Claviger
Aspiring Student
- Joined
- Jul 25, 2014
- Messages
- 6,934
- Location
- Olympia Washington
- Ride
- '21 Z H2, '14 R3R, '02 Daytona 955i
2 plugs per cylinder. Big cylinders. Low specific output. Hotter plug helps fire it off correctly and if a plug is too cold it won't clean off properly and can over time build up excess carbon, 7s make sense. 8s, anecdotally work just fine so, use whatever on a stock engine bike, doesn't seem to matter.
8s were likely a lazy holdover because that's what almost all the Triumph's of the era used. Makes stocking them easier for dealer network.
7 vs 8, shouldn't run any different, 7s should burn off contaminants more readily. Generally you want to run the hottest plug you can that doesn't cause ping/predetonation as it helps conduct heat out of the chamber and into the head more readily.
I runs 9s as well, as a precaution.
As a very broad for NA guideline every ~50hp+ should be 1 range colder, but that's just where you should start. Then inspect the plug after running it for a bit and see where the strap mark and porcelain burn ring is located. Adjust accordingly.
Boost and nitrous have very different needs and at high boost (30+) and big nitrous shots, plugs become a consumable and you run what you need to lite off the mix and limit detonation more with ignition timing.
8s were likely a lazy holdover because that's what almost all the Triumph's of the era used. Makes stocking them easier for dealer network.
7 vs 8, shouldn't run any different, 7s should burn off contaminants more readily. Generally you want to run the hottest plug you can that doesn't cause ping/predetonation as it helps conduct heat out of the chamber and into the head more readily.
I runs 9s as well, as a precaution.
As a very broad for NA guideline every ~50hp+ should be 1 range colder, but that's just where you should start. Then inspect the plug after running it for a bit and see where the strap mark and porcelain burn ring is located. Adjust accordingly.
Boost and nitrous have very different needs and at high boost (30+) and big nitrous shots, plugs become a consumable and you run what you need to lite off the mix and limit detonation more with ignition timing.