Carb drain tube

I went ahead and put the 15 tooth back on to make sure it was the rev limiter I was hitting. Turns out it wasn't. My quad still starts to cut out at in 5th gear when I am really on the gas (full throttle) Like I said before I have had this quad for about 7 months and I bought it with WB R4 exhaust. The guy I bought it from jetted it already and I haven't had any problems with anything like this before. The jetting is correct I am sure of it. The plug looks good not too black just right. I think their might be something in the carb some dirt or something that every now and then blocks the jet(S). I am going to unscrew the carb drain and see what comes out. I had the whole carb out before, but I couldn't figure how to unhook the throttle cable. I did re-route the drain tube is it possible that the fuel cannot drain fast enough out of the bowl? I checked to make sure I didn't pinch the tube and the fuel does come out like normal, but maybe it can't come out as fast now that I re routed it. Anyone have any other ideas? I am sure it is getting plenty of air (intake wise) I can't think of anything else that might be causing this? Can someone explain the purpose of the drain tube? Does it just dump out the extra fuel the carb doesn't need, at fuel throttle? Anyone recommend just a carb clean with compressed air? Anyone use carb cleaner in a spray can? Any help would be great. Also does Cyclmer make 2000 400EX shop books or do you have to buy the one from Honda?

[Stunz]

The drain tube is just that, a drain for the fuel bowl. It's there so when you open the bowl drain screw, you can catch the gas in a jar (instead of dumping gas on the bike). It doesn't matter how you route this tube. You can actually take this tube off (not recommended).

The other tube that leaves the carb is the vent for the carb. This is the tube that can not get pinched.



What Main Jet is in it?
What clip position are you at on the neadle?

I don't know what jet I have in or what needle clip position its on. I never had to jet it becuase I bought it jetted. I don't think it has anything to do with the jets or neddle clip because I have rode this quad like this since day one and never had any problems at full throttle this just started. I will tkae it apart and see what jets are in it. I guess I need to know anyways.

[Zero Z400]

I don't know how to help with your problem. But, the carb cleaner in a can is great, you might want to clean it, no good reason to but still a good thing to do every once in awhile. An air compressor won't do the same thing. Gumout(carb cleaner) breaks down all the build up or other stuff. Try taking your carb apart, clean a mess with the clip position.


Later

yeah, the carb might be dirty. I have also heard of the main jet unscrewing itself, and it won't work right at full throttle(3/4-full) maybe it's electricial too, but I don't know what to tell you about that, just make sure the wire connections are tight.

[Deathbringer]

I have a question..?? Is it cutting out or blubbering??? Also if you are going to tear it apart, mark down what jet size it is and where the clip position is.

145,main 38 piolt--stock needle position

[Stunz]

Your bike was never jetted and you do not have a "race" pipe.
The R4 is just a slip on.

The 145 is to lean. Stock 400's came with 148 Mains and a few with 145's.

If you run a lid, go with a 150-152 Main Jet.
If you take the lid off or cut holes in it, go with a 155-158 Main Jet.

Its not a slip on its a complete exhaust it might not be a race pipe, but It is a complete exhaust kit pipe and silencer. Thanks for your help.