Michigan eh! Maybe, who knows?!
Its kind of inevitible that these bikes will have mix and match parts , there are very few that survive totally stock with a service history.
Heres more tips.
You wont find a wiring diagram for this model in a Haynes manual
, I use the diagram from a triumph manual
covering the oil in frame t120s T140s, they are identical in loom layout and colours. New main looms and Headlamp looms are still available and easy to hook up when you are on the rebuild.
The key differences on the 71 motor from earlier motors are as follows.
Engine primary case threads are 1/4 UNC
Rocker cover is held by 5/16 fasteners, and has 2 x 5/16 UNF tapped holes in a boss for mounting the head steady.
The primary outer should have
a strobe inspection cover, 4 c/sunk 2BA screws.
2 slotted covers for clutch centre and chain tension
2 additional oil drain and level screws.
Internally the crank was machined all over,
iron body oil pump, slightly beefed up con rods.Thicker gasket faces, thick flange barrels.
Externally exhaust pipes should have a balance pipe just in front of the head, this helps top end performance and really helps keep the pipes in the head.
Not much changed in the gearbox, the cam plate got stiffening brackets.
The motor still contains a mix of cycle threads and updated UNC UNF , be careful with the nuts and bolts , bag and label to prevent confusion.
Things to budget for
later gas taps (triumph type), the push pull plungers with corks are historically interesting and very prone to leaking, the corks shrink speshally with modern gas.
Clutch parts, the centre cush drive wears and allows the whole assembly to tilt, check drive vane and end plates, drill out punched part of the thread lock to dissasemble.
new friction and drive plates , if the outer hub sprocket isnt too worn you can get by with filing the drive slots level.
Exhaust valve guides and valves ( the guides are nearly always shagged) I like to use iron guides they last longer.
Re cut v/v seats.
New rings/ rebore if needed ( I dont like unneccessary reboring), usually new rings will do, theres only 3 oversizes ,
New big end shells.
New timing side bush. Vital for healthy oil pressure.
This is a biggy, do a search on this on the site for loads of previous. If you have a big budget and want loads of miles/ tuning, then spring for an end fed crank conversion, its good for peace of mind. My motors have these and I never worry about caning them.
Selector forks and cam plate, cam plate punger.
if the clutch has been slipping / dragging, the selector forks will be bent or blue, the cam plate will be chewed up.
Rubber bits, oil , UV seems to eat these up
The OIF has a lot.
Front to back
Head lamp mountings.
Tank mounts centre and frame tube.
Steel side panel mounts.
Viton tipped float needles, new slides , needles and needle jets.Throttle cables
Thatll do for now.
The above is all from bitter experience, I got my OIF A65 in 1981, it was my main ride for twenty years.
Do searches here on site
for clutch centre removal.
Also I totally reccomend you read LD Bennetts tech articles on the "piled arms" site, particularly for a great explanation of the timing side crank bush debate.
hey I might have been quicker just flying out!