Author Topic: CB500 Carb Jetting  (Read 1426 times)

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Offline EROCK

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CB500 Carb Jetting
« on: November 08, 2015, 07:45:32 AM »
Hello All,

So I'm finishing up my CB500 build.
I have a new 4 into 1 megaphone MAC header with UNI pods.
If I want, what size jets should I change to maximize performance..?

Thanks, Erock
So many bikes and so little time.....

Offline mrfish2

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Re: CB500 Carb Jetting
« Reply #1 on: November 08, 2015, 09:02:45 AM »
If you still had the stock air box on there then the MAC system doesn't usually require any jetting changes, but pods are a completely different story. I don't think there is a general consensus about jetting with pods (besides a bigger main jet), you're just gonna have to start with stock jetting and do A LOT of plugs chops to get it dialed in.
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Offline DaveBarbier

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Re: CB500 Carb Jetting
« Reply #2 on: November 09, 2015, 04:57:20 AM »
Some members might chime in with what they're running with a similar setup. This could give you a starting point but as mrfish says, you'll need to do plug chops (or dyno runs :)) to get it dialed in .

Also, this isn't a matter of deciding to change jets to maximize performance. You'll need to rejet to get your bike to run right.

What are your stock jet sizes and was the original exhaust a 4-4?

Offline jonda500

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Re: CB500 Carb Jetting
« Reply #3 on: November 09, 2015, 06:01:26 AM »
^ I agree with Dave- you wont be aiming to "maximize performance", it's more likely that you will be struggling to get it to be vaguely ridable and not fouling plugs. A more realistic goal would be to achieve good full throttle performance and to minimize the inevitable flat spots at smaller throttle openings.
The stock set up runs well not just due to the correct jet sizes, needle clip settings and air screw settings, but also because of having the correct needle tapers, emulsion tubes and slide cutaways! The first three are relatively easy things to change...........
Good luck anyway - dont let me put you off, be patient and persistant!
John
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Offline bochnak

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Re: CB500 Carb Jetting
« Reply #4 on: November 10, 2015, 03:44:17 AM »
I have found the following to work well when working on a bike with pods and exhaust:

One step leaner on pilot jet (air screw will probably fall at 3/4 turn out)
Raise needle (lower clip) one position
Bump mains anywhere from 2-4 sizes larger

Here are some blog posts and videos that will help you out:

https://www.howtomotorcyclerepair.com/cb400f-jetting-test-spin/

 https://www.howtomotorcyclerepair.com/how-to-tune-a-motorcycle-main-jet/