starting prob... have no clue

[johnnydufus]

at a race about a month ago i was running full out in 4th gear then it bogged down like a blaster. my 400ex will not start, it tries to turn over and it doesnt fire up

at first it didnt have spark so i checked all of the electrical and replaced a fuse and cleaned all the connections and i now have spark... i put in a brand new plug and it still doesnt start up. so i searched and read about cleaning carbs so i just got done cleaning my carb and still nothing. i checked to make sure it had compression and sure enough it has compresion but it still wont fire up... help me please

i dont know what else to check

any help would be very appreciative

[44oEX]

check the stupid stuff..... kill switch, is the gas on?....

[FoxMxRiders]

does your starter turn?

check for a spark,if you have a grounded wire

check if you have gaz on your spark plug

[kuba1506]

have you tried to start the bike by just pushing it to see if it will start. and if it does you can possibly narrow it down to a starter problem. i dont know maybe try it and see

[johnnydufus]

come on guys i'm not a dumbazz

i am going to try to pull/push it tommoro

the starter does turn, it has compression and spark. the plug i pulled seemed to be fine as in rich or lean but it was just old and shot

[duke416ex]

Did it make any strznge noise before it died? Maybe it jumped time, have you had it apart recently, or do you maybe have an aftermarket rev box, if so try the stock one.

[ZQ8Dude]

well with no spark and the starter turning, im willing to bet its your timing chain.

[johnnydufus]

i have a whitebrothers rev box (they suck and it came on the quad) and i have no factory box. its down to a engine and frame right now. i did pull the head to make sure the gasket was still good and it is.

wierd noise??? i dont recall of one, if you've ridden a blaster and bogged down thats what it was like.

how hard is it to replace a timing chain? how do i know if the timing is off? what do i look for?

once again thanks guys for all your help

[ZQ8Dude]

you might wanna pickup a manual because im a beginner at these engines. if the there is an accessable timing chain cover from the outside, thats where you start. pop off the cover and look at the 2 gears that the chain surrounds. there should be a "Dot" on each gear. they should line up perfectly at some point during the rotation of those gears. If the chain jumped, then they wont line up

[duke416ex]

Well, did you replace the head gasket when you took the head off, if not I would replace that, and if you took the head off you definatley need to know how to set the timing.

Take the 2 round covers off the side casing on the left side if you are sitting on the bike. Turn the crank counter clockwise til you see a line with a t by it in the little hole and line it up with the mark. You need to take the valve cover off and look at the cam, the lobes should be down and there are two marks on the cam gear that should be pretty close to even with the top of the cylinder, if they are not the timing is off.

[44oEX]

Originally posted by ZQ8Dude
you might wanna pickup a manual because im a beginner at these engines. if the there is an accessable timing chain cover from the outside, thats where you start. pop off the cover and look at the 2 gears that the chain surrounds. there should be a "Dot" on each gear. they should line up perfectly at some point during the rotation of those gears. If the chain jumped, then they wont line up

it's not like a car, that would be to easy

[JOEX]

Originally posted by johnnydufus
come on guys i'm not a dumbazz....

With a NIC like johnnydufus how are we to know:confused: :devil: :devil: :devil: :blah: :D

Anyway.. you might want to look at trying a different CDI

[johnnydufus]

so when it is TDC the cam's marking should be flushly horizontal with the edge of the head

the bike has been sitting in my garage for a month and i am out of school with nothing to do, i'll get bored and go over all the easy things a few times

i'm gonna get a new cdi box asap

[JOEX]

Originally posted by johnnydufus
so when it is TDC the cam's marking should be flushly horizontal with the edge of the head

the bike has been sitting in my garage for a month and i am out of school with nothing to do, i'll get bored and go over all the easy things a few times

i'm gonna get a new cdi box asap
There's three marks, two should be horizontal and the third should be pointing up.

[pr0t0type670]

JOEX do you think you could paste an enlarged version of your avatar? I would like to print it out and bring it to the truck accesorie's store and have them pring me out a decal for my back window.

