Our service manual hasn't come in time so we've been putting my brother in laws 400EX back together after getting it bored. We have the cylinder and the head on. Finally got the cam chain back on. Ready to install the cam adjuster back in the hole and it hits the guide and it still needs to go in another 1/4 to 3/8 inch. It is tight. We didn't adjust it when we took it out, just took off the 2 bolts and pulled it out. It can't be off this much can it just putting it back together? Any help cause I don't understand how to adjust it?

Also, can anyone give me the break in procedure regarding the same machine.

Fixing to go back and give it a look. By the time we were finishing it up last night we were getting so tired the most trivial task was getting difficult so we quit before me messed something up.

 

The cam chain tensioner is an automatic one and will extend itself fully when you remove it. You must retract the plunger before you install it. Take the bolt out of the back, and you will see a place for a small flatblade. Stick a small screwdriver in and turn the screw clockwise and you will see the plunger retract. Hold it in until you get it bolted in place.

 

DZZY is right but it is a S O B. If you have a hard time then it is going in correctly.

 

i was thinking you had to turn it counterclockwise for it to retract??? heck i don't remember, maybe it is clockwise.

 

Okay, I'm fixing to go give it another shot. There is a slotted nut (going by memory) that is threaded on the inside for the screw. You're saying to turn the nut clockwise until the plunger retracts and then reinstall it? Nothing else? Does it automatically retension itself once installed. I wish the manual had arrived and we wouldn't be having this problem but, I will rely on you guys.

Thanks.

 

It is clockwise, got it installed, not much of a problem. Went to fire it up and it wouldn't start, had unhooked a couple wires and forgot to hook them back up. Thought that was the problem. Still won't start, pulled spark plug cap off and installed a plug and she fired. Tried again, still nothing. Pulled spark plug out of engine, wet with gas, blew it off with air hose and reinstalled. Still nothing, like it's flooded, which it probably is. Giving it a break and letting the battery charger work it's magic on the battery. Gonna try it again here shortly.

It should fire right up shouldn't it?

 

you need to make sure you have that timing right before starting it. if it is wrong, it will either run like crap or not at all. with the T mark aligned up on the flywheel, make sure two marks on the cam sprocket align evenly on the head. the 3rd mark should point up. if the 3rd mark is not pointing up, rotate the flywheel one more revolution until the T mark is aligned up again. now, the 3rd mark should be pointing up. make 100% sure the two marks align with the head and the other line is facing up. all it takes is one tooth off on the cam sprocket to make the bike run like crap. with this being said, you can not put the tensioner back on. you will want to retract the tensioner all the way with a really small skrewdriver. hold it retracted while you install it. this isn't the easiest to do, but can very well be done. tighten the bolts holding the tensioner to the cylinder. now quickly pull the skrewdriver out of the tensioner and you should hear a snap. this is the tensioner hitting the timing chain. it is a self adjusting tensioner and should be set right now.

before starting:

make sure you put oil in the bike
make sure your fuel is in good shape
turn the fuel on
make sure the run switch is on
adjust your valves properly
make carb adjustments if you just put some mods on the bike

good luck

 

IT WAS THE VALVES!!!! Valves were too tight, readjusted them, VIOLA, started right up. I knew we put the thing back together right. Fixing to break it in. Thanks all.

 

whatd u get it bored to?

 

It was bored 0.020" over. It was worn 0.007" so it would have been marginal to just go 0.010".