New Here... 400ex won't start... couple ??

[alexf4i]

Hey.. i'm new here and new to the quad scene. I've been riding sportbikes for a few years tho... Anyway, here goes my story, hopefully someone can help me out.

I bought a 2002 400ex a few weeks ago. Thing ran great when i tested it out at the guys house. Brought it home, it fired right up. Used it about a week later.. no problems. Then i decided to try out a twist throttle instead of the thumb throttle. Went out and bought a Motion Pro twist throttle and cable. Slapped that bad boy on and started up the 400ex. It ran, but the idle was really high and the headers were turning bright red. It was late that night, so i put her away until the next day. I go out the next day and adjust the throttle cable down by the carb cause it wasn't fully in. Now the throttle cable seems to be looser, cause it was tight the night before. I try to start the quad up, but now it just cranks but doesn't turn over.

I did a search on this board and found a few things to try, but had no luck. I played with the choke.. tried with it on/off/ and in the middle. Messed with the idle screw a little bit.. still nothing. Even played with the air/fuel screw. turned it 2 1/4-3 turns out... nothing. I checked all the connections made sure everything was tight, and checked to make sure there was no clog in the gas tank.. everything seems ok. The only thing i haven't tried is the spark plug. You guys think i might have fouled it by messing with the throttle cable so much? I'm gonna try that next, but i wanted to see if anyone had any other tips for me in case the plug doesn't work.

Sorry this damn post is so long, but i'm trying to be as clear as possible. Oh, this 400ex is bone stock. Thanks to everyone that reads this.. i know it's long... :D

-Al

[zephead400ex]

First off, welcome to the siteL)

Check the plug. If the headers were turning red, you are probably running lean also. When you hit the starter does it click like it could be an electrical problem?

However, I am not familiar with running/installing a twist throttle so I could be missing something.

Good luck.

[promisc]

Bright red header ? Not normal, looks like your setup is way too lean. Replace your plug and try to start it again. If it starts again, let the engine runs for few mins, shut it down and check your plug again. If its white, you have a problem with your pilot circuit. Maybe some dirt came into the carb when you changed the cable. Clean it. Use air pressure to clean circuits.

[alexf4i]

Originally posted by zephead400ex
When you hit the starter does it click like it could be an electrical problem?

Thanks for the quick replies guys and for the welcome... I appreciate it.

When i hit the starter, it sounds like it wants to turn over. It doesn't sound like an electrical problem. It sounds more like it's not getting any or enough gas.

You guys said i might be running too lean, excuse my stupidity, but how can i correct this? I'll also do a search to see what i can find out.

[cals400ex]

if the headers are really red at idle, your too lean on your slow jet or your fuel screw. the fuel screw is a fine tune adjustment for the slow jet. the stock slow jet is a 38. many people just go out and get a 40 or 42 slow jet to help things out. also, you will find a technique on how your bike likes to start easiest. i always went out to the bike pumped the throttle 3 or 4 times, turned the choke on full and just it the start button WITHOUT hitting the gas anymore. these carbs have an accelerator pump that will shoot gas into the engine. this can foul the plug really quick if you hit the throttle too many times. if the headers are really read at 1/8-3/4 throttle, your lean on the needle clip. you would lower the needle clip one position to richen the mixture up from 1/8 to 3/4 throttle. good luck

[alexf4i]

Thanks cals400ex... maybe i'll get a 42 slow jet and replace that when i replace my spark plug.

[pikey21]

ok first is the key on

2 is the lottle red switch on (the lines in the middle conecting)

[alexf4i]

Originally posted by pikey21
ok first is the key on

2 is the lottle red switch on (the lines in the middle conecting)

:devil: :D yeah.. they are. Thanks for checkin tho

[3x440ex]

Hey welcome to the site........Yep, you fouled a plug for sure it happens to me all the time.

I have a question for you.....since you bought the quad used, did it come with a plug wrench? if not you will need to buy one for the 400ex....no other wrench works on it that i know of.....good luck.

[promisc]

Originally posted by 3x440ex
Hey welcome to the site........Yep, you fouled a plug for sure it happens to me all the time.

all the time? not normal. Maybe your running too rich ?


I have a question for you.....since you bought the quad used, did it come with a plug wrench? if not you will need to buy one for the 400ex....no other wrench works on it that i know of.....good luck.

