I did not expect any response to this request from a different Thread but maybe an unbiased opinion may sprout out here...
Hello everyone I am an early bird when it comes to small engines from the late 60?s
I wish to address the people I have spoke with in all the forum but the issue I have encountered on the
YXF450 and the red hot pipes, surprises me
I see that there are many that say this is a normal thing for this machine; I can not disagree with the masses.
But one thing I do remember an old mechanic told me was that,
"When a machine runs lean it runs mean, but like the short song, Not for Long."
Everyone shrugs off the red hot pipes as if it is OK! Why?
It contradicts many things I learned from race drivers and engine builders.
Does this machine and others have the same characteristics?

I would appreciate an input on this matter before I start scrathing out brand names for a new purchase.

 

I don't own that bike, but I know I would not settle for that. If this is "normal", I would be selling it to one of those "normal" people and buying something else. Glowing pipes has NEVER meant anything good.

 

My take on this.
Just because the pipe is red does not mean it's lean. The pipes on these machines are very thin. They make them that way to keep the weight down. After all, it is a race machine.

I like to keep my EGT's around 1,400 or so. 1,500 if I can watch it like a hawk and make sure it's not going any higher.
At 1,400 a thin pipe is going to get VERY red. You can look up a chart on the net that will show you what steel will look like at various temps.
If the pipe deal bothers you, you can do two things:
1. Richen the thing up.
2. Heat wrap the pipe.
#2 is the best thing to do. It will kill off radiant heat and keep the flow up and give a smige more power.

All in all I see it like this. You don't see brand X 450's dropping like flies from burnt pistons. If they were lean, that's what you would see. If you like the glow, heat wrap the pipe and go have fun.

 

Yz 400/426/450 all run hot. It is normal for them to be red. Same with the yfz450. The yz's you cant even let idle for more than 2 minut. My pipe glows "BLUE" on my yz426 motor and im running rich and im lucky if i can run it for 20minuts with out the radiator boiling over and i run a pwr radiator and engine ice[img]i/expressions/face-icon-small-shocked.gif[/img] My oil goes to crap after 2-3 hours.

 

Yes, the red glowing headers on the new ho 450's will glow red if the bike is stationary or ridden very slowly. This is the new norm and is perfectly OK. Like DrTurbo stated, the headers are made of a thinner stainless than in the past, and as such glow that much easier. Additionally, these are set up to go fast. After one lap following my son around the local play track, the fan is on and the engine is warm. My son is just 8 now, and rides pretty slow on his mini. On the other hand, I can burn multiple laps at a serious pace on the same track and the fan usually doesn't even kick on. All the 450s seem to be the same, bikes, quads, any manufacturer. Aftermarket headers accentuate the glowing even more usually. Just for kicks, I jetted my pilot blatantly on the rich side when I put an aftermarket pipe on, and the new header still glowed some after she was idling for a few minutes.

 

Thank you all for being kind enough to explain the characteristics of this model.
I assure you that I have no intentions of degrading this model. I was just as curious as any newbie that purchased one. I am not in that category as of yet. I am still making the wire from stretching a penny.

I was comparing it to the new experimental Harley they were showing on the science channel.
This was a concern that the Harley engineers were focusing on. They were using different designs in air capturing.
Hard test in the middle of the desert at 12:00 hi and letting the machines idle.

450 Sounds like a great machine if it can stand all that heat and not break apart.
But I bet if one of you have discovered a way to prevent this, in any condition, you best get a patient lawyer ASAP and make some money to follow.

I ran across this on the internet that may be of interest some might already know of this info

Reading Sparkplugs and what causes some conditions

 

TommyA300, You can easily get a properly colored or even blackened plug but still have the glowing header. It really has a lot more to do with the head pipe design than how the motor is running. I was flipping through a new dirtbike rag the other day and came across a blurb about this very thing being normal on the bikes too. I can't remember which mag, but I was looking for the "super secret Keihein trick" advertised on the bottom right of the front cover, and the mag had a lot of top ten all time lists. Maybe seeing it in print would calm your worries somewhat?

 

Scooter thank you what I have been seeing more and more threads asking the same question.
I do not own one, if I did I would be working on a solution no matter what is in the magazines.
No disrespect mind you!
I seen hype in allot of readings and years later it was proven incorrect. But once the horse is out of the barn what do you do after that?
My main concern is that if this is the trend of what the manufacturers are claming it is ok.
This is contrary to all race professionals that had clamed in the many years of racing. Red headers is not a good sign.
Besides this is happening when the machine is sitting idling... I believe it is not the carb jetting, it is the cooling system not designed for the machine, to have that machine sit there idling for a few minutes. This should be a concern. Harley designers strugled on their new water cooling system and tested it in the extreem heat in a desert two gus would run the hell out of the bike and then park them and let them idle for hours. WHY did HD do this because they are concerned and know that heat, extreem heat, kills engines.

I would need some evidence that they, the manufacturers, have stumbled on a new material compound that they can use on the space shuttle tiles, which they employed in there special design.

All I can do is sit back andwait for a recall on these machines. It may take years but who knows. I may be incorrect becaus I can not see the big picture?

 

I agree with it being in the valve timing and thin wall pipes.
As far as the harleys go, its comparing apples to oranges. Harley owners arent interested in getting horsepower( that why they get a harley), but are interested in how the pipes shine up. Want to see a pissed off harley owner? Jet the carb a bit lean, have the pipe turn permenetly blue, and watch the fireworks. They couldnt care less about performance...its all image. Thats why the Harley co. is testing the pipes...too many claims in the past, and they want to avoid it happening again.
My 2 cents

 

I understand where you are coming from Apples and oranges in their categorys, but they are still a fruit.
An engine is and engine any which way you cut the pie.
There has to be a fix for this not a bandaid fix either.
I was not comparing people?s characters I was mentioning reliability factors HD always had that thorn in their side for years. Also with an HD I remember if the timing was not right on with respect to front and rear cylinders the pipes would blue in a 5 sec period.
I was reading something on overheating and there was something mentioned if the timing is to far advance.
In this case it only happening when the machine is sitting still at idle.
Can it be possible that at an idle the timing needs to be retarded more and the swing to full advance at higher R's be greater.
I was wondering if anyone had ever tried letting it idle thru a full tank of fuel and see if it would still uphold performance.

Obviously when anyone starts there machine they want to get on the get go ASAP and this would be the factor that saves this machine from self destruct.
Open opinions is needed here never want to start a war or degrade a machine of any brand.
Thank You guys for your input!