Glowing header?

[ti2ibal1]

Tonight I went out for a ride and on the way back to the house, I wound it out in 5th for a good piece down the road.

When I got to the end of the road and slowed to head down the trail, I happened to glance down and noticed the header pipes were glowing red.

I've only put about 3 hours on this thing since I bought it and they have all been in cold weather. I know I should re-jet it, but is this the cause of the glowing header or is it due to the fact that I had it wide open for a stretch?

[07trx400ex]

It is jetted lean from the factory for emissions purposes, which causes it to run hotter than it would if it was jetted more on the rich side.

[ti2ibal1]

Originally posted by 07trx400ex
It is jetted lean from the factory for emissions purposes, which causes it to run hotter than it would if it was jetted more on the rich side.

So the combo of me riding it with stock jetting and it being cold outside is causing to run the pipes red?

I understand the principles, I just didn't know if it was a common trait for this specific model.

Thanks! :)

[07trx400ex]

Mine is stock and it has not been red yet, but I don't have anywhere where I can hold it wide open for a long time, so I don't know if this is normal or not.

[dang400ex]

So it has no aftermarket parts on it? I wouldnt think it would be running that lean...mine never did but I guess some ppls do...but if it has a pipe or anything else than it might make sense

[07trx400ex]

Another thing to think about, the affect of the night. Since it was dark, you probably would not have noticed during the day.

[ti2ibal1]

It's bone stock.

True about the night part, it was pitch black when I noticed it.

I don't know, I don't feel comfortable running this thing with the pipes glowing. I can't imagine it's good for it.

Perhaps I'll just chill out on riding until the weather warms up.

Also, how often should one go about checking and adjusting valve clearance? I bought the bike used with 14 hours on it, and he had the valves checked and adjusted at 12 hours along with an oil change. How long should I wait before I go abouts doing that?

As for the header glowing, I really wouldn't worry about it. Its dark, its cold and they have flames fired up there *** on every cycle, I think as its night you might notice glowing more so than the day.

I change my oil every 6-8 hours, I like it to come out a similar colour to it going in.

[ti2ibal1]

Originally posted by Ikilla2
As for the header glowing, I really wouldn't worry about it. Its dark, its cold and they have flames fired up there *** on every cycle, I think as its night you might notice glowing more so than the day.

I change my oil every 6-8 hours, I like it to come out a similar colour to it going in.

Thanks. I was asking more about the valves than the oil, though. Do you just check and adjust when you hear them tapping too loud? How loud is to loud?

[tanner 222]

as for the vavles on my 400 i had i just went til i could just hear them in there tapping and got them adjusted. with my LTR i get them done about every 5-6 months and i race mx so they get their wear.

for the glowing header, dont even worry about it, its normal for bikes to do that especially with the big 400 or 450 motors, maybe not so much like the 250's. i know my 400 did all the time when i was running it for a while and with my LTR with a dasa system if i leave it idling for 3 or 4 minutes the head will glow red so dont even worry about it, its normal

[ti2ibal1]

Originally posted by tanner 222
as for the vavles on my 400 i had i just went til i could just hear them in there tapping and got them adjusted. with my LTR i get them done about every 5-6 months and i race mx so they get their wear.

for the glowing header, dont even worry about it, its normal for bikes to do that especially with the big 400 or 450 motors, maybe not so much like the 250's. i know my 400 did all the time when i was running it for a while and with my LTR with a dasa system if i leave it idling for 3 or 4 minutes the head will glow red so dont even worry about it, its normal

Thanks for the heads up. :)

[416exfreak]

You could still go ahead and re-jet the carb.

My 440 done it a couple of times after I rebuilt it, and the pipe was new. Once I got some carbon built up in the header, it quit doing it.

I dont see how warmer air will be any better for a hot pipe than colder air.:ermm:

[frenimy]

Most 4 strokes do that. I have seen everything from stock bikes to highly modified bikes have their headers glow. It is just a normal thing.

[ti2ibal1]

Originally posted by 416exfreak
I dont see how warmer air will be any better for a hot pipe than colder air.:ermm:

That's my point. If it's glowing red hot now in the cold, is this thing gonna catch fire in the summer? :D

[dirtmerchant42]

yea man its a normal thing mine does it at night as well

Originally posted by 416exfreak
You could still go ahead and re-jet the carb.


I dont see how warmer air will be any better for a hot pipe than colder air.:ermm:


Nobody said warm air was any better for a pipe.

Its basics physics bro, more cold air in, more performance out and the more performance.... the more heat and the more heat the more the chemical composition of things change and that is denoted by a glowing header witch you might not get on a warm and humid day………..maybe!!!

[Pipeless416]

cold air causes a leaner mix, which equals a hotter engine.. mine did this a couple winters ago when my jetting was a little off and i had some 87 octane gas.. bad mix. and for you guys asking about the warmer weather, yes it will heat up the engine a little bit more, BUT the mix will be a little bit richer.

