Exhaus question I posted in reply to a post. Reposting fresh

I have a question on that, then. I have an xj550 maxim. I know its next to the baby of xj models, but its quick as hell and I am just attached to it. More than any bike I've ever had

Well, anyway... I just modded the carbs with K&N pods and rejetted to suit... actually a little more than needed. Went from 1.12 mains to 1.25.

The performance boost just from that is beyond what I expected but now I have to run it on PRI (prime) instead of "run". (referring to settings on the petcock) The vacuum system doesnt pull enough fuel in, otherwise. I am turning this into a rat bobber and I know I am way off in tradition here, but I am installing the Mac 4 into 1 exhaust instead of straights or baffled tips, etc. Hoping this will balance things out.
With this set up, what would you suggest if its different than what I am doing.

 

Re: Exhaus question I posted in reply to a post. Reposting f

Greetings...sounds fast!!!
1st thing I picked out of your post is that the fuel petcock needs to be rebuilt. Vacuum opens the valve and planty of fuel should gravity flow in the run position. If you have to operate the motor in the prime position then the valve or vacuum line is clogged.

 

Re: Exhaus question I posted in reply to a post. Reposting f

I was figuring that at first and really have bad luck with petcocks. Haha... I can adjust and replace valves, rebuilt and rejet carbs like a pro... as long as my trusty book is handy (keeps me from leaving things out, and do a lot of other things... but give me a petcock which a kid can rebuild and I'll ruin it for ya. I am thinking, since it ran great in the run position before my carb mods that I disrupted the vacuum. But I am tearing into it, and that includes a petcock job, over the winter. I do know from my old seca that the vacuum system and keeping everything balanced out can be a b***h with the xj motors. But they are so bad ass when they are tuned and running right