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ish416
11-07-2009, 06:10 PM
Had a good day or riding today but noticed that my completely stock kfx450 would occasionally backfire.

I just thought it odd but kept riding. A few hours later, as soon as I get back to the house, another backfire and then I noticed the quad had gotten much louder.

Turns out the exhaust header cracked right where the bend is. This is the second time this has happened to me.

Any ideas on if the issue could be the quad or did I just get two bad headers?

I run it with the airbox lid on and the spark arrestor in.
KFX450Rrider490
11-08-2009, 06:46 AM
that happened to annother member on here i wish i could help you but i have no clue how or why that would happen?
BEARAZZ
11-08-2009, 05:01 PM
It has happened to me 2 times also..
BLU82
11-08-2009, 05:05 PM
It happened with me. How many hours did you have on them? I believe they crack because the titanium eventually gets stressed from getting so hot and then cooling over and over.
ish416
11-08-2009, 08:52 PM
I would say its somewhere between the 40 - 60 hour mark.

Any idea if Kawaski will cover it since the quad is out of warranty. It's obviously a defect of some sort.

Otherwise, anyone had any issues with aftermarket head pipes?
BEARAZZ
11-09-2009, 05:34 PM
they covered mine , but mine was still covered
MtnEX
11-11-2009, 11:06 PM
No issues with the header on my Jardine RT99 system.

This header is stainless, which weighs a tad more, but seems worth it for durability.

The stock can weighs like 10-11 lbs, so I dropped like 7-8 lbs there to MORE than make up for it.
woodsracer144
11-18-2009, 12:02 PM
Originally posted by BLU82
It happened with me. How many hours did you have on them? I believe they crack because the titanium eventually gets stressed from getting so hot and then cooling over and over.

TI is a really fogiving metal.. in my welding class we too a chunk of 1/16 thick and it was 3inches by 2 inches and we took the torch and ran it acrost the end ( like you would cut off a half an inch) and it would just get cherry red and then bend over and it was really hard to just cut. as soon as you took the torch off it then it would cool redicioulsly fast normally the cherry glow stays around for a little while and on the TI it went away right away...

i doubt that its from getting hot.. how many hours are on it...post a pic up of it... if you can. thanks
ish416
11-20-2009, 08:21 PM
Here are a few pics of the header, sorry about the crap quality. My cell phone sucks.
ish416
11-20-2009, 08:23 PM
And another.

Both of the headers cracked in the same place the same way.

The first time the crack was about a half inch longer.

The crack is located on the bottom of the header.
woodsracer144
11-20-2009, 09:17 PM
is this will a all stock exhaust system? what mods do you have? i had this happen with a hybred before... did it ever get cheery red?
ish416
11-21-2009, 11:07 AM
My quad is completely stock, The same as the day I bought it.

I run it with the airbox lid on and the exhaust baffle in.

And yes, I ride it hard enough that the exhaust will glow red though, it is only visible at night.
KFX450Rrider490
11-21-2009, 02:32 PM
the glowing exhaust is completly normal these bikes run hot very hot!
woodsracer144
11-21-2009, 08:04 PM
Originally posted by 300exrider490
the glowing exhaust is completly normal these bikes run hot very hot!

this is the reason that i blew my exhaust out... think of it as every time you heat that babby up and let it air cool it gets softer and softer and then if you heat it up and spray water on it it hardens it... so if its glowing red it means your motor's EGT is too high or the metal in your headder is really thin... i dont know why these things dont run a pyro so you can check EGT because that can be part of the reasoning behind not lasting at all..

how ever i find it strange that your quad would backfire at OE specs. how much time is on it what rating of fuel do you use?
ish416
11-22-2009, 10:22 AM
Every quad/bike that I have seen with a TI header glows red when you are in high rpm's at night. Mine is not noticeable during the day.

The backfiring was caused by a small crack in the exhaust. Which later became the crack in the picture.

My quad was running fine and then started backfiring occasionally. I at first thought it might have been bad gas or a fouled spark plug. Then it backfired again and I could hear the exhaust leak. Once that happened I knew exactly what it was.

My quad has about 120 hours on it and I run fresh 93 octane.