New 650R mods installed and have problems

[JRWYW]

My brother just installed a Power-Up kit and a Big Gun Race exhaust system. He rejetted to a 178 main provided by baja designs. When he restarted the bike it was backfiring just above idle and on deceleration. It also has a dead spot at 1/4 throttle where it will buck/jump/miss, and then it will hesitate reving to WOT from that point. He changed the pilot jet from a 65s to a 68s and he said it seemed to help. He also turned the idle air screw out to 2 3/4 turns and said that it was a little better but any further and it made it worse.

I think he needs to go richer on the pilot. What do you guys think?

 

[OnAnySunday]

The 68s should be fine.
Did he change the needle?
Also did he change the rubber intake manifold?
and remove BOTH of the airbox restrictors?
I admit i forgot to remove both of mine at first.......heh heh. :laugh:
Backfiring though? hmmmm. :think:
Sounds like something other than carb., but im a sucky mechanic so .......?

You ought to check out the XR650R group at yahoo.com.
They have all sorts of great info on BRP's.
From jetting to suspention....etc...etc.

 

[JRWYW]

He got a new needle and the clip is in the middle. He removed all the crap from the airbox and installed a new intake. I don't think he tried the 175, but I'll ask. The plug looks a grayish color. He's running at about 1000-4000 FT between 50-80 degrees. He Says the bike runs like a raped ape at WOT, but it has a dead spot when you first crack it open, and pops when you let off. Since he went to a richer pilot and it helped, I figured a even bigger pilot would help more. However I know bigger is now always better.

 

[hurricane jonny]

GET THE EDELBROCK CARBURATOR. It will make all the differance in the world. I wouldn't have gone with the gun exhaust either. The stock muffler with the HRC tip is the hot ticket