Hey everyone i know this might be a really stupid question but when i hold my Z-400 wide open the pipe comming of the manifold gets red hot for about 4inches. This only happens when i hold it for like 20 seconds. At full thgrottle for like 5seconds it still gets red for about an inch. This means that i need to jet it higher yet right? I never did this untill i had my valves set however. Thanks

 

Go out and run your z hard.....then hold it wide open for about 5 sec.....and shut it off.......pull the plug and tell us the color of the electorde(inner part)........should be paper bag brown.....Sounds like you are too lean on the top side.....

 

alright thanks for the help ill give it a show , just wondering if its normal to have the headpipe turn alittle red?

 

The 05 and 06 z's come with titanium header pipes, like the yfz. The titanium is a lot thinner and lighter than steel, but the same strength. You may be lean, but it is perfectly normal for these pipes to get red as they are thinner. I already knew about this but my dealer told me too when I bought my z because a lot of people had been concerned. If you had the steel pipe, than you'd probably have something to worry about. You'll notice they also throw off a lot more heat than the steel ones. A friend of mine with a yfz wrapped his with header wrap. You can get this at an auto parts store, it's the stuff race car drivers wrap their headers with.
I noticed more of a problem with the yfz than the z as far as the heat on your leg.

 

Yea it definatly gets hot because i have a couple of pairs of jeans with holes burnt in them. Anyways it was running a little lean with a 130 dynojet in it so i put a 134 in and it is much better. Thanks for the help

 

My King Quad pipe glows red if I let it idle awhile, I can't see it when riding so I can't say if it does it then. I have head of pipes plowing on quads/bikes before but never saw it until my KQ.

 

EFI small engines, quads and motorcycles, are setup to run lean to comply with emission standards. The important thing to remember are the egt's "exhaust gas temperatures" must not exceed 1250 deg F for sustained periods of time. If you do exceed 1250 for prolonged periods piston meltdown can occur. I have had guys telling me they have run their engines at 1300 without problems, all I can say is 1250 is a safe temperature anything higher is risky.
For the people seeing a red exhaust at idle you can do a couple of things.
1, measure the temperature using a thermocouple or an infrared temp indicator, or
2, bring the engine to operating temp, remove and clean the spark plug then reinstall. Let it run at idle until the pipe glows red, let it idle for 10 mins or so. Shut off the engine and check the colour of the sparkplug, if it's white it is too lean, it should be rusty brown.