[44oEX]

Originally posted by johnnydufus
so when it is TDC the cam's marking should be flushly horizontal with the edge of the head


they might not be perfectly flat with the head, if your timming chain is stretched a little it will be a little off, but not much, if it's off alot then you are a tooth off, or you timming chain is way stretch.

if you chain is stretch the rear mark will be a little to low and the front a little to high

good luck

[johnnydufus]

i checked it and i found that the front marking is off by one tooth and when i opened up the headcap oil was all over the place. what could have happened?

when the timing chain jumps what can happen to the other parts of the motor?

[44oEX]

well it`s normal for the oil to come out the valve cover, if you don`t want to make a mess you have tu lif the front end up to drain out the oil.

When you jump the timming the valves could have hit the piston, witch will destroy the piston, bent the valves, maybe the valve guides, rockers, cam. I would take off the head and check if the piston is messed up, if it`s not then your valves should be ok, it depends with way the timming skiped. but you might want to check the timming chain and tensionner, cause the timming is not supposed to skip.

[ironbear77]

mine ex did this and the auto tensioner was the reason the spring inside broke allowing the adjuster to un adjust the tension on the chain allowing it to jump time and bog out . I since fixed it and still cant get the 400 to start . and I have tried to time it both ways still no luck.....
GO FIGURE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!:confused:

[jamienlogan]

my tensioner broke and made a valve smoke the piston and messed up alot of stuff

[benbuilt4u]

i have a 400ex with the same problem i have everything compression spark and fuel still just cranks and wont start.

[ironbear77]

pull started it today with my 300 ex. ran like crap still might be 180 out on time so I am going to tear it down again and rotate timing 180 then I'll try it again............................................. .......:(

[lafinrat]

You can't get the timing 180 off on the cam--the cam turns at half speed of the crank, so one revolution of the crank would put the top mark down, one more rev would put it back up again. Does that make sense? If you lined up the timing mark at the crank, and lined up the two marks on the cam gear horizontal, its okay.

BTW. Generally speaking, one tooth off either way the bike will still run. Two teeth and you'll bend valves the second the motor turns. If you have certain work done to the motor (milling, more duration, etc), your clearances will be tighter. A race built 400 motor will smack valves at one tooth off.

You need to RECHECK the basics, and try another CDI if you haven't already.

[lafinrat]

One quick work of advice:

Pull the plug and put a screwdriver in the hole as you turn the motor by HAND ONLY. Verify the mark you are using to install the timing chain is top dead center. I have seen factory flywheels with multiple marks.

[44oEX]

yeah the facotry flywheel does have 4 marks on it...but you just use the one that has a T on it...T for timming

[PismoGuy400]

i had the same problem. timing was the deal. follow everyones guide you should turn out ok. good luck

[ironbear77]

Hey johnny Guess what mine is fixed and that stupid lil spring and plunger for the valve was the thing it has to be timed also so get your in time and spin the piece on the cam around by hand it will only spin one way and watch to the rear of the head for the plunger to go down and stop turning it when it releases or pops up and your set. I hit the starter button and it fired right up like a match. and runs great I can wheelie in 4 gears now.YEA BABY...


and for who said it cant be 180 out you rrrr wrong ask you honda dealer or take your apart a change it and you will see first hand good luck man holler if you need some help and thanks to inputting their past experiences on here it helped me get mine going............................................. ..............................................:coo l:

[johnnydufus]

thanks for still helping and trying to solve my problem. i got a job at my dealer and am getting all the parts at cost. i sold my 400ex to my bro and bought a z400. but its all good cuz i'll still ride the 400ex from time to time, (you know when i want to woop some 450r *** in xc races)

[bones_chevyboy]

i would definatly check the timing then check the cdi

[400EXtreme]

lol this was was from like 5 months ago :) last year

[johnnydufus]

still helps other ppl when they are searching to fix their bikes