Need Help! Just bought a 400ex

[Zillafreak]

Hello, I just purchased a 00 400ex.. I love it! I think it's bored over cause its fast. A couple questions for ya, what is a good oil to run in my quad? When should I change my oil?. Please let me know. Thank you

[Otis.Leo]

buy the Honda oil... eveyone changes theirs on different lengths of time. most common around this website seems to be every 10 hours of ride time.. guys like me... once a summer.

[ben300]

buy the Honda oil... eveyone changes theirs on different lengths of time. most common around this website seems to be every 10 hours of ride time.. guys like me... once a summer.

honda oil is garbage...its just junk, genergic 10w-40 oil and is really not that good.


i use, and a VAAAAST majority of ppl run rotella 15w-40. its a way better quality oil, is a bit heavier and the EX's like a heavier oil, and its like $14.99 for a 5 quart jug....you can get two oil changes out of it, and you'll spend less than half of what you would on the honda GN4.


as for oil change frequency...it varies. the average trail rider, id do every 10 hours. i myself change my oil every race, and change the oil filter every other race.


http://www.atvriders.com/vbb/showthread.php?493032-what-motor-oil

[Hondaman97]

In my opinion I run Lucas 20-50 so called (motorcycle oil) and change the oil and filter about every 10hrs.

[HondaRacing83]

I change mine when its low and dirty usually about every 2 months and i ride every week haha

[cheater13]

The Honda GN4 oil definitely isn't junk. I been using it over 3 years and it has been treating me good. I drag race a good bit too. I change mine every 2-3 months, depending on how much I ride.

[Zakradu398]

Hello, I just purchased a 00 400ex.. I love it! I think it's bored over cause its fast. A couple questions for ya, what is a good oil to run in my quad? When should I change my oil?. Please let me know. Thank you

Hmm, you don't happen to be from BHQ are you............

[on the rocks]

a VAAAAST majority of ppl run rotella 15w-40. ]

im one of them.

[DragonGunner]

I've had a 99' EX since 99' and a 2001 since 2004....I run Spectra 10w 40 always. Oil filter change every other oil change. 15 hrs of hard racing, 30 to 40 hrs of trail riding. The 99' still going strong as a 406, still has original clutch with heavy duty springs and a zillion hrs on it. I won't even think of using any other oil.

[matholland]

I run valvoline in everything I own, and it has never let me down.

specifically the stuff in the black jug 10-40 @ autozone for atv's/bikes

[HondaRacing83]

I run Gn4 hasnt let me down yet

[KKiowaTJ]

I put 10 hours a week or more and 8 of them are WOT wood's. Bought the quad and joined here and have run GN4 10w-40 year around since them. It runs warm but not much more than a buddys 416 and Pennzoil/Rotella 15w-40. To each their own, I choose to run what it was built to run on. Many brands to choose from.

[Fix29]

I too run 10w-40 GN4 and have never had an issue with it. I've also always ran GN4 in my older street bikes and never had an issue. There are plenty of good oils out there but the main thing is keeping up on your maintenence. If you do that the bike will usually treat you pretty good in return.

[CJM]

the oil so long as it meets spec isnt important, what is important is changing it often. I change every 15hrs or so

[2001400exrida]

Changing the oil is key to maintaining engine life. There are most definitely better oils though and in most cases you get what you pay for except in the case of Rotella. I've run in my 400's for 5 years and I have no complaints. MY 450 gets amsoil, but that's only because it's a race machine and I prefer a synthetic oil in that motor. Everybody has their preferred oil, the main thing is to stay away from oils that are not wet clutch approved (JASO) and oils that have moly in them.

[HondaRacing83]

Actually half the time i run yamalube honestly because my dad buys it for his grizzly and if theres 2 quarts of that on the shelf ill just use it its the same damn thing. When my quads low on oil and i dont feel like changing it and im goin riding ill just add some. Yes sometimes i mix yamalube and gn4 haha

[ben300]

Actually half the time i run yamalube honestly because my dad buys it for his grizzly and if theres 2 quarts of that on the shelf ill just use it its the same damn thing. When my quads low on oil and i dont feel like changing it and im goin riding ill just add some. Yes sometimes i mix yamalube and gn4 haha

yours must really be burning oil up. mine never goes that long between oil changes that i see a loss in oil volume.

[HondaRacing83]

Yeah valve seals goin bad. Its not that bad i just dont think you guys understand how much i ride lol. Smokes on startup and smokes on decel kinda bad when its hot. The motor in mine has never been into, i just adjusted the valves for the first time about 11months ago.

[Zillafreak]

Wow thanks guys! I'm now running rotella and it's been great. So far so good but now I'm having carb problems. My 400ex sputters when I hit the gas and it idles when it wants to. It'll go fine at half throttle & full throttle. It has a 42 pilot jet. I'm putting on a new aluminum air box with no lid tomorrow and ill mess with the carb also if that's the problem. I'm currently running a airbox with a lid with holes in it(on the bike now). Let me know what you guys think. Oh also my 400ex engine gets hot right when i start it up no clue why. Its over 70 degrees everyday where i live but i started it in a fairly cool garage.. Its bored to a 416 or 426 i believe. Help me Get this ready for the weeknd so i can ride. Thanks appreciate it.

[sand_blaster]

My bro's honda 450 would do the same thing instantly heat up. Upped the poilet jet no change, gave it a valve job & fixed it right up. Sooo that could be the same issue with yours, cause your poilet jet is about the right size.