[hotbo400ex]

if it was mine i would be looking at my plug,glowing red wow:eek: imo thats not a normal idea on anything.re-jet the carb will help they are way lean from the factory.if the header is glowing red,then there is alot of heat being transfered to the ehxuast valves.not good and the piston.:( i have never heard this being normal on anything before.maybe im wrong.travis

[ti2ibal1]

Originally posted by hotbo400ex
if the header is glowing red,then there is alot of heat being transfered to the ehxuast valves.not good and the piston.:( i have never heard this being normal on anything before.maybe im wrong.travis

That's kinda what I was thinking. When I ride again this weekend, I'm gonna keep my eye on it. I mean, I was just going balls out down the road for a good 1/4 mile before it was glowing, that could have had a lot to do with it.

[hotbo400ex]

1/4 mile is not very long to hold it wot.the cool air should have cooled the mill down some and had a positive affect on the motor,imo.check your plug for sure,if a motor is to lean and you run for extended periods of time it will do more harm then one thinks,i hope this helps and maybe its really nothing,travis

[ti2ibal1]

Originally posted by hotbo400ex
1/4 mile is not very long to hold it wot.the cool air should have cooled the mill down some and had a positive affect on the motor,imo.check your plug for sure,if a motor is to lean and you run for extended periods of time it will do more harm then one thinks,i hope this helps and maybe its really nothing,travis

I'll check the plug before I go out this weekend. Maybe I'll get it out tonight or tomorrow after work and putt around while checking the header. I have never noticed it before, and I always ride at night.

I've never had any issues with stalling. Every now and then I'll get a few "pops" out of the muffler, but other than it being hard to start, I never have any performance issues.

If I was to change the jetting, what size pilot and main would I get? I've read to go with a #42 pilot. Where is a good place to order these?

*EDIT* Nevermind about the where to buy part. I called a local dealership and they have a #42 pilot there. I'm gonna pick it up before work and throw it in tonight.

[hotbo400ex]

#42 pilot that outta do just fine.:cool:im not sure on the main hwat size they have from the factory yet to go into mine,but i would only go up 1 size on the main:confused:

[hondaking52]

wen my buddy got his motor back from being rebuilt his header was also glowing, adjusted the valves and no more glow, and i run mine wide open for a mile or so for awile and my header has never glowed, even in cold weather.(o and u couldnt hear my buds valves tapping)

[TRXRacer1]

You don't need a 42 pilot. The 38 is fine even if you pipe it but if you feel the need to change the jet that only controls your idle to 1/8th throttle I wouldn't bother with anything more then a 40. For the main you could need to bump it up a couple sizes if it's still below freezing in Toledo. Start with 2 sizes and go down if needed. The red glowing header doesn't sound like a major issue. 95% of the riders out there don't get to ride WOT down an open area in the dark of night to see what happens. If you did that same run during the day you'd have never noticed.

the glowing header is because of it running lean. At night here in Florida in the winter when it was colder, we used to rid ethe powerlines to get to this sand dune for drag racing. After riding there the header had a slight glow and everyone after 1 run the headers were like a flash light lol. We were all jetted for normal 70-100 degree weather and riding in 30 or 40 really leaned us all out.

[ti2ibal1]

Well, I installed the #42 pilot and it fired right up being cold. I didn't have to monkey with the throttle, choke or anything. Just pumped the gas 3-4 times and hit start. (It is kept in a 55 degree heated garage.)

After letting it idle for a while, I took it for a spin, while keeping an eagles eye on the header. Sure enough, anytime I wind it up quick or stay on the throttle under acceleration, it would glow. Not super bright, but you could clearly see it glowing. (Again, I'm riding at night whilst keep an eye on it.)

I'm just gonna go easy on it during the rest of the cold weather months. I don't wanna burn anything up and have it down when the weather gets nice.

[CSR400EX]

i would try a one size bigger main for the colder weather (50 and below) and go back stock in the warmer weather (50 and up). my YZ426 hybrid's header glows only about 2 or 3 inches out of the motor, but ive seen bone stock YFZ450 headers light up like christmas at night lol

[ti2ibal1]

Originally posted by CSR400EX
i would try a one size bigger main for the colder weather (50 and below) and go back stock in the warmer weather (50 and up). my YZ426 hybrid's header glows only about 2 or 3 inches out of the motor, but ive seen bone stock YFZ450 headers light up like christmas at night lol

After paying close attention to it tonight, I noticed that it only gets to glowing when under heavy throttle. (Rapid acceleration for an extended period of time, or prolonged full throttle.)

When I'm just farting around, it's fine. (A majority of time my time on my 400ex is spent farting around.) :chinese:

I'll keep the jetting in mind. It didn't take me very long at all to rip it all apart and get the carb off. If Winter is deciding to stick it out around for any longer, I'll re-jet the main.

[tanner 222]

but if its only getting after heavy throttle, your jetting should be good. if it was hot or even lean it would glow red whenever it is running. if i were you check your plug to see if your running lean or hot, dont go by the colour of your pipe.

[mat1977]

I noticed you mentioned your quad had only 3 hours on it.Every new bike I've had the headers glow really bright during the 'break-in" time.Something to do with the new metal getting hot.I actually called a dealership years ago after I bought my 1st dirtbike wondering the same thing.Since then all my after market headers have done the same thing when new.

no matter what the stock main is lean so i would put a 150 in.

