| Also known as | 70-4778R, E4778 |
| Diagram | Fig. 13 — MOTOR FITTINGS · ref 18 |
| Subsystem | exhaust |
| Listed in parts books | 1964–1970, 1974 |
Engine torque stay
A steel engine torque stay that anchors the top of the unit-construction engine to the frame to control motor movement.
The 70-4778 is a torque stay that ties the top of the engine unit back to the frame, keeping the motor from flexing under load. It shows up in the parts books under the fittings and exhaust-system figures, which puts it in the group of small brackets and stays that hold the engine steady and keep the exhaust system aligned as the bike runs.
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You'll also see this part numbered E4778 or 70-4778R in older records — same physical stay, just a different catalog listing from another point in the run. It's a plain steel piece finished black, the kind of bracket that's easy to overlook until it's missing or cracked and the motor starts moving around more than it should.
Our records show this stay appearing across a long production run, so a lot of the unit-construction Triumph twins used some version of it. Confirm how many your particular engine calls for and how it bolts up before you order, since the mounting count isn't something we can pin down from the catalog entry alone.
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