Re: Cx500 minor bob job - Now it runs
I'm jetting a CX500 in my shop right now. I am keeping the airbox, but I modified it. There is a rubber snorkel where the air enters the box. It's there mostly to reduce intake noise. I removed it. Inside the box is an aluminum perforated plate covered with fine mesh. I assume that it's there as a flame arrestor, but it clearly adds substantial restriction to flow. I yanked that out. Lastly, I replaced the filter with a K&N. These three changes will require substantial jetting changes.
I increased the main jet from 78 to 90, and the intermediate jet from 115 to 120.
I still have to adjust the valves, sync the carbs, and adjust the idle mixture. The bike seems waay too lean to me yet, but it's a little hard to tell with an ambient temperature of 25F! After I ran it for a while yesterday, I got a compression reading on warm engine of only 60-70 psi. I may try another Seafoam treatment, and run it a bit to see if it improves. I'm hoping that adjusting the valves will help it, too. If I don't get the compression up to at least 125 psi, a ring job is in this bike's future.
Since you plan to keep your airbox, I'll let you know what I end up with for jetting, as you will probably want to make the same airbox modifications that I did.
Anyone have jetting recommendations for me here?