| Also known as | 70-4603, 70.4603 |
| Diagram | Fig. 5 — CYLINDER BLOCK AND HEAD TR7RV · ref 16 |
| Listed in parts books | 1964–1965, 1967–1968, 1970–1971, 1974, 1976–1980, 1985 |
VALVE,INLET PLASMA HARDEN
Plasma-hardened inlet valve, PN 70-4603/SRM, for unit-construction Triumph twin cylinder heads.
70-4603/SRM is an inlet valve for the unit-construction Triumph twins, plasma hardened at the seat and stem area to hold up under valve-train wear. It's the standard-diameter intake valve fitted in the head, controlling the flow of the fuel/air charge into the cylinder on the intake stroke. The plasma-harden treatment is called out right in the part name — it's a durability process applied to the valve, not a coating you'd need to reapply.
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You'll also see this listed under the shorter forms 70-4603 and 70.4603, which are the same physical part. Catalog and figure detail on this one is thin in our records, so if you're matching it against a specific head, check the number stamped on your old valve or your parts book listing before you order to make sure it's the right one for what you're rebuilding.
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