Glowing header pipe

[maxtherat]

Yesterday I installed a new piston ect.. along with hotcams intake and exhaust cams. Bike started first kick but after about 1 min. of running at about 3k rpm the exhaust was glowing to the point that I felt that I had to shut it off. What causes this? I have noticed it on my 02 450 honda and this bike 01 wr426 DS, but once I start riding it goes away.Would it be best to just ride the bike to break in the cams or just hold it at 3k rpm idle? Thanks

[Brokenparts123]

haha, all bikes pipes will glow at night. Thats just how hot the exhaust temperatures are.

Its nothing abnormal.

[maxtherat]

it was mid afternoon but I was in the garage so it probably looked more distinct.

[Brokenparts123]

Hmm well, if it was fairly visibly bright out, then you probably shouldnt be able to see it glow. I know mines only visible when its dark out.

Maybe i'll let someone that knows what they are doing to field this ?

[pjriss]

Maybe the fuel mix is too lean?

[Solo]

They do that- isn't it neat?

[airbornedog]

My WR450F is completely stock and it will start to glow if the bike is not moving. "Only noticeable in a darker garage or at night." The radiator will also boil over into the resevoir if I sit with it while its hot out for a couple mins. These bikes wern't made to sit still obviously. As soon as you turn the engine off it quits glowing and starts cooling fast. Fast enough were I couldnt light my cigarette off of it. ?

[byggd]

From the FAQ sticky:

Q: Why is my header glowing cherry red?

A: A red hot header is usually a sign of a bike that is jetted too lean, a condition almost universally found in WRs with factory-set carbs. However, the WR does not like to sit on the stand and idle. It will get hot in a hurry if it's not moving. If you're just putting around and get a red header, it's normal. Just don't put your tongue on it until it cools. If it gets red during normal riding, go fatter on your jetting.

[purethumper]

it happened to me once in my garage i just urned the choke off and it stoped glowing but i just got hotcams stage 1 today and for the break in it sais not to let it idle and do some light trail rideing or something to break it in for 30 min just dont go to crazy

[jays22b]

they glow after 30 seconds of idle. after a minute they are getting very red. as said before the bike is not ment to be sitting still reving at 3000 rpm. what did u expect.................... steel starts to glow red around 700deg C or 1300 F

[stroker yz426]

yea i would have to agree letting the bike idle after the new parts install was not a good idea unless you were adjusting the idle or such....the cams' instructions do tell you to ride for break in, that way the whole engine is under "load" conditions......however if you have an after market pipe,usually they are thinner then stock and will glow faster...when i piped mine with cams she started to glow when i kicked her up to 3000 for a quick warm up to check the oil before a weekend ride...anyway if it doesnt stop i would have to agree that a jetting change is in order...and you might want to do the wr to yz timing mod if it hasnt been done yet....

[wizbangdoodle]

My '06 and '07 WR450's did the same thing. Very normal. Just get on it and ride.

[DB_Cooper]

GLOWING HEADPIPE IS NORMAL.?

AFTER DOING ALL THE MODS YOU MENTION,YOU NEED TO RUN A COUPLE OF GOOD "PLUG-CHECK" RUNS AND MAKE SURE YOU ARENT TOO LEAN.

FOR SURE IT SOUNDS LIKE YOU NEED TO RICHEN UP YOUR SETTINGS.

[cltrobd]

Please forgive my questions - novice here! What will the plug look like if the bike is running too lean? Consequently, what does a plug look like if the bike is running rich? I think mine is running lean based on some threads posted on TT. I'm looking for more inside information to the all important jetting questions and need a point of reference. If a plug observation will tell me where to start then that would be an easy way to start.

[maxtherat]

When you say yz timing mod, do you mean cutting the grey wire to change ignition curve to yz spec.? The cams are for yz and wr nothing different. I imagine they are along the lines of yz. I can't think of anyone that would want to change there cam timing to wr spec; maybe some for really tech. riding. If i was running too lean would it be the pilot jet or the needle? I'm pretty sure needle is stock, pilot is stock(42), main jet is 168. I plan on switching to 45 PJ but I don't know if I should switch to YZ spec or just raise the one I have by one clip. I would appreciate any help you guys can give me.

