400EX Glowing Exhaust Question
#11
11-29-2004, 05:52 PM
T Rex Rider
What irritates me is!
Those 6-packs work pretty good.
What irritates me is!
Those 6-packs work pretty good.
400EX Glowing Exhaust Question
Mine does NOT glow when riding at night. I usually let it sit there and idle for at least 10 minutes or so to warm up.
My understanding is the most common cause would be a head pipe leak allowing air back into the cylinder and causing a lean condition. Never had the problem, but I have read if you spray some carb cleaner/starter fluid/wd40 where the pipe attaches to the cylinder at idle and it's got a leak, the rpms will rise when it sucks the fluid in. Might be worth a try (just to rule it out if nothing else).
Good luck!
My understanding is the most common cause would be a head pipe leak allowing air back into the cylinder and causing a lean condition. Never had the problem, but I have read if you spray some carb cleaner/starter fluid/wd40 where the pipe attaches to the cylinder at idle and it's got a leak, the rpms will rise when it sucks the fluid in. Might be worth a try (just to rule it out if nothing else).
Good luck!
#12
11-29-2004, 05:54 PM
#13
11-29-2004, 06:52 PM
#14
11-29-2004, 09:37 PM
400EX Glowing Exhaust Question
had this happen on my 300. my head pipe cracked and cool air got in and makes the exh burn very hot. this can melt down an exh valve fast. if it is cracked you should here a clicking or hissing sound every time the exh valve opens on the stoke. i could feel the exh leaking with my hand but only try that if the engine is completely cool before you start it will warm up fast, dont burn your hand. the trick of carb cleaner will work for intake leaks but i have never tried it with exh leaks
good luck
seth tynes
good luck
seth tynes
#15
11-29-2004, 10:27 PM
Extreme Pro Rider
GOT BOOST!
GOT BOOST!
Join Date: Jan 2004
Posts: 3,204
Likes: 0
Received 0 Likes
on
0 Posts
400EX Glowing Exhaust Question
That depends on the color. Bright cherry red or salmon and your literally playing with fire!!! A piston will start to get soft at a little over 1,500F (EGT). 1,600 and over, and you done.
Faint Red 930
Blood Red 1075
Dark Cherry 1175
Medium Cherry 1275
Cherry 1375
Bright Cherry 1450
Salmon 1550
Dark Orange 1630
You make the call at what color the pipe was. I set my EGT at 1,350 to 1,400F. I have run as high as 1,500 for a few seconds at a time but I don't recomend it; especially with a light racing piston. I don't like to see any color on my pipe, no matter how thin it is; that's just me though. Lean is mean, but I see no sence in pushing it.
Faint Red 930
Blood Red 1075
Dark Cherry 1175
Medium Cherry 1275
Cherry 1375
Bright Cherry 1450
Salmon 1550
Dark Orange 1630
You make the call at what color the pipe was. I set my EGT at 1,350 to 1,400F. I have run as high as 1,500 for a few seconds at a time but I don't recomend it; especially with a light racing piston. I don't like to see any color on my pipe, no matter how thin it is; that's just me though. Lean is mean, but I see no sence in pushing it.
#16
11-30-2004, 12:25 AM
400EX Glowing Exhaust Question
i don't call that BS by any means. the stock 450r's that i have seen do this too. here's whats going on. your giving it a bit of gas, the pipe glows. you just a bit lean on the needle. i think your getting confused on lean and rich conditions. rich is where the bike would run cooler and lean it would run hot in most conditions. rich is too much fuel where lean is a lack of fuel. well, you said the pipe quits glowing when you let off the gas. at idle, the pilot jet/fuel screw are primarily being used. so, since the headers are not glowing at idle, your fuel screw position much not be lean (which is a good thing). when giving it gas, the needle assembly is primarily being used (below 3/4 throttle that is). is it getting cold where you live?? if so, i would just lower the needle clip position and your problem should completly go away or greatly diminish. the stock headers on the 400ex are stainless. the glowing with stainless headers is more likely to happen. if you ceramic coat them, you may not notice it as much for example. i would say if your in cooler temps, just lower the needle clip position and you will be fine. the jetting changes pretty drastically from summer to winter. in the winter the cold, dense air has more available oxygen. this means you need to richen the carb up. if your getting more air, you need to give it more fuel.
#17
11-30-2004, 12:45 AM
400EX Glowing Exhaust Question
I had this problem also. My problem was the gas was old in the bike, and had a hole in exhaust on the right side where the gaurd is. THis was on a stock, then I put a after market on, BIG GUN and it was not jetted right. SO check your jetting and a hole in the exhuast. I never seen the exhuast do this except for these two times.
#19
11-30-2004, 05:52 PM
#20
11-30-2004, 08:00 PM
400EX Glowing Exhaust Question
Originally posted by: prudog
Recently, I washed my 2003 400EX and decided to start the machine to dry off the engine. While holding the throttle about 1/3 of the way open for about two minutes, I noticed that my pipe coming out of the head was begining to glow more and more red. After letting the engine return to idle, the red glow immediately began to go away. Keep in mind, it was almost dark outside when I was warming up the engine. I became concerned that my carb may be running extremely lean, and went to talk to the local Honda dealer in hopes of preventing any further engine damage since the ATV has less than 40 hrs since it was bought. The dealer told me that this glowing was normal when the pipe is viewed in the dark or dim conditions since the pipe is only one layer thick, as opposed to two layer pipes in the past. He went on to say that if you took any stock 400EX down the road at night it would look like a light show because of the glowing pipe. Can anyone with a stock pipe tell me if your pipe glows in the dark or can someone start their 400ex in the dark to see if your pipe also glows? I have never seen the pipe glow in the day, only when its dark, or in a dimmly lit area. Thanks for your input.
Recently, I washed my 2003 400EX and decided to start the machine to dry off the engine. While holding the throttle about 1/3 of the way open for about two minutes, I noticed that my pipe coming out of the head was begining to glow more and more red. After letting the engine return to idle, the red glow immediately began to go away. Keep in mind, it was almost dark outside when I was warming up the engine. I became concerned that my carb may be running extremely lean, and went to talk to the local Honda dealer in hopes of preventing any further engine damage since the ATV has less than 40 hrs since it was bought. The dealer told me that this glowing was normal when the pipe is viewed in the dark or dim conditions since the pipe is only one layer thick, as opposed to two layer pipes in the past. He went on to say that if you took any stock 400EX down the road at night it would look like a light show because of the glowing pipe. Can anyone with a stock pipe tell me if your pipe glows in the dark or can someone start their 400ex in the dark to see if your pipe also glows? I have never seen the pipe glow in the day, only when its dark, or in a dimmly lit area. Thanks for your input.