440 ex overheating

[wxhitmanxw]

Hello Im new here and i just bought a 400 ex with a 440 bore kite, white brothers pipe, high performance cdi box, stage 2 cam and stock carb. I took it out last night and the pipes were cherry red. I took the spark plug out and it was white whice tells me that im running way lean. I also found that I blew a head gasket. I have a 170 jet in the carb now i put a smaller needle in to help richen it up a little bit. My question is will this help cool my motor and should i upgrade to an edelbrock qwik silver carb?

[BlasterEaten250]

airscoops and a larger oil tank will help. and the jetting will help too. what compression is it? if the compression is to high and you are running to low octane gas, that could cause it to overheat.

[wxhitmanxw]

Im not sure of the compression ratio Where can i get an over sized tank and cooler

[zeppelin]

richen up the jetting, and put some air scoops on it if it doesnt have them already, then leave it alone, i wouldnt worry about the head pipe glowing too much, all bikes do it.

[EXevan91]

lol, not supposed to....

[GPracer2500]

You can force most any headpipe to glow (like holding the throttle open in nuetral) but excessive or even noticable glowing is generally a sign of lean jetting.

[wxhitmanxw]

gpracer so do you think by richening it up it will help it run alot cooler

[GPracer2500]

If the carb jetting is lean for your engine it will run hot. Richening the jetting will allow the engine to run cooler but don't get too carried away with upping your jet sizes in the quest for a cool running engine. You don't want too lean or too rich--you want just right.

Aslo, if you have a high compression piston (like say 12.5:1) than you'll need to run a race fuel. Pump gas with high compression = detonation = excessive heat and destroyed engines.

[honda460ex]

True true... And on buying another carb, don't buy an Edelbrock. I owned one for a week and got rid of it. If you talk to Chris Earlywines, 250b class champion from a few years ago, and a guy who also owns his own indoor track now, he will tell you the same thing. He had a racer try and sell him one, he told them no, and before it was over with, the guy just gave it to Chris. They are not what they are all cracked up to be. My suggestion, look for a 450r carb, '04 or '05 model. They are great because they can still be easily started in the cold, and they wake a decently built 400ex up as far as power and how it runs. Only problems is the choke lever has to be removed, and the air boots have to have a little shaved to fit the bigger carb. Stock is 35.5mm, the '04 '05 450r's are 42mm, big difference. But on the choke, you can custom make something, but honestly, you don't really need to. A couple pumps on the throttle and it will fire every time without the choke in cold weather. Mine does great and has never had a problem. But yeah, your head pipe glowing that bad definately means your bike is running lean. On a good jetted YFZ the pipe will still glow if you get on it hard enough, but it's not common on a 400ex.

[Big - D Racing]

OK defnitely run leaded race gas if you don't know the compression just to be safe anything over 11:1 should run race gas truthfully or atleast a 50/50 mixture. Defnitely richen up the carb, despite what other people are saying your pipe should not glow, k maybe if sitting in neutral and revving it to the moon. Unless you have a titanium pipe they tend to glow red because they are extremely thin, so show signs of heat earlier. As for edelbrok carbs, the person above me has no clue what he is talking about nor does the racer in the b class he is talking about. They are excellent carbs, they just get tune different than a standard carb, and actually they are easier to tune once you are use to them. Instead of changing a jet like a traditional carb you change a needle. the design of them allows you to not have to make adjusments due to altitudes. I have had my 400ex since it was brand new stock, I have ran everything. Includes the fcr 39 carb, the std. edelbrock, the stock carb, the doug eichner edelbrock 440 carb, and even an 05 honda 450r carb. My fav. for my 440 in terms of performance is the eichner carb, then the fcr 39, then the std edelbrock, then the 450r, and last stock. The eichner carb will produce slightly more power than the fcr but the tuning of it is abvsolutely amaizng and revolutionary for an atv. Once use to it, you will never want to change. Now if you are a type of guy who all you know is standard carbs with std. jets, and you want to stay with what you know and can't take the time to learn something new than the edelbrock is not for you, and on that same note either is fuel injection which is what every quad will soon be. Try new things and learn them before you bash them. For the money you can't go wrong with an fcr 39 or the eichner carb on the 440.

[wxhitmanxw]

Would the blown head gasket have contributed to the overheating?

[GPracer2500]

Originally posted by wxhitmanxw
Would the blown head gasket have contributed to the overheating?

Other way around.

[nakomis0]

You put a smaller needle in to richen it up aye?.... Well thats a good start but most guys put a larger jet in to richen it up. Try changing the jets not the needles. Your just gonna creat more jetting troubles.

You are running lean, and too hot because of it. Which, like GP said was most likely the cause for the blown head gasket.

If it was me I would make sure the airfilter is clean, oiled and correctly installed. I would also check for other intake leaks. I would repack the exhaust if needed. Then I would install a 178 main jet and go from there. You might even wanna put that old needle back in.

[knight rider]

a head pipe is suppose to glow 4 to 6 inches at night mine does to and i have a 440 with hot rods crank stage 2 cam 11:1 compession piston rev box all that stuff

[Big - D Racing]

Originally posted by knight rider
a head pipe is suppose to glow 4 to 6 inches at night mine does to and i have a 440 with hot rods crank stage 2 cam 11:1 compession piston rev box all that stuff

That's funny cause I have had my 440 for 3 years as a 440 and 2 years as a stock 400ex motor, and my pipe has never glowed on any of the pipes I have ever had which include stock, fmf powerbomb, curtis sparks x-6, and now the duncan fatboy 4. And 50% of my riding is night riding at glamis. If I ever notice my headpipes glowing I would shut my bike off right away and figure out what is causing the heat before I cause other problems to my motor. Headpipes are not suppose to glow, excpet really thin wall headers like white brothers titaniums. If your is glowing it is because it is running too hot. More than likely because of your jetting. The only bike I have seen a header glow on stock was the 04-05 450r because they're jettng from the factory was off, and this was a big complain by all the magazines. A jetting correction solved the glowing head pipe. Now the head pipe is suppose to get hot but not that hot to where the metal is glowing red. OF course again the titanium pipes are the exceptioon to this because of their thin wall construction.

[nakomis0]

I had my 440 for about 5 yrs.

My pipe glowed red........and I was running lean. Other than that never red.

[wxhitmanxw]

I bought a dynojet kit for it i tore the carb down and it already had a 170 jet in it and the biggest jet that came in the kit was a 170 but the needle that came with the kit was slightly smaller so i stuck that in as well and i also discovered that the needle was set the whole way down.

[GPracer2500]

Aftermarket jets (like those made by Dynojet) may not be the same as a Keihin jet.

170 Dynojet likely does not equal 170 Keihin jet.

[honda460ex]

Your main jet being a 170 is probably about right. You can buy bigger jets one at a time or in sets of 5. Say a set of 170,172,175,178,180... Something like that. But your main problem would be your needle. Your needle set all the way down is running very lean. Set it to the middle notch and see how the motor acts and check the color of the plug. That should solve your glowing problem. But on newer quads such as the yfz or 450r, the headers will glow occasionaly even if jetted properly. That is of course only when you are getting on the throttle. 400ex's are just not a quad known for a glowing header. So if it is, you know it's running lean.

[wxhitmanxw]

so do you think i should put the spark arrestor back in the pipe?