billet rod failure

[vegasboy]

Hey guys, wanted to show you some billet destruction. This happened while slowing down to get into the turn lane on my motorcycle. And no, it was not due to lack of oil. Bolt failure is suspected at this point. I didn't know you could break one of these!? 420cc predator aftermarket rod not the stock one for those who are new to this and not sure what there looking at.

 

[landuse]

Ouch!! That is one way to vent your block

 

[vegasboy]

Lol, i know. That rod has hundreds of miles on it. Totally unexpected. $150 bucks for it too. Shouldn't had happened. Maybe bolts were too tight?

 

[Mulletcar88]

Aluminum has a more finite life cycle than steel, if it had hundreds of miles on it maybe it was it's time to go.

 

[itsid]

too tight bolts and maybe ignition a little bit early just to stress crack a little bit sooner

On your motor cycle?
that means the shrapnels went towards the underside of the saddle?

I hope you're okay!

'sid

 

[vegasboy]

My knee was burnt by something, and im thankful the gas tank took part of the hit for me. Nothing serious.

 

[vegasboy]

Here is the bike it happened on.

 

[crazykart]

That makes me think of back when I wanted to put a snowmobile engine on a motorcycle.

 

[vegasboy]

Well clearly you shouldve. There is a guy in vegas that has a snow mobile engine in a very beautiful motorcycle. I only saw it on someone's phone. But awesome none the less.

 

[crazykart]

I still do, just a matter of money and time.

 

[OzFab]

Well, that's an eye opener, we usually tell people to use a billet rod to avoid such situations

Tell me, you mentioned the engine has a few hundred miles on it; were a large majority of those miles at high RPM?

 

[vegasboy]

Yep, around town low rpms, on the freeway high rpms.

---------- Post added at 08:44 PM ---------- Previous post was at 08:41 PM ----------

The stock engine had about 3000 miles on it before billet rod install. And less then a thousand on the billet rod.

 

[commonrail]

What kinda damage did the crank have on it?

 

[vegasboy]

No damage at all. Seriously...

---------- Post added at 12:26 AM ---------- Previous post was at 12:04 AM ----------

No scoring at all on crank. New revelation!!! We just saw the exhaust valve is bent suggesting it warped, got stuck open and hit the piston!!! Causing a shockwave to the rod.

 

[landuse]

No damage at all. Seriously...

---------- Post added at 12:26 AM ---------- Previous post was at 12:04 AM ----------

No scoring at all on crank. New revelation!!! We just saw the exhaust valve is bent suggesting it warped, got stuck open and hit the piston!!! Causing a shockwave to the rod.

That might have done it...

 

[OzFab]

That could do it; is there any marks on the piston suggesting it hit the valve?

Valve bounce may also be responsible for this...

 

[vegasboy]

Very slight mark nothing major.

---------- Post added at 12:56 AM ---------- Previous post was at 12:55 AM ----------

I also have heavy duty springs also.

 

[KartFab]

So is it good to upgrade valves while doing all of the other performance upgrades then?

 

[Zombient]

So is it good to upgrade valves while doing all of the other performance upgrades then?

http://www.diygokarts.com/vb/showthread.php?t=30930

Bottom of the thread.

 

[OzFab]

Very slight mark nothing major.

That's enough...

I also have heavy duty springs also.

Well, that rules out the "valve bounce" theory but, as there is a mark on the piston, it doesn't rule out contact; a piston moving at 6000rpm will create enough force to easily bend a 5'16" valve stem...

So is it good to upgrade valves while doing all of the other performance upgrades then?

As mentioned in this thread, any performance upgrade will potentially shorten the life of an engine; I once heard about a $70k drag car engine that drove less than a mile before "expiring"...

The simple fact is, the more mods you do, the more mods you need to do to keep up with what's already been done, ie: there's no point using harder valve springs on stock valves or a stock cam on an engine that revs to 7000rpm; eventually, something will touch something else &... well, you know the rest...