Engine Trouble

[CowboyJ]

Ok so I got a new tranny put it in and assembled my motor, I followed the DIY in the popular 400ex thread link. I got my engine running today and it idles crazy high, and I dont think it has anything to do with my carb as it was in a sealed bag during my rebuild. And also with my tranny, my neutral light will come on but I am most definatly not in neutral as my sproket spins while the motor runs. Im stumped, anyone ever had this problem before? PLEASE HELPPP!!!

[CJM]

Check to see if you throttle cable is twisted and check the adjustment at the throttle itself and inside the carb. if you take the cover off the carb you can see how far the screw is pushing up the butterfly.

As for the neutral light, you got a wiring issue of some kind. Double check all the connections and grounds.

[CowboyJ]

Well it doesn't have anything to do with my throttle cable itself, I can put it on full choke and it idles down a good bit but I dont have any throttle response. And thanks ill check to see if I can find that bad connection, I hope thats what it is and not somethin inside!

[dxcody]

Air leak! (maybe?)

Air leaks can make it idle high.

Im guessing you replaced the crush gaskets?

Fastened them down good?

Carb is on tight?

Slip on is fitting tight?

[CowboyJ]

Pretty sure the carb is on good and tight! And crush gaskets? Been working on engines almost all my life and never heard of them, so therefore I haven replaced them...lol what exactly are they?

[CowboyJ]

Nevermind, you mean the copper gaskets between my exhaust header and my head right? No I did not replace them...but I highly dought this would cause my engine to idle as high as it is.

[CowboyJ]

Do you think maybe my cam gear is a tooth or 2 out of time? Would that cause my engine to idle that high? I messed with the air/fuel screw a good bit and nothin happened, it idled the same.

[quad2xtreme]

it is normal for the sprocket to spin in neutral if you don't have a chain on the sprocket. Can't tell if you mean the light just comes on when it is in gear or if you mean the sprocket is spinning because you started the engine before having the quad completely put back together.

[CowboyJ]

Well I got my idle taken care of so now thats outta the picture now I gotta focus on my tranny. I put the chain on and I can put it in neutral and the light comes on, but it will NOT roll freely like it should, I strated it and took off in 1st gear and tried to shift to 2nd and as soon as I shifted up my quad locked up and shut off. I tried it once more and it did the same thing. When the quad is not running I cant shift into or out of gears. Idk whats up. I also need to adjust my clutch a bit.

[CowboyJ]

Im just really stumped, I took my clutch cover off and the star that is bolted to the shift drum shows that I am most defiantly in neutral and my neutral light is on, but the bike still will NOT roll freely. Any suggestions anyone? Im open to try anything at this point.

[JOHNDOE83]

Does the quad roll freely without the chain on?

[CowboyJ]

Yessir it does!

[CowboyJ]

Its most definatly something in the transmission, I'm gonna tear it back down tommorrow. Im thinking I forgot something really stupid like a thrust washer or something along those lines. And also the transmissions are constant mesh correct?

[suspension101]

The middle shift fork on the 400EX are easy to put in upside down. They will go in easily this way. Make sure the "C" on the center shift fork is facing the same direction as the "L" and "R" on the other two shift forks.

So what was wrong with your idle?

[CowboyJ]

Ok I will check that out thank you!!! And as for the idle me and my buddy fooled with the air/fuel screw all evening and no matter what position it was in it made no difference in the idle, I went out the next day to fool with it and started right up and idled fine, I tweeked the air/fuel screw to my jetting specs and it was perfect. Almost like it just fixed itself...

[CowboyJ]

Well jus my luck the shift forks are in their right places facing the correct direction. Im still stumped to what is going on with my tranny.

[suspension101]

I've had a tranny before that someone else worked on and they put a 2005 450r shift fork in a 2006 bike. I had to really try to figure out exactly how they worked out of necessity at that time. They really aren't that complicated when you watch what every gear is doing when in each position.

I would first start off by printing the microfiche for the transmission. Then on that picture write the number of teeth on each gear it should have. Verify by the picture that everything is facing the correct direction. Wish I was there to help you out. You can put the cases together and hand turn it before you assemble the motor completely. I do this on EVERY motor I do.

[CowboyJ]

Thanks man I appreciate it and I may do that! Never really thought about doing that, but it seems like a very smart thing to do!!!