[Zillafreak]

My bro's honda 450 would do the same thing instantly heat up. Upped the poilet jet no change, gave it a valve job & fixed it right up. Sooo that could be the same issue with yours, cause your poilet jet is about the right size.

Everything's in spec. The valves can cause it to sputter ?

[DragonGunner]

Your pilot is just for start up, idle...it could be blocked and needs cleaned....I like putting some carb cleaner in the tank every so often to help keep the carb clean also. Higher octane will help keep the ngine a little cooler....hear any knocks or pings, sign of too low a octane.

[cheater13]

Your pilot is just for start up, idle...it could be blocked and needs cleaned....I like putting some carb cleaner in the tank every so often to help keep the carb clean also. Higher octane will help keep the ngine a little cooler....hear any knocks or pings, sign of too low a octane.
Unless you have a hotcam. It'll ping a lot then, but that's normal.

[Zillafreak]

Your pilot is just for start up, idle...it could be blocked and needs cleaned....I like putting some carb cleaner in the tank every so often to help keep the carb clean also. Higher octane will help keep the ngine a little cooler....hear any knocks or pings, sign of too low a octane.

I'm running c12 I believe it's 103 octane. Do you know why it sputters under half throttle ? Ill clean the pilot jet and see if that's the problem. Lmk

[Zillafreak]

Anybody know ....?

[#484]

A dirty pilot jet will cause your sputtering at half throttle or below

[Zillafreak]

A dirty pilot jet will cause your sputtering at half throttle or below

It's a brand new jet. Ill clean it. What else causes sputtering under half throttle. The bike was idling real good when I took the carb boot off..

[KKiowaTJ]

It's a brand new jet. Ill clean it. What else causes sputtering under half throttle. The bike was idling real good when I took the carb boot off..


Does it have a good seal with no leaks since you took it off last? Binding hooking the throttle cable back up?
If it was running fine and all you did was take it off, Find the loose end you didn't catch. Also a stuck float will chock your power if the carb was off and tipped upside down many times. Could just need the clip bent/adjusted and bowl cleaned.
But id start with the carb boot and move back, Fire it up and spray brake cleaner at it idle all over to look for any leaks. Good luck either way

[Zillafreak]

Does it have a good seal with no leaks since you took it off last? Binding hooking the throttle cable back up?
If it was running fine and all you did was take it off, Find the loose end you didn't catch. Also a stuck float will chock your power if the carb was off and tipped upside down many times. Could just need the clip bent/adjusted and bowl cleaned.
But id start with the carb boot and move back, Fire it up and spray brake cleaner at it idle all over to look for any leaks. Good luck either way

Ok I cleaned the pilot. Now the bike idles high. I checked the cable and all that and everythings good..There has to be a leak somewhere, If not then idk what the problem is. Can a leak make the bike idle high on startup??

[KKiowaTJ]

Ok I cleaned the pilot. Now the bike idles high. I checked the cable and all that and everythings good..There has to be a leak somewhere, If not then idk what the problem is. Can a leak make the bike idle high on startup??


Now you have to remember what you messed with when it was running bad to try to cure it. IMO set the a/f screw at 2 turns out and dont turn the idle adjustment until its 100% warm, Then set you idle. Just my opinion, Someone more knowledgeable about these carbs will chime in im sure.

Gas drys gaskets and seals. When I take them off, I hit the rubber with a multi purpose lube or grease just like the air filter. An air leak will cause the high idle, So that's where to look/start. I know its a PITA, But just take it back off, And take your time going anal/OCD putting it back together.
Or you can spray carb or starting fluid around the bike running and when it stumbles, That's usually the leak.

[Zillafreak]

Now you have to remember what you messed with when it was running bad to try to cure it. IMO set the a/f screw at 2 turns out and dont turn the idle adjustment until its 100% warm, Then set you idle. Just my opinion, Someone more knowledgeable about these carbs will chime in im sure.

Gas drys gaskets and seals. When I take them off, I hit the rubber with a multi purpose lube or grease just like the air filter. An air leak will cause the high idle, So that's where to look/start. I know its a PITA, But just take it back off, And take your time going anal/OCD putting it back together.
Or you can spray carb or starting fluid around the bike running and when it stumbles, That's usually the leak.

found the leak! There's a opening where the intake boot meets the airbox it's the bottom of the intake boot been cut to fit this airbox. How do I seal up the hole? Can I use some sealant or something ? Let me know thanks for the help man

[KKiowaTJ]

I would try and find a new boot for the carb/box. If you use any RVT it could chip off and end up in your motor. If its possible, Try and sleeve it with a large radiator hose and clamps.
If not possible, Try and put some tape on the inside of the boot where air will pass over and maybe a better seal. Or wrap it with electrical tape until its totally covered and wont let any air or debris in.
Any pic's of the set up or boot/leak are itself by chance?
But id still buy the correct part and be done or if its a custom part, Find out what they used and fix it that way. You don't want any foreign objects in your motor.

[Blodg]

Wait a minute, if the air leak is where the air boot meets the air box it is not going to cause issues with idling. Of course it will let dirty air into the engine and does need to be fixed. An air leak that causes a high idle is in the carb or between the carb and the intake manifold/boot thus causing a lean condition.

[2001400exrida]

it will go lean which can cause idling issues.