There is 18mm spark plug socket(whith rubber inside to hold the plug) on the market, you can find it everywhere. The plug is metric. DPR8Z for a stocker

[alexf4i]

thanks again guys

Is it normal to foul plugs often on 400ex's? If it is.. that kinda sucks.

I didn't get a tool kit with my 400ex, but like promisc said... i'm pretty sure an 18mm spark plug socket will do.. but it does needs to be 'Thin Walled' right? cause i have a regular sized 18mm and it won't fit... just my luck :rolleyes:

[Quadzilla]

If you took the carb off of the motor to install the cable (I've done it w/o removing the carb, but maybe you removed it), it's possible that you have a leak causing the lean condition. Make sure that the carb is inserted FULLY (push hard) into both boots (motor and airbox side) and make sure that the clamps are tight.

[promisc]

My '01 400ex dont foul plugs, i only change it for maintenance and to get a better spark after weeks of use. Plugs will blow if your not jetted right or not using the right plug number. DPR8Z or DPR9Z in very hot conditions.

My spark plug socket do not seems to be thin'er than other sockets. Maybe you have a stronger one.

[alexf4i]

Originally posted by Quadzilla
If you took the carb off of the motor to install the cable (I've done it w/o removing the carb, but maybe you removed it), it's possible that you have a leak causing the lean condition. Make sure that the carb is inserted FULLY (push hard) into both boots (motor and airbox side) and make sure that the clamps are tight.

I didn't remove the carb, but i was moving it alot... i'll check both boot connections.. thanks ;)


Originally posted by promisc
My '01 400ex dont foul plugs, i only change it for maintenance and to get a better spark after weeks of use. Plugs will blow if your not jetted right or not using the right plug number. DPR8Z or DPR9Z in very hot conditions.

My spark plug socket do not seems to be thin'er than other sockets. Maybe you have a stronger one.

That's good to know that it's not normal to foul plugs. I'm not sure what plug is in there cause i can't get the damn thing out with my 18mm socket. I'll just go to Sears later and pick up a thin wall socket.

Anither quick question... since i bought the quad used, it has alot of dry mud all over the engine. Would that effect this problem. Also, what's the best way to clean all that crap out?

Thanks

[promisc]

Use CASTROL SUPER CLEAN. Its a purple botle. Its works so great! Warm your motor(huh, when you'll be able too :) ), spray some CSC on it, let it works like 1-2mins, but dont let it dry! and rub with a rag or a brush.

[alexf4i]

Originally posted by promisc
Use CASTROL SUPER CLEAN. Its a purple botle. Its works so great! Warm your motor(huh, when you'll be able too :) ), spray some CSC on it, let it works like 1-2mins, but dont let it dry! and rub with a rag or a brush.

Awsome.. thanks ;)
I'll pick some of that CSC up and give it a shot when i get this thing running :D

[3x440ex]

Something els that will work even better is an aluminum brightner cleaner..you can pick some up at any NAPA dealer. it will make your engine look like brand new, however it is an acid and is very low in PH and if not nutralized it will soon start to corode your engine, little white spots will show up the next day. The best thing to use to nutralize it is the CSL. it is high in PH......but if you use the two together your engine will be bright and look like new.

[alexf4i]

Well.. i finally got her up and running. Replaced the spark plug and she fired right up... bought a few extras just in case too ;)
When i took the old spark plug out, it was really black and it smelled alot like gas, doesn't that usually mean i'm running too rich?

Anyway, thanks alot for everyone's info and help... u guys rock! :macho

[3x440ex]

Good to here that:) ....did the 18mm socket work?

[Ryan]

Originally posted by 3x440ex

I have a question for you.....since you bought the quad used, did it come with a plug wrench? if not you will need to buy one for the 400ex....no other wrench works on it that i know of.....good luck.

I had the same problem when I bought mine. what you need is a thin walled 18mm deep socket.

I didn't have one on hand, but had plently of 18mm deep sockets so I hit it with the grinder to make it thinner. It works fine now.

[alexf4i]

Originally posted by 3x440ex
Good to here that:) ....did the 18mm socket work?

Yep.. the thin walled 18mm socket worked.. it was as tight as a nun and i had to wiggle it alot for it to fit... but it did the trick ;)