SOHC.co.uk Forums > CB350/400
My 1975 CB400F restoration project
ozzybud:
The P.O. of this bike said he put a re-jetting kit in. He said it included instructions to drill extra holes in the exhaust, Throw away the air cleaner cover and new Main Jets and likely messed with the factory needle Position. ( I cringed a lot when he told me of this) Why didn't Honda think of this?
I rode the bike prior to tearing it down just to do some test and tune and make sure the engine was solid.(about 100 miles) It ran great pulled hard and had equal compression in all 4 cylinders.The carbs did not require synchronization. Plugs 1,2,3 were dark tan #4 was light tan.
The only changes i have made to affect engine performance was install the repro exhaust.
Took it for a longer ride yesterday about 10 miles. ran great at first after 5 miles it started missing on some cylinders. when i got home # 1 was coldish.
removed the plugs 1,2,3 were black and sooty fouled or on there way to fouling.#4 was fine
I removed and cleaned the plugs. All of the idle mixture screws were out 4-5 turns? what? almost ready to fall out... lol Reset to 1.5 turns out.
Took it out today with similar results ran good a little longer.like 7 miles. removed the plugs and they looked similar.
I am assuming at this point that the P.O. removed the #75 jets for something larger. I ordered 4 OEM Used #75 jets and a gasket o-ring set.
I will Check out everything else when i get the carbs off.
Is there anything else I am missing? I spent a lot of time on my CB360 getting it to stop fouling plugs. It ended up being the Chinese needles were smaller diameter and a little bit shorter than oem.
Any suggestion would be appreciated.
McCabe-Thiele (Ted):
Have you checked the condition of the coil leads?
davidcumbria:
I suggest you have a read through some of the posts by fogrider. He put a sensor in the exhaust of a 4 into 1 and discovered all kinds of things about the fuelling. Several people have found aftermarket needle jets and seats have been the source of their problems.
Johnwebley:
While the carbs are off, worthwhile to check the float heights,
Sent from my SM-A546E using Tapatalk
McCabe-Thiele (Ted):
Your photo had me confused (I'm easily confused) - is it a close up of the old silencer end?
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