Hi, I did a lot of searching first but didn’t find an answer and am hoping someone can help me.

I recently bought a 300ex 2000. It had a carb from a 350 on it. It also came with the stock carb. The carbs are not exactly the same and since I am putting it back to stock I wanted to go with the stock carb. It ran OK? for the most part but a little rough with the 350 carb. I put new stock jets and pilots in the stock carb, made sure everything was clean and functioning properly and the air idle screw is out about 2 turns.

It runs like total crap. I have to hold half throttle for it to even run and then when it does it choughs and chokes a lot. I tried different air mixture screw setting less and more and it didn’t seem to make any or little difference.

The needle looks good. I changed the setting on the clip 1 up, one down and the middle with no change. Pulled it off SEVERAL times and made sure everything was clean and working.

Any ideas? Please!

 

maybe the timing is off? doubtful, but worth a try

I would check to make sure the choke is working properly. If it wont run below half throttle, it sounds like too much gas is getting in, and you have to open the carb (more air) to compensate to get a burnable mixture. I dont know about the 300ex, but it might have a vacuum carb? in that case, make sure your carb piston is bouncing a little when running, you can see it from the air filter end, if it has one. I dont knwo much about those machines, but nobody else responded to your thread so i figured i'd help out with what i could.

i'm not calling you stupid or anything, but make sure all jets are stock size and jet needle is in the stock clip position, also maybe get a manual and see if that pilot screw is set right. also, if there are any vaccuum lines going to the carb, make sure those are on.

might want to check the FLOAT LEVEL too, too high of float level will make it run rich too. You'll need a manual for that too. If you plan on keeping the bike, might want to get a manual anyways.

 

Sorry, but did you read my post? Works pretty good with one carb but the not the other one? Only difference made has been changing carbs. Oh, and TIMING??? Vacuum lines going to the carb??? What kind of quad do you have?[img]i/expressions/face-icon-small-confused.gif[/img] Dude, you may be trying to help but have you ever really worked on one before or just looked at it? For 99% of the stuff I would never need a manual. Maybe for torque specs and tolerances/clearance for piston to wall, crank and bearing questions.

Everything is put together right. I have 2 carbs that are 99.9% identical. I have both apart MANY times and everything is the same and clean. Everything works freely and smooth.

I do have a little experience with carbs on ATV unfortunately. I have had my dual carb setup apart to many times on my Raptor playing with it's jetting dialed in so I do have experience and am very mechanically inclined. I'm just hoping maybe someone with experience with the 300ex has had a similar problem and could share the solution.

Please no more shoot from the hip answers with 0 experience and not even reading what I wrote first...Timing?[img]i/expressions/face-icon-small-blush.gif[/img] The float level is not a bad ideal though and I will have to double check that. Thanks for posting though and giving it a shoot.

 

I guess everyone is off on one last fling before school starts [img]i/expressions/face-icon-small-sad.gif[/img]

 

Recheck your carb linkage timing against the service manual.

 

Hey, I have a perfectly functioning 300ex stock carb. If you want to figure a way, you can see if it is that carb. If it fixes the problem, I'll sell it for CHEAP. I drive to MV, for work on a frequent basis....

 

Got my carb today. Works great. I havent taken it for a ride yet but it runs and idles better than ever so far. I still nee the stock baffle though [img]i/expressions/face-icon-small-sad.gif[/img] I will probably just end up buying a stock muffler of ebay since no one seems to want to part with the baffle they took out and probably will never use again.[img]i/expressions/face-icon-small-disgusted.gif[/img]