couple questions

[evan402]

Ok i just picked up my 400ex last friday. Traded my 1999 scrambler straight across- i wanted a light machine i couple whip around. Only problem the guy said was that it would foul the plug every other week, i assume its a carb issue. I bought a carb rebuild kit and i am doing that as i write this, jetting probably isnt correct either. he has stock jets but machine has outerwears with k&n and open box,powerbomb header and e series exhaust. Other question is when i got it home and checked it out further the left side rear wheel seems to wobble side to side...just from comparing each side of the axle i noticed the right side has a little metal spacer next to hub and the left does not, is this why it wobbles, as it seems it just isnt tightened all the way. or would it be bad bearings? i will try to take pictures of it tonight when i get home to better explain my issue. ANy thoughts?

[trailrider894]

Looks like nobody else is gonna pick this one up. Well, i'll help ya out!!!!!!!! :devil:

This one thing that doesn't make sense, he says it fouls the plugs... If your jetting is stock, it should be running lean not rich. I have VERY similar setup as you, i have the white bros e-series and powerbomb header with K&N with outerwears. Really i need more info on making any back firing or popping and cracking it is doing? is it hard to start? does it bog when you gas it real hard?

As far as your hub, it sounds like it is just loose on there. Mine gets that way sometimes i just tighten it back up and off i go. I would have to see a picture of this " spacer ", makes it sound like you might have an aftermarket axle that is extendable or the guy you bought it from was smoking crack. It could be your axle bearing, because the hub doesn't have bearings. Does the whole axle have play in it on that side? or just the hub? try lifting up the atv and messing with the axle to see if it has play, if it does then you need axle bearings. It is a common occurence on the 400ex to have to replace the axle bearings every once and awhile.

[sixer3]

What makes you think the jets are stock? also things to check for whenf ouling plugs is improper plug gap and make sure he is running the correct plug as well. Also make sure the choke works properly as this would cause you to foul plugs quite easily if the choke doesn't close/open properly.

On the hub first check your lug nuts, then yep make sure it sint your entire axle, then take the cotter pin out of that big castle nut and tighten it a bit on the hub then throw the cotter pin back in there (doesn't have to be extremely tight)

[trailrider894]

Originally posted by sixer3
What makes you think the jets are stock? also things to check for whenf ouling plugs is improper plug gap and make sure he is running the correct plug as well. Also make sure the choke works properly as this would cause you to foul plugs quite easily if the choke doesn't close/open properly.

On the hub first check your lug nuts, then yep make sure it sint your entire axle, then take the cotter pin out of that big castle nut and tighten it a bit on the hub then throw the cotter pin back in there (doesn't have to be extremely tight)

I tighten mine as hard as i can with my big socket set.

[sixer3]

Originally posted by trailrider894
I tighten mine as hard as i can with my big socket set.

Yeah it's funny, I've broken some liek that trying to keep it tight but have a hole for the cotter pin. Then I've left the cotter pin out, don't do this...I just find it best to have it as tight as possible but don't worry about over tightening it just to get the cotter pin in....oh and don't try and run it without the cotter pin :P

[CJM]

I just use my impact gun and give it a few good hits and put the cotter pin in.

[trailrider894]

Originally posted by sixer3
Yeah it's funny, I've broken some liek that trying to keep it tight but have a hole for the cotter pin. Then I've left the cotter pin out, don't do this...I just find it best to have it as tight as possible but don't worry about over tightening it just to get the cotter pin in....oh and don't try and run it without the cotter pin :P

Uh, i use a cotter pin to?

[evan402]

ok i miss spoke, it has 38 and a 170 jet in it. That isnt stock. But it seems like it should be the right jetting, It DOES bog when i get on it WOT. but only at the high rpms. the filter was extremely dirty and i have cleaned it. starts up fine and idles fine. NO popping or backfiring. i havent put it back together since cleaning the filter so that may be the problem but it seems like somthing a little more than that. I never thought of the choke being damaged or not working properly. This is my first 4 poker and the carbs are a bit more complicated than the 2strokes.

the whole axle doesnt have play, just the hub. i must admit i didnt give it to much of a good look but its definately on the hub the rest of the axle has no movement. I thought it just needed tightening but it was getting dark friday night and the next day blizzard hit us so i havent messed with it besides the carb. i will def get a pic of the washer spacer thing.

Thanks for the response guys.
trailrider your quad is effing sick and what jets are you using

[trailrider894]

I don't remember the last jets i had in it. lol Gotta go look. I would tighten your hub and replace your cotter pin. Then probably go out and see how it performs past 3/4 throttle. I think your main is off a bit.

Thanks about the quad. Its been a real joy ride getting it ready for the race season next year. I have been sick on and off with health problems and knee problems and now i am recovering from mono, so my rebuild has been setback, but it will return, hopefully, a the best 400 on the forum or should i say 426. ;)