Topic: Suggest Jet size for 1976 Cb550 w/Cb650 cam/605/port os

[L.A. Nomad........]

This is for a friend, ball park main jet sizes for CB550 with mods.

1976 CB550:
CB650 cam
605 big bore
opened and clean intake ports
has velocity stacks w/screens
electronic ignition
4-1 exhaust

Too hard to find in search. He currently has 100 main jets now. What are your thoughts and he's keeping the velocity stacks.

Thanks Eddie

[L.A. Nomad........]

Almost forgot!

We are at sea level, L.A. area. I know we'll have to mess around with the needle position and adjust. I know we might even have to use jet files..

He's gonna make a parts order soon, just need a range to start off with. He's gonna buy a couple of sets. Any suggestions?

Eddie 

[bwaller]

Here's one mans experience...take it for what it's worth at 600 feet above sea level.

These are 77K PD carbs, originally with #42 pilots & 90 mains. Uses the stock plenum, no airbox, but a single large K&N filter.

Runs like a top with needle up one notch, 107.5 mains and with a tapered reamer enlarged pilot jet to #46 equivalent.

Good luck

[Will]

Have you gotten a good tune on this CB550 yet?
I am just finishing a similar build; 600cc, 650cam, ported intake, pods, 4-1 high flow exhaust.

I'd be interested to hear where you ended up for jetting and needle position.