Topic: Carb setup for a 1974 cb550 in Denver

[sipesracing]

Do you guys have a basic setup for a 1974 cb550 .I am running no airbox and I am going to be installing a 4-1 exhaust .These carbs are equipped with push in style jets that and they are hard to find and pilot jets too .Should I just find another set of carbs and upgrade those and what year has more adjustabuility or should I say screw in style mains that are easy to find... I was told that for my setup I should start with a 90 main and 32 pilotand 2 turns on the sirfuel screw. What do you think...

[Jerry Rxman Griffin aka MuthaF'er]

What are the stock sizes? No air box and header, probably 2 size bump for starters HOWEVER 5280 would decrease the stock jet size. Put the 4 into 1 on and see how the stock jets do first. The altitude might cancel out the need to increase. Make sure your carbs and jets are clean and synchronized first. Proper tuning a must to set carbs! Fresh plugs for better performance and easier to "read". Then don't run it long without checking your plug readings. I don't know of anyone in our group with a modified 500/550 near here.

I'm at 6850. I'm running 2 sizes over stock BUT I also have a 812, cam, and Kerker with stock airbox and K & N filter. It's a bit on the steep/rich side but it sure runs nice when I crank it. Won't take a lot more elevation though without getting really rich.

[Gordon]

On my '76 550K with stock exhaust, and stock air box with foam air filter, I'm running the stock jets and have had no issues with plugs fouling. 

[Duke McDukiedook]

Like Jerry said try it out stock with your 4-1 pipes on and see how it runs. Then make your adjustments accordingly. Keep the airscrew at stock settings also in the beginning, the altitude may cancel out having to go smaller in jet size.

[moham]

Do you guys have a basic setup for a 1974 cb550 .I am running no airbox and I am going to be installing a 4-1 exhaust .These carbs are equipped with push in style jets that and they are hard to find and pilot jets too .Should I just find another set of carbs and upgrade those and what year has more adjustabuility or should I say screw in style mains that are easy to find... I was told that for my setup I should start with a 90 main and 32 pilotand 2 turns on the sirfuel screw. What do you think...

I don't know who told you jets are hard to find buy they are mistaken. You can easily find everything you need to rebuild 74 550 carbs.

[CU2151]

I'm in Boulder and have 4-1 on my otherwise stock 550 and she runs just fine with stock jets.  I also recommend trying out stock jets before tinkering.  It can be hard to find the right setup once you start messing with everything.