G'day guys. I had a lot of popping problems while using the W/B pipe. We tried lots of ideas mostly from you guys & gary's message board. Nothing helped, the popping came in @ about 6000rpm, so I knew it was NOT the rev limiter.
I just had to prove it to the bike shop . They spoke to polaris who said to put the original pipe on untill they get a jetting kit from USA. Hope it's the Airforce. The Pred now flies [img]i/expressions/face-icon-small-smile.gif[/img] and to now have all the 9ooo odd rpm to use is awesome.

2 ideas I would like to suggest
1. Get a tacho and you will find out that if it starts to pop before 9000rpm it is NOT the rev limiter, it's your exhaust/jet setup.
2. Put your original pipe on and you will here this girl sing.
Short shifting is treating the symptons and not the cause.

Thanks from down under Geoff.

 

not to sound like a nut but where is Geelong??

 

Australia[img]i/expressions/face-icon-small-smile.gif[/img]

 

So the popping is fixed - but now it is stock? I want mine fixed without being stock, I know stock works.

 

Thanks aussiequadrider!
COOL!
-MT

 

Anyone considering replacing the CV carb with an FCR? I really think this is the way to go if your going to modify. When the warranty is up I'm planning to switch.

 

Aussie- I am still not sold on that Air Force kit. I would like to see a stock dyno against it instead of the WB slip on. We all know that the WB slip on was cuasing a lot of problems and a loss of power. Lets see stock against the kit and then we will see how it performs. If you look at the dyno on his page it gets real jumpy at around 7000 is that because it is starting to stumple? With the WB slip on it stumbled there also. Seems odd?Look at HMF's dyno with their slip on and the stock airbox setup. They get good increases and a smooth power, big torque increase as well. They also show it compared to stock. No stumbles anywhere.

I think Polaris really did their homework and set it up correct right out of the box. FCR Carb may be the way to go if you are going to change airbox mods

 

Hello, can you share alittle more about this FCR Carb, is it a Mikuni or Kiehin or what? Anywhere on the web I can take a look at it? thx, Putt

 

Keihin has the FCR, it is a racing carb not a CV. Many people are using them on modded EX's. 39 and 41mm are the popular sizes, they are a flat slide with an adjustable accellerator pump. Go to Keihins home page and look in the offroad section for more detailed info. Curtis Sparks sells them as I'm sure others also.

 

The FCR is a kicka$$ carb. I had a 35mm on my 250x when it was around 273cc, but I went with the 39 when I built it to a 352 and it still works great on my 410x. Easy to go to alky. Take time, lots of time to tune properly, but is untouchable when set up right. It is a flatslide like was said, but is so well designed that the slide even has rollers on it! It is designed for racing, hense the reason it has no choke. I haven't really needed a choke though even on alky.

BY the way, the DRZ dirtbike (what the Z400 engine was pulled from) runs a FCR. The Z runs a CV style though.

CV (constant velocity) carbs work off of engine vacumn. The idea is just to let the engine pull the air/fuel that it needs. When stock, there is just the right amount of vacumn to overcome the slide spring. When you cam one (or open up exhaust restriction to a point) you change the amount of vacumn which will restrict the opening of your carb (because it will open the slide too soon or not enough) .