Need some help on timing my 400ex

[$$motoxstar40$$]

I have a 1999 400ex i went out last month and bought a 440 kit for it and me and my buddy started to take the motor apart (the top end). After we got done taking the motor apart i got invited to go on a riding trip down in florida, but the problem was that i needed to send out my sleeve to be bored for the 440 kit and that was going to take about a month do to the fact that they were sending it to los angeles.I decided to hold of on that so i could ride in florida. Im down here now and im in the process on putting the bike back together and i got to the part with the cam, I need some tips on how to set the timing, i saw that on the cam sprocket there is 2 lines on each side of each other and i was reading that on a 300ex you just line them up with the sides of the top of the motor. Is this true? Is this it? i want to find out exactly what to do so i dont f$ck anything up or hafto take it all apart again, so if any one has any pointers please let me know ASAP, Thanks....Larry....

[mikeminyard]

As long as you didn't let the cam chain go loose, your timing is fine, you just put the cam in how it would be at top dead center (assuming you took the thing apart the way the manual says) and make sure the lines are in line with the top of the head. Hotcams used to have instructions on their website. Also, make sure to use lock-tite on the screws that hold the cam to the sprocket.

[$$motoxstar40$$]

Thanks for the info, What exactly do you mean by letting the cam chain go loose? the cam is in now and the chain is really tight so basically make sure the lines are lined up?

[mikeminyard]

What I meant was, that when you take the cam out originally, you are supposed to keep tension on the chain. This keeps the chain from falling off the sprocket that is in the bottom end. If the chain is loose, the crank could turn and the chain would be off a tooth or two. This would either advance or retard the timing.

[$$motoxstar40$$]

Thanks, i put eveything together last night and tried to fire her up. It was crankin but didnt fire.Seems like its not getting any fuel.

[mikeminyard]

Are you sure that you put the cam in with the lobes facing the right way? Usually they are down when you take the valve cover off, and that is how they should go back in. Other wise look for simple things. Is the fuel on? If the carb's float bowl was drained when you took the carb off, you may have to pump the throttle a while until it gets full. You can also take the carb off and pump the throttle. You should see fuel squirt out of the accelerator pump. If this is happening, then something is wrong in the engine. Also check to see if you are getting spark.

[GPracer2500]

Lobes up or down doesn't really matter. It's just that if you install the cam with the lobes facing up then after the cam is installed you'll need to rotate the crank 360 degrees to get the engine at TDC on the compression stroke before you can adjust the valves.

When the piston is at TDC and you install with the lobes facing up your engine is now at TDC on the exhaust stroke. Install with the lobes facing down and the engine is now at TDC on the compression stroke. No reason to install with the lobes facing up but if you do then just rotate the crank 360 degrees and it's just like you installed with the lobes facing down--no need to reinstall the cam or anything.

[RangerRick]

Heres what I wrote in the other thread but in this case you can use the timing marks because im assuming you dont have the sparks timing key.

Turn the piston to as high as it can get in the bore(TDC)by uscrewing the center plug in the case cover and turning that 17mm bolt till you get it right.put the head on and be careful not to get the timing chain snagged down in the base.After bolting down the head put on the cam.The timing chain sprocket should have 3 marks.The middle points up,the other 2 line up with the top of the head when you look at it from the side.Make sure the cam lobes are facing down.Now continue to install the valve cover etc.Hope this helped.

[$$motoxstar40$$]

The lobes are facing down. tonight i tried again and i replaced the plug because when it tries to start it sounded like it wasnt getting any spark but then again it doesnt seem like its getting gas either. the bike shoulda been flouded with the amount of throttle i was giving it, but yet it didnt smell like gas and when your bike gets flouded it stinks like gas. I dont know if a jet is clogged or what, all i know is i spent so much time and money into the bike im gettin so pissed off so any more pointers i would appreciate it. thanks....

[halfraptor]

if you dont know if you are getting spark you can remove your plug and hook it back up to your coil (the lil rubber piece or cap) and let it rest against your block so its grounded and turn your motor over and watch for spark this will let you know if you have fire!

[mgraff400ex]

just out of mere curiostiy when you had everything apart did you take the jug off. if you did did you break a ring on the piston or something along them liines. i guess what i'm getting at is does the engine have compression?

[$$motoxstar40$$]

Seems like it has compression everything sounds good the pistons not hitting the valves air comes outa the exhaust when it cranks like it always did its like its not getting fuel i dont know but thanks for all your help....

[JOEX]

Stock cam? If so did you put the decompression spring and plunger back in?

[$$motoxstar40$$]

good point where exactly does it go?

[aviator4]

It goes right here. This photos shows the removal of the spring and plunger

[$$motoxstar40$$]

I def need the plunger and spring is the plunger by any chance called a dowel pin? cuz thats what this is showing on this sitehttp://www.yamahaoftroy.com/fiche_section_detail.asp....thanks for the help guys....

[GPracer2500]

Originally posted by $$motoxstar40$$
I def need the plunger and spring is the plunger by any chance called a dowel pin? cuz thats what this is showing on this sitehttp://www.yamahaoftroy.com/fiche_section_detail.asp....thanks for the help guys....

Nope.

PLUNGER, CAM SETTING (prt# 14125-KV2-940)
SPRING, PLUNGER (prt# 14126-KV2-940)

[JOEX]

Originally posted by $$motoxstar40$$
I def need the plunger and spring is the plunger by any chance called a dowel pin? cuz thats what this is showing on this sitehttp://www.yamahaoftroy.com/fiche_section_detail.asp....thanks for the help guys....
No, the dowel pins are those sleeve like pieces that are in various locations on the motor. There are a couple on each side cover and on the head cover maybe more...

The parts in the pic I posted are called the plunger and spring, #4 and #5 respectively on the schematic. Servicehonda.com has a better view;)

[JOEX]

Originally posted by GPracer2500
Nope.

PLUNGER, CAM SETTING (prt# 14125-KV2-940)
SPRING, PLUNGER (prt# 14126-KV2-940)
I'm a little slow sometimes:p

[$$motoxstar40$$]

i really appreciate all the help you guys have givin me im not stupid im actually pretty good with motors exc. its just these little pain in the *** peices, now i looked and theres nothing called a plunger, if u could just give me the numbers so i can just order off the site and how many i need, would not having these little peices cause my bike not to start, thanks again guys problem almost solved....

[jhr400EX]

It will not start without the plunger and spring if you have the stock cam in it. Without those in there, the compression release is always on; holding one of the exhaust valves slightly open. It lets out enough compression that it won't start.

[$$motoxstar40$$]

thanks guys finally got it im going to order them from servicehonda.com, now all i need is 1 of each or what and anything else you can think of? thanks guys....

[jhr400EX]

Order 1 Spring and 1 Plunger and you will be set.

[turbotexas]

I know this is an old thread, but will the fact I am missing these spring and plunger pieces cause it to run like this...


http://www.youtube.com/watch?v=ra-aBikwHYI

[banisterjames]

if you were missing that plunger and spring your quad wouldn't even start. yours sounds like it needs the valves set with those feeler gauges.

[440exnacsracer]

just out of curiosity, did you install heavy duty head studs? if not, go ahead and order some. if not, plan on changing head gaskets on a regular basis

[turbotexas]

Originally posted by banisterjames
if you were missing that plunger and spring your quad wouldn't even start. yours sounds like it needs the valves set with those feeler gauges.
No I didn't and Yea I should have!!! It already had 2 heli-coills in it so I might have to use the smaller jug I have that came with it when I get around to getting that done... I got it running and am happy with the power now, but I need to get that fixed before it gets worse!!!