I just got a new Powercore 2 for my 03 KX250. I have an FMF Gnarly pipe on it right now. I rode it today and its sacking out when I go wide open, its also popping after the sacking. It has never done this before. I know I had to rejet my bike when I put the Gnarly pipe on but do I have to rejet my bike for the new slip on muffler? has anyone ever had to do this? My bike was running great before I got this new exhaust.... Im in Montana at around 3000 feet in elevation. Please help me out guys!!!!
Rejetting for new Powercore 2????
- Thread starter AdamRides87
- Start date
I heard that aftermarket exhaust has more air flow to the motor making breathing easier. Since I'm getting more air do you think I should put in a larger jet then?Had to move the needle clip on the KDX200 when we put on the DG pipe and then re-jet when we put on the DG muffler. Once we had the full system on, she was lacking at wot. -BIG DAN
Symptoms are the way I judge jetting.
If it full bogs, it's lean.
If it burbles, it's rich.
In our case the needle needed to be leaned from the pipe addition, due to an off idle burble.
Then when we got the muffler on it, full bog at wot. She needed more fuel at wot so we went richer on the main jet. Off idle was still crisp, so we left it alone.
http://www.iwt.com.au/mikunicarb.htm
-BIG DAN
If it full bogs, it's lean.
If it burbles, it's rich.
In our case the needle needed to be leaned from the pipe addition, due to an off idle burble.
Then when we got the muffler on it, full bog at wot. She needed more fuel at wot so we went richer on the main jet. Off idle was still crisp, so we left it alone.
http://www.iwt.com.au/mikunicarb.htm
-BIG DAN
yeah it seems 0 to half throttle is fine, its idles great still. just when I whack the throttle it falls on its face. I pulled the brand new plug and it was drenched and black.... so it almost seems like it too rich, but that's odd cause everything I read and what you guys are saying is it should be leaner. I had a 165 main jet in it and 0 to half was crap, pulled it and put a 168 main in it and it was worse. 1/4 to WOT was crap. So I guess ill put 165 main back in and move the position of the needle?Symptoms are the way I judge jetting.
If it full bogs, it's lean.
If it burbles, it's rich.
In our case the needle needed to be leaned from the pipe addition, due to an off idle burble.
Then when we got the muffler on it, full bog at wot. She needed more fuel at wot so we went richer on the main jet. Off idle was still crisp, so we left it alone.
http://www.iwt.com.au/mikunicarb.htm
-BIG DAN
All the fuel circuits in the carburetor compile on each other. Work from the bottom up.
Start by setting the idle mixture first.
Then adjust the needle so 0-1/2 throttle is snappy.
Then adjust the main if holding it WOT give you anything but light speed acceleration.
It is completely possible to need to lean your jets with new pipe. More is not always better. -BIG DAN
Start by setting the idle mixture first.
Then adjust the needle so 0-1/2 throttle is snappy.
Then adjust the main if holding it WOT give you anything but light speed acceleration.
It is completely possible to need to lean your jets with new pipe. More is not always better. -BIG DAN
I really didn't think adding just a slip on would have such a big effect I jetted my bike for the gnarly pipe last year and thought I was done with this shit ha guess not...
