| Diagram | Fig. 4 — Engine: Contact Breaker, Timing Cover, Oil Pump, Oil Pressure Relief Valve · ref 41 |
| Subsystem | engine bottom |
| Listed in parts books | 1975 |
Norton Plunger
Oil pressure relief valve plunger, part number 06-6199, from the 1975 engine bottom-end lineup.
This is a plunger for the oil pressure relief valve, part number 06-6199. It shows up in the catalog under the engine bottom-end group, in the figures covering the contact breaker, timing cover, oil pump, and oil pressure relief valve area for the 1975 model year.
Read more
The relief valve plunger is the moving piece inside the pressure relief assembly - it sits against a spring and seat, and its job is to let oil bypass the system once pressure builds past what the valve is set to hold, protecting the oil pump and bearings from being over-pressured.
Our record on this one only ties it to the 1975 listing, and the catalog naming points to a Mk III relief valve application. If you're matching this to your bike, give us a call and we'll confirm fitment before you order.
Sorry if we got something wrong here. If you think this information isn't correct, .

