Another 400ex vibration post...

[Destructo]

I have been reading through some posts I searched on. I just bought an 01 400ex on tuesday this past week and thought it vibrated more than it should, but I have never owned one.

It is a physical vibration in the motor, idle is smooth, just in the mid range and up it seems to have some excessive vibration but seems to run strong.

All I have ever ridden in 4-strokes and we own a 99 Foutrax 300 and it feels nice and smooth to me, as does my 85 XR200R.

I noticed the air filter is dirty, so i'm going to clean that, and it seems to run great and will idle perfectly in the "on" position on the tank, so I don't think its a fuel problem, but I really don't know. You can feel the vibration on the whole bike, handles bars, foot pegs, seat.

Maybe if somebody could post how to check the counter balancer I would do that after cleaning the air filter. If somebody can just tell me how to check it I can handle the rest, I have the tools and abilities to do anything.

[cals400ex]

go over the whole bike and tighten down every bolt. remember the footpegs and skid plate, motor mounts, etc. i would go and grab each wheel and shake it back in forth. it you feel play, you need new bearings. if you feel play in the steering column, you might need the new bearing that goes down near the bottom of the column too.

[Destructo]

I don't have to be riding it to feel the vibration, it doesn't have anything to do with the bike moving at all, it does it when you rev in neutral not moving anywhere.

[Myrtle150]

have you tightened all the motor mounts up?

[mojoe2878]

mine starts vibrating sometimes too, its usually just loose or a missing motor mount bolt.
to check the counter balancer you will have to do a complete disassemble of the engine split the case's and all , remove the balancer and go to a machine shop that has the machine to check to see if its balanced. thats a big job too, and i would not do that unless its a last resort.

[Destructo]

This motor is a 01 and doesn't look to have ever been taken apart, the motor itself is all stock right down to the air cleaner and exhaust, I really doubt its internal to the motor, its probably just normal and i'm worrying too much, I never ridden anything bigger than a 300, so it may very well be normal, it doesn't affect performance at all, so I should probably just quit worrying about it.

I did remove all the body work today and check all the engine mount bolts and all were tight, check the exhaust bolts too and most of the front end bolts. Its still causing some noise but I probably just missed some bolts I need to check.

[speedy400]

Wait! Check out your pilot jet in the carb. When I did my 416 kit I had a way too big pilot, it vibrated like a mofo and somewhat seemed right but it was louder then normal and just didnt seem right at all.-darren

[Destructo]

Originally posted by speedy400
Wait! Check out your pilot jet in the carb. When I did my 416 kit I had a way too big pilot, it vibrated like a mofo and somewhat seemed right but it was louder then normal and just didnt seem right at all.-darren

Hmm, ya know, I pulled my spark plug today and it was black, but my filter was pretty dirty and I figured that was why.

What should the stock jet and pilot be? I don't know why anyone would have changed it from stock since it has a stock air filter and exhaust, but who knows.

I guess pulling all the body work and removing the gas tank is the easiest way to get at the carb? and do I need to remove the carb to get at where I need to?

[speedy400]

you need to-remove the side panels, gas tank, then plastic shield under tank, then you should be able to take off the carb, its really not that hard after your 1st time. Take the carb, flip it over(dont worry about the gas spilling out of the overflow) there is 4 phillips screws that hold on the bowl, under there, you'll see the main jet(brass one in the middle), by that one there is a hole that goes down like an inch or something, take a small flathead screwdriver and unscrew it(the pilot is at the bottom of the hole). I think the stock pilot is like 38, but I dont remember its been awhile since I had my stock carb.. someone confirm that number please-darren

Originally posted by speedy400

Wait! Check out your pilot jet in the carb. When I did my 416 kit I had a way too big pilot, it vibrated like a mofo and somewhat seemed right but it was louder then normal and just didnt seem right at all.-darren

Never thought about it being from the carb, hmmmm

Just figured it was from having a true 13:1 compression and poorly designed rod.

[ReconRider25]

mines been doing that since the first day i bought it. either its gone away, or i dont really notice it anymore. now i got a rattling hmf that annoys me.:mad:

[speedy400]

Originally posted by ReconRider25
mines been doing that since the first day i bought it. either its gone away, or i dont really notice it anymore. now i got a rattling hmf that annoys me.:mad:

is the quiet core rattling? if so, take some exhaust sealant and put it on bolth sides of the large outside washer on the quiet core, the sealent is rubbery and if you put more on 1 side than the other, the other end of the core should just stay put against 1 side... adleast thats what i did and it's fixed.

[Destructo]

Well, this really isn't my concern, but, I do have something that the engine vibration is causing to make noise just under the handle bar area, I think its just the plastic around the gas tank where its secured with the little plastic rivots. I can track down noises.

I put a new spark plug in it today and gapped it to about 32 thousands (I wasn't sure exactly what its supposed to be) and rode it around some tonight, gonna check the plug after awhile and see what color it is, if its black i'm gonna lean the carb out some.

[Destructo]

I put in a new spark plug last night, practiced doing some wheelies ( :cool: ) and then rode it around some this afternoon and did a couple hard runs and immediatly shut the engine off so I could examine the plug, its white and not black/sooty, its actually a little TOO white if you ask me, but I should probably ride it a little more to make sure i'm not getting in-correct readings, but I rode it for half an hour or more, so I may be running lean for some reason, thats how white the porcelin is, I am pretty adept at examining the plugs in my 85 chevy and it indicates a lean condition to me, but the old one I pulled out was black, so who knows, I guess it just depends on how I ride it? I bounced it off the rev limiter once so I was running it pretty hard.