Low and Midrange issues

[Redneckrider]

I have a 2004 XL883 that I just put a Wiseco 10:1 1200 conversion kit on. I haven't changed anything else on the bike. I did place a #10 brass washer under the needle for that little extra....top end is fine and she has plenty of oomph in fifth gear, however, the first 4 gears it just doesnt seem to run right. It runs a little rich, but only the rear plug only shows fouling. This is my first time ever doing anything like this so I'm at the limit of my knowledge. I have 170 lbs compression. I just can't figure out why in the lower gears it just doesnt want to run quite right. Its hard to explain what it does. I know that I have reached the limits of my patience with this and need some expertise help or at least someone that knows more than me.

[andyxlh]

Hello mate
I sure don't now more than you, but I have had a similar issue when one of my inlet manifold seals was bad. It leaked a little on the front making that one lean, it wouldn't run well except for flat out and the rear plug fouled as most of the fuel went that way. BUT that happened because the seals were 10+ years old at the time and bad. Probably not your issue but you never know as they have been disturbed.
If you are running a stock carby and it is anything like mine on my '89 model you would need to rejet it for the 1200, especially if you opened it up a lot with new air filter and pipes etc too. I would have thought that shimming the needle would change the fuel profile over a certain rev range, but if you still have the old jet in perhaps you a re not running rich in the lower RPM? I havent shimmed my needle but rejetted with no problems and no flat spots many years ago. I went with a 45 idle and a 180 main and that seems to work wiht my engine with head mods and cams too.
sorry not much help but just a few thoughts!
Andy