Hey, question. I put a bigger carb on my scrambler 400 , a 38 mm mikuni flatslide. Is there anything I should watch for when putting it on and running it besides the jetting. I dont want to break my jug or engine case again. I broke it after riding about 30 minutes with the new carb on. Im not sure it had anything to do with the carb but !!!!! the piston, rod, berings and crank were okay.

 

Just keep an eye on your midrange and do some plug checks and you should be ok.

 

i have a 38mm TMX flatside on my 400 and have not had any problems. the jetting i use is 390 main jet, 35 pilot and clip in middle of stem with modifiied factory air box and uni air filter. i have the air screw about 1.5 turns out but when the turns cold ( like it just did this week) i will do some plug checks and usually i have to turn the air screw to 1 turn out.
later
hunt

 

Thanks, that will help alot. I was told the mid range was weak, what can I do to help that. Also what altitude are you running. we are about 3000 feet.

 

Not sure about attitude but i live about 45 miles northeast of Paducah, KY which is in western KY along the Ohio river. I'm using a heelclicker clutch kit and don't have any problems with the mid range- it's set to the scramber settings. If you plan the head about 0.020" it will wake it up. Mine is currently heavyly modified and is very strong from bottom up.
later
hunt