400ex motor issues.

[kpennepacker]

I have a 01 400ex. Just put Wiesco piston in it. New Timing chain and adjuster. Has a Hot cam stage 1 cam. I bought it pieces. Had the head off the quad with two bent intake valves. I replaced them with OEM valves. Lapped them in and put in new seals. Air snorkel was missing so I plugged it and pulled the air lid off and went up 3 jet sizes. Has stock exhaust. I know its rich but figured I'd dial it in once I had it running. It had no key either so I have a two way switch black wire on one side and the red wire on the other side. Key had 4 wires to it. This is how I got it to start. Also I am waiting on clutch cover gasket so I used 1211 Gasket maker to put the gasket on. So thats the down and dirty of everything I did.

I started the quad for the first time fired right up and ran for 10min. Onced it seem to get warm it shut off. I hit the start button fired right back up ran for about a min then shut off. Hit the start button again ran for a min and again shut off. So I left it sit. I was frustated.

Went back next day. Choked it and motor fired right up not even trying. Ran for the 10 min and again once motor seemed to get warm shut off. Fired right back up then ran for a min and shut off. Fired up again and shut off after a min. Exactly like the first time.

Each time it shuts off right before it dies it sounds like the motor gets dry or like a squeaking noise. from the left side.

This has been a rough project and I just want to ride. and I am becoming very stumped. Sorry for being so long I wanted to give as much detail as possible so I could get so help/



What could this be....
Is the oil pump..Causing no oil circulation and once it get hot it seizes.
Is it the starter.
I don't think it fuel issues because it idles and revs during the first 10 min with no issues.
I've triple checked timing, and its perfect.
I've triple checked valves.
Has new spark plug.
Has New battery.

Any help would be a blessing.

[kpennepacker]

Just realized. At the parts store the guy gave me a NGK D8ea. The bike never had a plug in it. I see this is the wrong plug. Would it cause all of this.

[AtvKid4Eva]

is the carb stock? or has it been messed with? sounds fuel related to me.

[powerbomb400]

It shouldn't. After it dies are you still getting fuel. Mine did that and it was pulling a vacuum in the tank and shutting off the fuel supply. A coil getting hot would do that. After it cools off its starts producing a spark again. Maybe others will chime in and give a opinion also.

[kpennepacker]

Carb is stock other that a little bigger main.

The vacum make sense since it runs for the 10 min and then act stupid. I am going to retry it tomorrow and pop the the plug out of the bowl when it does it to see if there is fuel there.

I started it the first time and had a clear fuel line before I got the stock "S" style line and you could see fuel in the line the whole time, but I never check it at the bowl. Thanks for the replies.

I was also think coil also. Just was wanted more oppions before throwing parts at it.

Any other ideas.

[drew416ex]

im wondering if you accidentally clogged an oil port putting on that gasket maker. That could do it.

[crownandmonster]

Its not oil related...it would have already locked up if you have ran in that long with no oil. I would also lean towards a coil.

[kpennepacker]

After long and drawn out trouble shooting I pulled the clutch cover off and my oil pump is shot. I bought a new one. Motor still turns over free so I hope its not fried.

What do you guy think. Motor still turns over freely....

[caseywoods5]

my 400ex will also shut off when it gets warm and refuses to stay running until it cools back down... but when mine shuts off i know it's a fuel issue because it starts pouring gas out the overflow. once it cools down it starts back and runs good again. as soon as cash comes my way i'm ordering tons of jets (from 150-190) and a 42 pilot and a carb rebuild kit (even though it is literally a brand new carb). hopefully some better jetting and a carb rebuild will have me running golden. just an idea for you to check into.

EDIT: i just read that your oil pump is bad, sorry for being a little late haha