TM #1 & subsequent threads will cover mechanical tools...both OEM & substitute:

OEM Magneto/Sprocket holding tool. This one is for the HT/LT/AT/CT models. Length is 8 x 3 &1/2 inches. Large lugs are 2 & 5/8 inches center-center & small 1 & 5/8 center-center. A slightly larger one was made for the DT/RT Enduros. However, an even better solution for holding a magneto is to use a large rubber strap wrench. So long as the rim of the magneto is clean & dry, this is a better tool for the job. It is also less apt to slip like the OEM tool & scratch up the magneto (or your knuckles!) in the process. Older is not necessarily better...

Magneto Pullers. The chromed T-Handle is the early Japanese model. The other is a current version offered today. I believe these are 26mm reverse threaded.

OEM Clutch holding tools. The smaller one is for the HT/LT/AT/CT & is 4 & 7/8 inches in diameter w/20 teeth. The larger DT/RT holder is 5 & 3/8 inches in diameter & has 27 teeth.

Piston Pin Puller/Installer. This tool is currently in production & comes with 4 plugs to accommodate most piston wrist pins.

I have found the best magneto holder is a thick, rubber belt, plastic handled strap wrench. I have used this exclusively on numerous Enduros and it has never failed to secure a magneto, allowing me to remove the lock nut. You can get them just about anywhere. The benefit is, not being steel, it won't scratch up the magneto or slip out of the slots in the face. There are only two provisos. First is to make sure the outer rim of the mag is clean, oil-free, & dry. The second is you must remove the left sidecase and/or magneto coverplate to get access to the rim of the magneto. There are two sizes of strap wrench. Craftsman makes a large one in red plastic having a rubber belt measuring 26 inches long x 3/4 inch wide x 1/4 inch thick (see this pictured in TOTT introductory thread). The yellow Mastergrip (below) is similar in proportions. There is also a half-size one as well. This works equally good for smaller jobs, so get one of each.

TM #2:

OEM Case splitting tool. This consists of a bracket, handle, shaft & two pair of 8mm bolts. It is good for nearly all Enduros. The second splitter is a Proto H-Bar that can be used with shimmed 8mm bolts. On the example I have, the two slots were filed just a bit wider. This allows DT1 head bolts to slide into the slots. By doing so, it can be used to help remove a piston which has become stuck by rust or seizure from it's cylinder. Should also work for smaller displacement Enduros, too.

Chain Breaker. This is one of several patterns of tool for working on removing chain links.

Impact Driver. As mentioned in the initial thread, this should be in your basic toolkit. With a good selection of driver bits and adapter for metric Allen wrenches, it is one of the most useful tools you will need when installing or removing screws.

T-M3:
Spoke Wrenches. A small adjustable or open end wrench will usually suffice if you cannot find these special wrenches. Width of notch is marked on tool.

Feeler Gauges. Either metric or SAE will work for your needs.

Metric Micrometer. This is a useful tool for quick reference. A model with a dial indicator is even better...

Compression Tester. A good item to have, particularly if your cycle is experiencing a loss of performance, or you suspect a bad crankcase seal, etc.

TM #4:
Yamaha OEM Dial Indicator Kit. This unit is primarily for the CT1 & smaller displacement cycles. It came with one small & two long extensions, the stand, and a dial indicator with 4mm swing, circa 1970.

Yamaha OEM universal dial indicator stand. This is a later made unit & adapts to most dial indicators.

Yamaha OEM dial indicator stand for the 1971 & later DT1. Constructed of cast steel like the OEM case splitter bar. This was specifically for the later cycles which necessitated removal of the cylinder head to get accurate measurements of TDC & BTDC.

Improvised 1971 DT1 dial indicator stand. I opted to place this item here next to the OEM stand rather than under the 'Improvised" tool header. This was made of existing materials & a DT1 headbolt which was modified to make the standbolt. Easily made if you have some time & patience. A small lathe or mill would make a big difference. Can also be modified to accommodate your preferred metric dial indicator as well.

TM #5:
Pictured is the OEM AT1 & CT1 Yamaha crankcase assembly tool. It resembles the large bearing tool but has a partially hollow handle. It came with two threaded rods. One rod screwed into the internal threads of the left crank half of the AT1. The other rod had a coupler which screwed onto the external threads of the left crank half of Enduros equipped with a magneto. Once the appropriate rod was secured, the outside bolt was turned. This drew the left side crankcase half onto the left crank arm smoothly, and was removed when the crank case halves were securely mated. The spacer (indicated in the photo) acted to prevent the bearing from being pulled out during the process and to provide a uniform surface for the face of the tool to bear upon.

Because of the scarcity (I have never seen one) of the Yamaha OEM crank assembly tool, here is a home-spun version of the factory tool. I thought it best to post it here, where it would be more pertinent. Most crankcase halves should be able to be reassembled without too much effort, or use of this tool. However, having the tool allows the crankcase halves to be drawn together in a smooth, progressive motion (so long as the locator pins & transmission shafts line up & seat in their respective places). It also helps you to guide the rear side of the case halves while the tool draws them together on the forward end. A few particulars are worth mentioning:

1. Backing plate can be just about any diameter, but optimum measures 5.100
inches. Center hole should be at least 1 inch (pictured 1.100 inch).

2. I used a preexisting steel rod measuring .320 inch. It may be easier to
buy a already threaded rod & adapt it to fit your coupler. You only need
the second rod w/out coupler if you are working on an AT w/electric start.

3. The coupler should be drilled out to about 1.250 inch deep. You will need a
12mm x 1.25 metric tap to thread it. If you want to make the AT rod, one end
will have to be turned down to .270 inch & threaded for appx. 1.250 inch
using a 7mm x 1.00 metric threading die. On both examples pictured, the
opposite ends of the .320 rod was turned down to .300 & threaded with a
5/16 x 24 SAE die to accommodate the adjusting nuts. To attach the
coupler I bored a hole about .500 deep into it, inserted the rod, drilled two
holes thru both, & inserted a pair of steel roll pins to secure them together.

4. The handle can be made from any hollow piece of pipe, etc. However, the
thru-hole should be a minimum of .750 inch @ the end facing the crank. I
inserted a steel guide in the opposite end about 1.500 inch long, & drilled
out to accommodate the .320 rod. This is the surface the nut must bear
upon to draw the tool/case halves together as you turn it. All that remains
is to file or machine two small flats 180 degrees apart on either the rod(s)
and/or coupler, so you can use a wrench to tighten them onto the left
crank.

Addendum to above:
This tool can also be used to reinstall a completely removed crank. You would use the tool on the right crankcase to draw the crank/bearing into place. However, this requires a second coupler like the one made for the magneto. The additional coupler is needed because the threads on right crank half are 12mm x 1.00 (instead of 12mm x 1.25 for the left crank half). A small, round backing plate might be needed as well, with a clearance hole of the same dimension as for the left sidecase plate. Necessity is, indeed, the "Mother of Invention".!

TM #6:

Metric/SAE thread chaser kit. Very useful when dressing out or salvaging screws or bolts. This is what I turn to first when the need arises. In the event the threads require more attention, use of a tap & die set may be required.

Seal-puller. Basically a slide hammer with 4-jaw prong which opens up as you tighten it. No help with small oil seals but probably good for larger ones.