XR400R Sudco carb??

[fergy2]

Anyone familiar with the aftermarket Mikuni "Sudco" carb? I've got one on a 02 XR400R and can't seem to keep it running smoothly. When I excelerate into 2nd, the bike seems to want to cough (as if it was running on vapors).

The bikes been improperly stored (by the previous owner) for the last 12 months (fuel not removed). I've flushed the tank, replaced the fuel, installed new plug, drained carb and still no improvement. I guess my next step will be to remove the carb and do a through cleaning. Not too sure at this point if its a "gummed-up" carb or the carb itself.

Any suggestions/recommendation are appreciated.

thanks,

fergy

[drtbkr]

My Pumper took all the coughing away. I think taking the carb off and doing a thorough cleaning will get it back into shape. As a rule, I always turn the petcock off while the engine is running after I get done with a ride. Gets all the gas in the carb burned up so it doesn't sit and varnish.

[ohioxr400]

Mikuni pumper carbs r not like edelbroks. the mikunis have to be jeted justlike a traditional carb. Sudco jets the carbs and sends them out. For some reason when i bought my carb from sudco it was jetted really lean. I had to change the neddle jet from a 12 to a 16. When i did this all the problems went away. Trying changing hte jetting.

[fergy2]

Took the advise and removed and cleaned out the internals of the Sudco carb. I was hoping to see deposites within the carb body (hoping it would explain the rough idle, stumble and coughing)but no luck. Internals look clean although I did disassemble, clean and reassembly body and reinstalled. In my haste to reassemble, I damaged the o-ring between the head and the rubber manifold. This I'll ahve to order from Honda. I did try to start it up and it ran even worse. If this is not related to the o-ring, I'll be in the market for a used 02 Xr400 stock carb and "shelf" the Sudco.

fergy

[KEVXR416]

fergy,

I have a 02 stock carb sitting on my shelf in the garage PM me if ya want to make an offer ?