Is is hose delivery to the oil gallery?
5mm, decomp and all that works out nice for a 640/650- but the 54mm does not.

 

[Mad Professor]

The case holes are 5mm and the cylinder holes are not slotted or modified saw came with no fly wheel but had a 2 bolt coil on it not the 3 leg

Some of the earliest 064 cases had 3-bolt coil mounts but came with either 3-bolt or 2-bolt coils (Bosch). Those coils had a different bolt pattern than the 2-bolt coils on other Stihls and the "universal "000-400-1300 coil.

Does the case have bosses for 2-, 3- or 4-coil mounts. The 064 came with 3- or 4-. The 4-mount will take either style 2-bolt coil.

Photo of the oil pump? Is is hose delivery to the oil gallery?
5mm, decomp and all that works out nice for a 640/650- but the 54mm does not.

Good point the pumps are different too.

 

[Bob Hedgecutter]

Did it come as a box of parts or was the cylinder on it? Piston could well be 54mm but if the cylinder is 52mm- problem solved!

 

[StihlBigBar]

Piston and cylinder were on the saw - the saw also had a ms660 style tank on it. The saw has the oil pump with the hose barb on it. It has only 2 bolt holes for the coil

 

[Bob Hedgecutter]

Piston and cylinder were on the saw - the saw also had a ms660 style tank on it. The saw has the oil pump with the hose barb on it. It has only 2 bolt holes for the coil

Well your cases and oil pump say 064 to me.
Now I believe early alloy flywheel 066 had the lighter crank with smaller oil seal, 8mm nut, thin recoil cover AND 5mm cylinder bolts- but as such should not have a decompression valve- sure this is not retro fitted?

 

[StihlBigBar]

Well your cases and oil pump say 064 to me.
Now I believe early alloy flywheel 066 had the lighter crank with smaller oil seal, 8mm nut, thin recoil cover AND 5mm cylinder bolts- but as such should not have a decompression valve- sure this is not retro fitted?

If it was retrofitted it was done poorly - there was no modification to the gasket or the cylinder to make it fit properly. The case and tank were filthy when I got them (they were combined) and so I would assume it was running in the odd state that I got it, or maybe not

 

[Bob Hedgecutter]

If it was retrofitted it was done poorly - there was no modification to the gasket or the cylinder to make it fit properly. The case and tank were filthy when I got them (they were combined) and so I would assume it was running in the odd state that I got it, or maybe not

No you could well have a saw made from the parts bin- but I was meaning the decomp valve itself- could it have been fitted to an old no decomp 066 54mm cylinder to help ease starting.
The old flat top 066 can come back and bite you with no decomp.