TTR400 manual cam chain adjuster bolt. The CB350F/CB400F has a weak point and that's the cam chain system and it's adjusters, this adjuster bolt is meant to help make the system a little bit better.
This bolt enables you to manually adjust the cam chain tension on the bikes listed below. The stock bolt (90016-286-000) is no longer used to adjust the cam chain tension. Leave it in place but just loosen it so it doesn't touch the push rod, then tighten the nut. This adjuster replaces the upper bolt that covers the springs and push rod.
This part consists of a blanking plug and copper washer with an M5 through hole, the M5 bolt and nut with copper washer is turned until the bolt contacts the push rod. Do not overtighten the adjuster against the push rod, it is normal for there to be some cam chain noise but it shouldn't rattle. Tighten the adjuster little by little until the desired cam chain sound is achieved, be careful and use good judgement. This will not fix a seized adjuster or push rod.
If you can hear your chain making a rattle, then screw in the M5 screw (8mm spanner) until you can hear the sound from the chain change. or rattle gets quieter. If you over-tighten you will hear a whine from the engine.....back off the screw.
Note: This is not meant to fix a seized adjuster horseshoe (14500-333-020) or a seized push rod (14550-333-000).
TTR400 part number: 400-007
Replaces Honda OEM part number: 25911-500-000
CB350F - 1972-1974
CB360K - 1974
CB360G - 1974
CB360T - 1975-1976
CJ360T - 1976-1977
CL360K Scrambler - 1974-1975
CB400F - 1975-1977