Question about 2001 Yamaha YZ 426 F

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Header pipe turns red hot why is carb. to lean?

Posted by Anonymous on


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Hi, Anonymous a YZ is a motocross bike designed to run flat out that being said if you are strolling down some scenic trail at a slow pace or letting the bike idle for a few minutes your header pipe will turn cherry red, why you ask? It is not a street bike, it is designed for competition and weight is a major factor all necessary components are of the smallest and lightest design necessary to maintain performance under extreme conditions ie. small radiator and inside frame oil reservoir that doesn't get cooled, the majority of your riding needs to be at high speed. For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
02 YZ426F Header Pipe Glows Red 4Strokes com
2002 Yz426f Header Pipe Turns Red YZ 400 426 450
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

Posted on Aug 04, 2016


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Posted on Jan 02, 2017

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SOURCE: yzf 450f `04 exhaust pipe glows red --believe it to be lean burn

They will all glow red when you let them idle for a couple minutes. The timing is retarded at idle I believe. Once reved up they will cool off. I figure best to give them a little rev once and a while to help prevent this.

Posted on Mar 19, 2009

ollie reece
  • 1167 Answers

SOURCE: Exhaust header pipes getting glowing red hot

the pilot jet is too only make the bike idle so it wouldnt be this is the engine have lots of oil in the engine

Posted on Oct 01, 2009

Testimonial: "I haven't thought of that but I will put a little more oil in it and try it again. Will let you know the results later. Thanks"

  • 278 Answers

SOURCE: hi i have oil or gas coming out the header pipe

Do a compression check on all cylinders. This may need rings or has a sticky intake valve

Posted on Oct 15, 2009

Testimonial: "thanks mathewsdl on the fzr 1000 very helpful"

  • 7 Answers

SOURCE: wr426 getting really hot, header pipe is bright

I would check your coolant first off. Your bike also may be running a little rich (too much fuel) which can cause greater heat. I would try adjusting the little black knob that sticks out of your carburetor, this will adjust your air-fuel mixture. Be careful though, adjusting too much at one time and then riding it hard could damage your bike, i'd adjust it little by little and then ride a bit after each adjustment. See if that helps you work out this problem. good luck

Posted on Nov 20, 2009

  • 677 Answers

SOURCE: 04 yz250f pipe at motor glowing red hot

Any reason you had to change the jetting??New pipe,Intakes.?But,even though you may have it a bit rich on idle the pipes WILL get very hot,very quickly without some sort of air flow over the front of the motor and radiator.At the very least,have a strong fan blowing directly on the front of the motor if you are going to let the bike run and you are not riding it.I have seen the white plastics in front of the radiator distort from the radiant heat.Don't idle them for in more then 20 seconds.It can do heaps of damage.Ride the bike and see if its running well.When you stop,turn it off.All the yz and wrf will get very hot at idle.Hope this helps

Posted on Jan 17, 2010

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I have a Honda xr 100 dirt bike when running exhaust seems to get red hot in front pipe on bike is there a problem

Hi, Shaun on a 2 stroke no on a 4 stroke yes and the usual suspects are:
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What coud be making my pipe got red hot

Hi, the pipe getting red at the header is caused by the fuel mixture being to lean or the ignition timing being too retarded. Check the induction side of the engine for air leaks and the carburettor for blockages etc. Check the ignition timing.
Hope that helps Matt...

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Head pipes are glowing red hot at stops

If your pipes are glowing at stops it's because you are running too lean. Running that lean will weaken the valve springs destroy your exhaust gaskets, and destroy your pipes as well. It's an 2002 so rejet the carb for whatever your combo is. Make sure you are running a #48 pilot jet and if the mixture screw has been tampered with , it should be about 1 1/2 turns out.

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Immediate overheating... with in 1 to 2 minutes of warm up... bad enough to make the header pipe glow red.

It sounds like the fuel mixture is running extremely lean for some reason. Disassemble the carb and clean out the jets. Inspect any rubber parts between the carb and the intake. Make sure the intake manifold doesn't have an air leak.

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Exhaust header pipes getting glowing red hot

the pilot jet is too only make the bike idle so it wouldnt be this is the engine have lots of oil in the engine

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2000 Yamaha TW 200 lacks power, has a high speed miss. Dealer can't find, has thrown in the towel. I am a professional MC mechanic with over 30 years, I have tried every thing I can think of. Same symptoms...

Your timing may have skipped a tooth. This causes the glowing pipe. Ther are 3 positions that look like tdc. The flywheel has "I" "T" and range marks. This can be confusing. Put the "T" on the mark and you will run perfect. If not you can set it up one tooth or down one from that position. One setting makes the bike run like ****, the other one is barely noticeable more or less power. You may have to play with it a bit to get it right. If your pipe still glows after redoing your timing then your can change up your jet to a higher flow. Usually a performance filter will lean out the mix causing a red pipe. To much fuel just fouls the plug. I deleted my filter box and put a cone K&N filter. I had to jet my carbs to compensate for all the extra air flow. The bike had more power after I did this. The main jet I used was 127 or some where around there, the stock jet is 115 I think.

To much gas would never make you glow. Timing being off or being to lean will.

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