[boylan300ex]

Mine did this after i rebiult it and got an eftermarket exhaust but one there was some carbon in the header and it burt all the oil from lubricating the parts before installation was burnt out it was fine

[TRXRacer1]

Originally posted by FoxHondaRider
the glowing header is because of it running lean. I will agree that a glowing stock header is something worth looking into but glowing does not always equal lean. The reason is that the stock header is a heavy duty build. In a lot of thinner aftermarket head pipes it is not that uncommon to see glowing and does not automatically mean something is wrong. You can have some glowing in a perfectly tuned machine.

yeah on stainless steal aftermarket headers they will turn orange/blue/purple even when jetted right. But fr the most part the stock headers glowing means its lean. At least that was the cause for 6 400ex's at the same time to have their headers glow after 1 drag race, even stock jetting isnt suficient enough for weather like 30 degrees, in 80 or 90 its not bad but I see it a lot whenever it gets colder everyones jetting is screwed up from the change and you will see glowing. Its always better to be richer losing a HP maybe not even than be running lean. Thats the beauty of living in Florida, 4/5 of the year its between 70 and 100*F and that other 1/5 is like 50 - 70*F. If you do night rides in winter after a cold front thats when you will be below 50*F and see that glow come out.

[ti2ibal1]

Ok, here is some food for thought...

The other night I jetted my my bike with the #42 pilot. After install, it started right up and ran like a champ. I took it for a spin and the header glowed just like normal. The only thing I noticed is that it fired right up with no issue being cold.

Fast forward to tonight. I get off work and head over to a friends house that just bought a brand new (left over) '07 400EX. We go out in his garage, it's cold as hell, and its fires right up with stock jetting. He takes it for a spin and then I do, the whole time watching the header. No glowing at all with stock jetting.

I leave his house and come home to start my bike and go for a spin. (It's snowing like crazy.) I pump the throttle a few times and hit start. Nothing. It just cranks and cranks.

I pull the plug. It's light tan like it's running great. I re-install it and try again. Nothing.

I smell gas. I try and try again. Nothing.

I pull the plug back out and it's pitch black and soaking wet. I take a torch to it and then a wire brush. I put the boot on it and hold it against the block while cranking it and get good spark. I re-install it and try again. Nothing.

It will idle and act OK for a few seconds, then it will die. I let it idle until the block got hot, and it still wouldn't accept any throttle without dying. The motor is warm. It should be running fine!

I'm at wits end. I'm about an inch from taking it to a local performance shop and telling them to fix the issue for me. (It pains me to do that.)

[ti2ibal1]

Well, I changed the pilot back to normal and it still won't do anything.

Won't run, stinks like gas, thanks Honda.

Off to the shop goes my NEW piece of ****. :mad:

[TRXRacer1]

Originally posted by ti2ibal1
Ok, here is some food for thought...

The other night I jetted my my bike with the #42 pilot. After install, it started right up and ran like a champ. I took it for a spin and the header glowed just like normal. The only thing I noticed is that it fired right up with no issue being cold. The pilot is going to have zero effect on the header glowing. None what so ever. It only controls idle to 1/8th throttle. Basically you'll only notice differences in starting and idle.



Originally posted by ti2ibal1
I pull the plug. It's light tan like it's running great. I re-install it and try again. Nothing.

I smell gas. I try and try again. Nothing.

I pull the plug back out and it's pitch black and soaking wet. I wouldn't put too much thought into this, sounds like a simple flooding.


Originally posted by ti2ibal1
Well, I changed the pilot back to normal and it still won't do anything.

Won't run, stinks like gas, thanks Honda.

Off to the shop goes my NEW piece of ****. :mad: Don't worry about that pilot, it will run on either one you have. Have you changed the plug yet? You can get spark by grounding out and bumping the starter on even a dieing plug. It might be chopping up when you rev up. If you've ever owned a 2-stroke for a while you know what I'm talking about. So get a new plug in there. Also have you checked your main to make sure it's clear? Your problem could be a few things but I'm betting its the plug or a clogged main. What size main are you running by the way? That's the one you want to bump up to richen the top end and help that glowing issue.

Are you giving it throttle while trying to start it? If you are stop doing that. If it's cold just choke it, pump it a couple times and turn it over with no throttle. It should fire.

[ti2ibal1]

I understand the pilot will have no effect on the header issue. I simply wanted to change it due to it hopefully making start easier when cold.

I just put a new plug in it yesterday. I set the gap and put it in there and it ran great. It's only when the motor is "cold" that it acts up. If, by the grace of the little baby Jesus, it will start and run, it's OK. If it's cold, it's like it just floods its self out. Do I have to put a new plug in it everytime I want to ride?

Their is absolutely NO REASON I should be having this much trouble getting this thing started and running. It's kept in a 55degree garage! Of all the bikes, trikes and snowmobiles I've ever owned, this thing takes the cake for being the biggest let down.

I've got on eBay and am bidding a new carb. I have to believe something is screwed up with the one on my bike. Their is no reason for that thing to be running the way it is.

P.S. Sorry if my last post was a tad whiny. I had a few beers in me and was "venting". :macho