And Another Broken W Arm

[Tycho998]

Last run of the season and I noticed two hairline fractures on the W arms, same place left and right side. Reading other posts, this NOT the place where others are having theirs break, correct? Looking closely at the fractures they seem to be rusting from the inside out. Looking at the pictures posted by NY AttakGT, his also appear to be rusted from the inside out. I do not think this is a break that can be repaired. Has anyone actually used the '08 arm in a '06?

 

[rx1warrior]

Those arms are just PATHETIC to have in a $15k sled. Mine broke 2 times in 4500 miles. 08's will fit and they are a bit beefier. I just welded mine and reinforced it so it should be good for a while.

 

[welterracer]

That is actually an odd place for them to break..

 

[LJ 452]

You should be able to repair the W-arm regardless of the fracture location. As for the rust, raw steel begins to rust the second it's exposed to the atmosphere. Flash rusting can occur even on a dry sunny day. Given what the sled is exposed to it's no surprise that the fracture looks the way it does, from a corrosion standpoint. As for the fracture location it does seem different from others. Mine had about 5-10 cracks like yours but can’t remember the locations as I was just welding them up and looking for more. I added reinforcement plates before the Hygear was installed and nearly 4000 miles latter it was fine. Do you find that the sled bottoms out often?

 

[Tycho998]

It used to bottom out at the start of the season. I got the shock rebuilt and revalved. The mechanic said the oil was like water, it was that bad. That was almost 6000km ago. I can think of only one serious impact. I was playing on a hydro line when I came across a open creek. I had a choice full throttle and hit the other side or brake and put the nose into the creek...I hit the throttle. While I made it the back suspension dropped and it the far side very hard.
As for welding. Wouldn't the strain on that tube probable crack around a weld that went the circumference? I image that if I got a crack there, the lower tube is probably ready to go also.

 

[Budweiser]

Just get the 08. Same thing happened to my 06 and the 08 is much much beefier. I got mine from Port for a little over 300. It comes with a new limiter strap as the tube it wraps around is bigger and the old strap won't fit.

My 06 lasted 10,700 miles, I'm sure the 08 will last much longer. There are pics on here somewhere of the 08. Try the search. I can takes pics of mine if needed as the skid is still out.

 

[SumpBuster]

A while back, someone from Sweden or somewhere posted all the gusseting he did. I copied that and a few others adding quite a bit of metal. Just grind the crack, weld it, and gusset or lay a piece of metal and weld over it. I've had good luck welding RX1 arms with just a 110 volt flux core welder. The last one was a catastrophic failure, broken in at least 10 places, so the track came forward and the slides hit the front sprockets...the guy 'thought' something didn't feel right..LOL...what a mess. He kept tightening the track so it wouldn't derail, without ever noticing the broken a arm.
I welded it up while waiting for a new one...he wanted to ride. He also had a broken front spindle and didn't know it...figured the spindle can't fall out, so he kept going for two weeks with that too...he rides kinda rough....lol.

 

[SumpBuster]

And I doubt that fracture occured from one big bump. I think it's more of a time element to start the crack. In my experience if I hit something bad, it got broke right away, or was good for the long haul. I also think vibration plays a role..frequencies, track clip vibrations, etc over time, and then the big bump breaks the weakened parts in half.

 

[apltx08]

Here's pics I posted of my '08 pivot arm on another topic...the life of a pivot arm is only as good as your MONO shock calibration, meaning your riding style, spring rate and proper SAG and valving, and get your shock oil changed and re-charger every year, don't forget you only have 1 shock doing all the work, it takes a lot of BEATINGS during a season. My buddy has 13.000kms on his '05 RX1-ER with original pivot arm and still going, 1 last thing MONO = GROOMED trails, its not a DITCHBANGING suspension it doesn't like to much abuse.

http://www.ty4stroke.com/viewtopic.php? ... highlight=