Author Topic: AF Not Up to Job  (Read 5131 times)

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Offline streetsleeper

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AF Not Up to Job
« on: January 17, 2019, 01:35:52 AM »
I heard it was a good mod...

Offline umberto

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Re: AF Not Up to Job
« Reply #1 on: January 17, 2019, 02:09:53 AM »
That's one of the challenges of aluminum.  If you weld on it, it loses its temper and becomes soft.  The factory bikes gain theirs back on the long boat ride from Japan, but most conversion do not get that kind of break, nor do some builders properly brace the frames and head stays.  KTM is correct to use steel; it's more expensive to manufacture, but it doesn't mind a little heat.
Perhaps I have a dirt bike addiction?

03 KX 250/88 KX 525/2017 KX250F - Goliath
17 KX250F/04 KX250
04 KX 250 - Lunchbox's Bike
05 KX 125/144

Offline sandblaster

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Re: AF Not Up to Job
« Reply #2 on: January 17, 2019, 03:41:15 AM »
Umberto is right.
Look at the frame and where it broke.
It broke there because the engine being locked into the swingarm pivot pin area tries to rotate off that pin in a clockwise manner looking at the bike from the right.
The lower and forward mounts can't prevent that rotation very well due to their location.
That means that the upper mounts have to be in a position to keep the engine where it needs to be.
I have seen all sorts or ways to do the head mounts...
Most are poorly thought out and actually increase the chances of a frame break.
If done correctly, a conversion will take anything you can dish out...
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Kawafornication

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Re: AF Not Up to Job
« Reply #3 on: January 17, 2019, 04:56:32 PM »
Failing to prepare is preparing to fail!!!

https://www.youtube.com/watch?v=YnREVb33zx0

Offline streetsleeper

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Re: AF Not Up to Job
« Reply #4 on: January 17, 2019, 11:56:50 PM »
It's not a very good advert for the Australian company Ozweld. After seeing this I wonder how many potential customers took their business elsewhere?

Offline kxpegger

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Re: AF Not Up to Job
« Reply #5 on: January 18, 2019, 03:33:24 PM »
It's not a very good advert for the Australian company Ozweld. After seeing this I wonder how many potential customers took their business elsewhere?
My AF was built by Service Honda. I bought it in 2009 and it was built on a 2008 KX450F frame. The bike is not a garage queen and I beat the snot out of it in the Nevada desert. No signs of failure yet! The picture you provided does not indicate that AF conversions are inherently faulty but that this particular conversion you show cased was. 
North Las Vegas

"05" RMZ450, "08" KX500AF "11" KTM 450SX-F "12" KTM 250SX "15" KTM450SX-F

Offline streetsleeper

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Re: AF Not Up to Job
« Reply #6 on: January 20, 2019, 05:00:33 AM »
It's not a very good advert for the Australian company Ozweld. After seeing this I wonder how many potential customers took their business elsewhere?
My AF was built by Service Honda. I bought it in 2009 and it was built on a 2008 KX450F frame. The bike is not a garage queen and I beat the snot out of it in the Nevada desert. No signs of failure yet! The picture you provided does not indicate that AF conversions are inherently faulty but that this particular conversion you show cased was.  
kxpegger - agreed! I love some of those AF conversions. This one's a good 'un on YT: https://youtu.be/Kk9zAtONO_U
Funny thing is, the one that really stokes my interest is the BRC engine in the KTM chassis. Their engine fits the 250/350 06-16 chassis, but then again that's a SF too. I didn't mean to "showcase" either, just a bit gobsmacked. When something like that happens you can see the potential for disaster and just hope the rider got out of it without injury...
« Last Edit: January 20, 2019, 05:15:43 AM by streetsleeper »

Offline 1901306708

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Re: AF Not Up to Job
« Reply #7 on: January 20, 2019, 05:05:33 AM »
They are not all created equal is an understatement! It’s unbelievable how strong the service Honda frames are.