[pjriss]

When you say yz timing mod, do you mean cutting the grey wire to change ignition curve to yz spec.? The cams are for yz and wr nothing different. I imagine they are along the lines of yz. I can't think of anyone that would want to change there cam timing to wr spec; maybe some for really tech. riding. If i was running too lean would it be the pilot jet or the needle? I'm pretty sure needle is stock, pilot is stock(42), main jet is 168. I plan on switching to 45 PJ but I don't know if I should switch to YZ spec or just raise the one I have by one clip. I would appreciate any help you guys can give me.

All your questions are answered here:

https://www.thumpertalk.com/forum/showthread.php?t=440631

[DB_Cooper]

"Consequently, what does a plug look like if the bike is running rich? I think mine is running lean "

THE YAMAHAS ARE KIND OF A PAIN TO GET PLUG CHECKS ON BECAUSE OF ALL THE CRAP YOU NEED TO REMOVE TO GET TO THE PLUG. I LEAVE TANK-SHROUDS-SEAT UNBOLTED. INSTALL BRAND NEW PLUG, FIRE UP BIKE AND TAKE A COUPLE FAST RUNS ON A ROAD TO GET HEATED UP TO OPERATING TEMP. KILL THE BIKE AND IMMEDIATLY REMOVE-CHECK END OF PLUG. IT SHOULD BE A NICE TAN COLOR.? IF IT STILL LOOKS "NEW" ITS TOO LEAN-IF IT IS BLACK OR HAS WET GAS-ITS TOO RICH.?

DO A SEARCH ON THE THUMPER FORUM FOR JETTING SPECS WITH ANY MODIFACATIONS YOU HAVE DONE TO YOUR BIKE. THEY SHOULD GET YOU IN THE BALLPARK AND YOU'LL PROPABLY HAVE TO "FINE TUNE" FOR YOUR AREA/ALTITUDE/ETC. REMEMBER THE YAMAHAS WILL "OVER-RICHEN" REALLY EASY SO GO SMALL JET CHANGES-1/4 TURN IDLE SCREW ADJUSTMENTS-ETC AT A TIME.

NOT FUN-NOT EASY BUT WHEN YOU GET IT DIALED IN DEAD NUTS, YOU'LL WONDER HOW YOU EVER RODE IT "STOCK" !!!?

[jays22b]

"Consequently, what does a plug look like if the bike is running rich? I think mine is running lean "

THE YAMAHAS ARE KIND OF A PAIN TO GET PLUG CHECKS ON BECAUSE OF ALL THE CRAP YOU NEED TO REMOVE TO GET TO THE PLUG. I LEAVE TANK-SHROUDS-SEAT UNBOLTED. INSTALL BRAND NEW PLUG, FIRE UP BIKE AND TAKE A COUPLE FAST RUNS ON A ROAD TO GET HEATED UP TO OPERATING TEMP. KILL THE BIKE AND IMMEDIATLY REMOVE-CHECK END OF PLUG. IT SHOULD BE A NICE TAN COLOR.? IF IT STILL LOOKS "NEW" ITS TOO LEAN-IF IT IS BLACK OR HAS WET GAS-ITS TOO RICH.?

DO A SEARCH ON THE THUMPER FORUM FOR JETTING SPECS WITH ANY MODIFACATIONS YOU HAVE DONE TO YOUR BIKE. THEY SHOULD GET YOU IN THE BALLPARK AND YOU'LL PROPABLY HAVE TO "FINE TUNE" FOR YOUR AREA/ALTITUDE/ETC. REMEMBER THE YAMAHAS WILL "OVER-RICHEN" REALLY EASY SO GO SMALL JET CHANGES-1/4 TURN IDLE SCREW ADJUSTMENTS-ETC AT A TIME.

NOT FUN-NOT EASY BUT WHEN YOU GET IT DIALED IN DEAD NUTS, YOU'LL WONDER HOW YOU EVER RODE IT "STOCK" !!!?

sounds good this way. its a ture way off seeing whats happening in the cylinder. i was going to use the exhust pipe to check but the spark plug would be the best way as its in there... unless u get it tuned by a pro this is a good back yard method..