Is my 400ex busted??

[busted400ex]

I have a 03 honda 400ex

Today I adjusted the valves it was not as easy as befor, the motor would turn easy and then coast a little when I put the 17mm wrench to turn the motor.

I got them adjusted put it all back together and started it. it did not start that easy. and had a noise in the motor like a clunking sound, would not go above idle and then the pipes turned red hot .

what the hell?
it ran strong befor I parked it. I rechecked the valves 4 times and still no difference.
is the compression release stuck? I have no idea were to start. any info would be useful.

[plkmonster2]

Are you sure that you are adjusting them at TDC? It sounds like compression is leaking past the valves.

[busted400ex]

thanks for the input.

I think so. I took the valve cover off. so no rocker were touching valves. I did this to see if the adjustment was off or I had rocker damage. I turned the motor over with no rocker on it with a wrench and it would not compress it just coasted twice in the stroke.

I put a lot of thought into what could cause this and I think a ex valve is stuck open. that could cause the coasting in the crank/piston assy. by that I mean you start to turn the motor over manualy and it keeps going till it stops with a clunk.but will turn freely then coast again.

I only saw the left pipe glow red after 40 sec of running at an idle.

if it needs a valve job who in arizona could do that for me. and do you think the piston is ok if the valve seat is trashed? but I guess I will find that out when I pull the head.

I have never pulled a 400ex motor apart befor how is the best way to do this so I can inspect the piston and sleave? and of course valves.
and I run VP 110 fuel. becuse of some mods that the last owner may have done. pump gas would make it over heat and knock. and this is the fastest anything I have been ever faster than Gsxr 750 and the banshee. not top speed of course. but I was thinking of putting it back to stock if I was to rebuild just so I can ride it longer than a few months and not haveing to keep rebuilding it.
thanks for your input.

[busted400ex]

oh yeah I was adjusting them with the -t mark.

[400exrider707]

You probably adjusted them wrong. There are TWO TDC!! You need to be on the compression stroke TDC. When you took the rocker cover off were the cam lobes pointing downwards? The lobes should be down and obviously the cover needs to be on in order to adjust them. Once its at TDC on the compression stroke it will normall have play in all of the rockers. You should be able to slightly wiggle them through the valve cap holes. They probably wont be loose now if it is adjusted wrong, so best bet is to take the head back off turn it over until the cam lobes are pointing down then reinstall head and adjust your valves again.

[busted400ex]

for what your saying kinda makes sence. but I think some damage has happed. nothing can glow red hot and be ok. something must have warped.

like I said even with no rocker arms the motor will not compress as it should becuse nothing getting out of the motor with the valves shut.

how do I know what TDC to adjust the valves at? maybe I should take it to the dealer befor I trash it more.

I am worried that the head has issues now.

thanks for the info.

[duke416ex]

Unscrew the individual valve covers. Turn the motor over til the intake valves open and close then look for the t mark. That should be tdc.

maby there is carbon buildup on the exaust valve seat. I would grind the valves.

[bwamos]

Originally posted by mittimj
maby there is carbon buildup on the exaust valve seat. I would grind the valves.

Nah not yet. Sounds like his timing is just out of whack. Get the timing right first then deal with the damage. Or he may just damage the fresh work.

He's probably ok as long as it wasn't run very long.

[6858-400ex]

is it possible u turned the motor backwards when getting the tdc

[frosti108]

what happens if you turn the engine backwards? (clockwise)

would anything bad happen? because when i was adjusting my valves the other day i accidently turned it clockwise before i turned it counter clockwise.... but it runs fine now so who knows...
:confused:

[JDiablo]

Originally posted by busted400ex
for what your saying kinda makes sence. but I think some damage has happed. nothing can glow red hot and be ok. something must have warped.


thanks for the info.

alot of the headpipes turn cherry red at idle,so i wouldnt worry about it that much

[busted400ex]

did you guys remember me saying that I turned the motor over with the rocker cover off. so there was no rockers on the motor. I turned it over by hand and the motor would not compress. no body commented on that. and that is the issue that concerns me the most.

most times a motor with no valves opening letting the compression out would be a ***** to turn. this motor turns easy and coast a little by itself. right after TDC.

[duke416ex]

Even with the cover on and motor together, a 400 motor isn't to hard to turn over on compression stroke. If you are worried about the compression, do a compression check. When you turned the motor over with the starter, did it turn over really easy or did it sound like it did before you rebuilt it. If compression is real low, then the starter would be wizzing when you hit the button.

[busted400ex]

well when I last started it with the electric starter it turned over at the normal speed but had a clunk. I think the valve lash is mute at this point. becuse it has nothing to do with how easy it is to turn over. I think the left ex valve is stuck open. and the clunk could be the piston hitting the valve. and that would explain why the left pipe glowed at an idle. and the motor was makeing a clunking sound when it ran.

what I could have done is adjusted the valve lash wrong and may have bent a valve. but I will not know till I tear it down.

how is the best way to take the head off? I hope it is just a bent valve or cooked seat. I am sure its the gas I was useing. VP 110 has lead in it.

[busted400ex]

well I readjusted the valves with the cam faceing down. but it still clunks and is hard to start but it sounds like it has compression.

well I am thinking I am done with this machine. its for sale has lots and lots of high doller stuff on it. too much money invested and not wanting to spend more.

[duke416ex]

What's it got on it, and what are you wanting for the stuff. Really, I wouldn't give up that easy. You should be able to tell if a valve is open whenever you have the valve cover off. Just look to see if they are all out about the same amount. Besides that, when you get that far, all you have to do is take the cam out, be sure not to drop the chain down in the motor, undo the header and carb and take the 4 head bolts out to take the head off and look at the valves from underneath.

[busted400ex]

I have been thinking. I will just sell this..

The 400ex has whitebros revBox. FMF powerbomb header with titanium ama pipe the blue one. houser extended A arms. great plastic yellow. comes with a full set of ITP sand stars front and rear Never used! good factory tires on bike, with a spare tire and rim. raceing Scott bars and grips. off road running lights. Six pack rack with gas can holder built in. its a 2003. has A MSR fast clutch lever.

I am asking 2700 for it. the bike will need top end work. maybe a valve job. I set the valves wrong and may have burnt a valve.

[Syrus]

Sweet deal, but i think such a little problem like that can be solved with just some help dude. Get a friend to look at it, or take ur time with it. Dont give up, those motors are pretty simple to work on. Check it all over, talk to some ppl around ur area, and talk to the motor pro's here. You'll figure it out.

[busted400ex]

I know it might be something simple but I just think I would screw it up again. I never knew it had two TDCs It ran fine till I rechecked the valves trying to make the top end quiet. I guess all 400ex's are loud.
a local shop said 500 to fix it and if its all toast 1000. I think its just a burnt valve. I just do not have the spare cash to fix it. and I need another bike, one that can be on the road.

will trade this for a Vespa in good shape.