I have an '07 Roadie that I installed Roadhouse 66 slip-ons last riding season it seemed to run ok with the carb stock jetting with a few minor issues but barely noticeable. My wife got me a big air type air cleaner assembly for christmas . It's a big aluminum tube with the arrow type open air cleaner. After I installed it I started up the bike and it would barely run,idled ok but no throttle response. At this point I assumed I needed to rejet my carb. I purchased the Cobra Stage One kit (# 92-2272). I put in the 175 main jet and set the fuel needle e-clip on the forth groove as per the directions.I set the mixture screw at 2 1/2 turns out. It finaly quit raining here and was not freezing temps out so I roled out my bike and fired it up . Started right up,idled great and away I went. Idles perfect but has no throttle response for the first quarter of the throttle, total flat spot. If you crank the throttle it goes like a stripped ass ape! If you keep it in the upper RPM's it runs great. It has a huge power increase compaired to stock. So I continued on my ride anyway and rode about 50 miles. When I got home I noticed that there is now a discolored spot on the slip-on part of the pipe on the rear cylinder about a foot up from the back of the pipe and the slip-ons are double walled(HOT!). When I got home I left it running and turned in the mixture screw about a turn and a half in and road it around the block it seemed to help a little but not much .What do I do now ? HELP !!!

Bump.

http://roadstarclinic.com/content/view/63/96/

This may help. Most on here use Barons carb kits as their easier to get adjusted.
You might also want to go to the introduction thread and introduce yourself. Good people here and a wealth of information.

Did that jet kit recommend a bigger pilot jet? Sounds like that is where you are running lean. Try a # 40 pilot jet and I'll bet your problem will go away. When I was running my stock carb I used a speedstar kit and it required a change in the pilot jet. I used a # 45 and I used a 180 main jet with the needle on the 4th groove and it run great. It is not the same as when jetting with a Barons kit. BTW

This is what have on my yamaha road star 1700 i am making in to a trike.
When modifying intake, filter will mount a air/fuel gauge to hit it right.

cobra jet kits are the same as dynojet kits as far as measurement are concerned.

a 175 cobra/dynojet main is the same as a 163 mikuni main.

when you crack the throttle, you´re getting a squirt from the accel pump and enriching the mixture, hence your get up and go.

try the next size up main in the kit and put the needle on position 3 from the blunt end. from there you should be able to get it nailed just using needle adjustment

davej wrote:
Did that jet kit recommend a bigger pilot jet? Sounds like that is where you are running lean. Try a # 40 pilot jet and I'll bet your problem will go away. When I was running my stock carb I used a speedstar kit and it required a change in the pilot jet. I used a # 45 and I used a 180 main jet with the needle on the 4th groove and it run great. It is not the same as when jetting with a Barons kit. BTW

+1 on this.
The carbs have an overlap between the circuits(primary, midrange, main)
In that idle to 1/4 throttle, your not getting the fuel up through the pilot circuit that you need. The carb is drawing fuel primarily by vacuum at this point, because the throttle plate at the back of the carb, is mostly closed.
When you get past the 1/4 point, and the plate opens up enough for the carb to convert to the venturi action to provide fuel for the motor, your pulling fuel up through the main circuit. When your not relying on the pilot jet for fuel anymore, then your bike runs better.

However, due to the overlap, and the fact that at a normal cruise, the bike doesn't have alot of throttle( right at about a 1/4 throttle), it reverts to trying to pull fuel from the pilot, and it isn't getting enough. Therefore, your seeing the lean indicator on your pipes.

You'll get some more ideas. It's a big weekend, and lots of folks are away from their computers. The pilot jet's an easy fix, and can be done with the carb on the bike.

SKWEARpeg wrote:
The pilot jet's an easy fix, and can be done with the carb on the bike.

unless the float bowl screws have been replaced with allen screws, i wouldn´t reccommend trying this.

J.I.S heads and a philips screwdriver + limited access could result in carb off anyway and arsing about with a dremmell on shagged screw heads.

for what it's worth after you play with it and get it pretty close i would recommend finding some one to dyno tune it for you. i did my pipes a big air kit and a dyna 3000 ignition thought i was good to go. took it to a shop with real engine builders (not a stealer ship) and had them finish tune it. the guy got me 4hp and 5ft/lbs more and my mileage improved from about 36 to 42mpg! it took me about 3 hr's on line to find places and about 6 calls to get someone that would do a road star (most were just doing Harley's). then first time i could get was like a month out but it was all worth it and i sware by it now.

by the way...