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View Full Version : Problems with brand new YFZ450.


Vem YFZ450
06-25-2006, 03:53 AM
I just got my YFZ 450 delivered today and Im already having problems.

The head pipe is glowing red and is burning hot when I turn it on.
The engine stop running unless I hold the throttle a little down.

Any experts on this?

Could it be a jetting problem?
GPracer2500
06-25-2006, 04:17 AM
The excessive heat and poor idling could both easily be carburetion issues (sounds lean). Many (most or even all?) bikes these days are jetted lean straight from the factory for emissions reasons.

As far as not idling, turn up the throttle stop screw a bit. It is probably a small, black knob with large knurls. Turn it clockwise to raise the idle speed. That doesn't do anything as far as adjusting leaness/richness but it should help with the idle speed.

Is the quad completely stock? Have you touched the airbox or spark arrestor?
Vem YFZ450
06-25-2006, 06:06 AM
Originally posted by GPracer2500
The excessive heat and poor idling could both easily be carburetion issues (sounds lean). Many (most or even all?) bikes these days are jetted lean straight from the factory for emissions reasons.

As far as not idling, turn up the throttle stop screw a bit. It is probably a small, black knob with large knurls. Turn it clockwise to raise the idle speed. That doesn't do anything as far as adjusting leaness/richness but it should help with the idle speed.

Is the quad completely stock? Have you touched the airbox or spark arrestor?

Thank you for your reply and time.
I really dont know much about mechanical issues.
I just started learning about quads last year.

If the bike is lean? Will I have to make some changes to the jetting?


And yes my bike is stock.
zeppelin
06-25-2006, 07:07 AM
all headers will glow red at night on the newer bikes, thats normal. but if you still would like to make some carburation changes, i would go one size up on the pilot jet. if you need help with jetting terms and techniques check out my thread in the how to section http://www.exriders.com/vbb/showthread.php?s=&threadid=221872
badass300ex
06-25-2006, 01:29 PM
Take it back to the dealer if its brand new let them fix it.
Caseys 300ex
06-25-2006, 02:17 PM
Take it back and buy a Honda;)
badass300ex
06-25-2006, 02:59 PM
:D
04blackyfz450
06-25-2006, 04:03 PM
yepp what most others said, it will glow red and tats normal, the yfzs come lean
YFZ450Ridr
06-25-2006, 06:28 PM
Originally posted by Caseys 300ex
Take it back and buy a Honda;)

people like you are worthless. he has an issue with his quad and you come in and say buy a honda. get off the site or learn to keep your mouth shut.

any way, i go over to yfz central some times and everyone over there says that the yfz is jetted very lean from factory. mess with the fuel/air screw, that might help out.
Caseys 300ex
06-25-2006, 08:59 PM
Hey im sorry for what i said. Im a big fan of yfz 450s. From what i heard in the past yfz's have a tendency to glow red. So if i were you i woudl take it to the dealer and see if they could fix your bike for ya. but once u get that done u should have a heck of a bike.;)
Caseys 300ex
06-25-2006, 09:01 PM
So how does a bike thats to lean make the pipe glow red?
zeppelin
06-25-2006, 09:07 PM
motors always tend to run hotter under lean fuel conditions ;)
GPracer2500
06-25-2006, 09:07 PM
Originally posted by Caseys 300ex
So how does a bike thats to lean make the pipe glow red?

Lean = runs hot
rich = runs cool(er)

ETA: Zeppelin beat me to it!
2StrokeGod
06-25-2006, 09:20 PM
You at least need to go with a 165-168 main stock is 155 and go up 1 on the pilot and the pipe will always glo red and its normal
Caseys 300ex
06-25-2006, 09:34 PM
Thanx GPracer2500 and zepplin for answering my question
krt400ex
06-27-2006, 04:28 PM
Originally posted by Caseys 300ex
Take it back and buy a Honda;)

:D
krt400ex
06-27-2006, 04:30 PM
Originally posted by Caseys 300ex
So how does a bike thats to lean make the pipe glow red?

because it runs hotter. when metal gets very hot it starts glowing red
Toadz400
06-28-2006, 11:42 PM
Originally posted by Caseys 300ex
Take it back and buy a Honda;)

:rolleyes:

YFZ's come lean from the factory. Need to richen it up a little bit, but if you don't know how to do that go to YFZCentral and do a search on jetting.

And as for the idling problem, a lot of them seem to be set very low from the factory also (I didn't have this problem). It's the black knob that you can turn (DON'T turn the TPS switch, that will cause nothing but problems), turn it clockwise to increase the idle.