RM400T frame crack?

[pmcburney]

I had a ball at the Conondale Classic last weekend on the RM - it went like a scalded cat the whole time and I couldn't be happier with the bike and the money and time I've spent on it so far...

After giving it a decent wash and going over, I've noticed a crack in the powder coat on the frame that could be an issue:



For clarification, this is the junction of the LH rear downtube and the bottom (horizontal) tube adjacent to the LH footpeg.

Is this a known failure point on these bikes?
Is this an issue I should address straight away?
Are there any other known failure points I should be aware of?

Any info greatly appreciated...

[LWC82PE]

This is the number one reason i avoid and would not recommend powdercoating a frame.
Better get it fixed asap before moisture gets in that crack.

[pmcburney]

Yeah, I'm no fan of PC myself - this was done by a previous owner.


Only way I'm gonna tell if it's the coating or the tubing is to clean it back to bare metal...

[sleepy]

Common place to crack.
Powder coat will need to go around the repair and a gusset may help as the metal fatigue caused the crack so spreading the load will help stop it happening again.
If you don't repair it will crack all the way through and potentially get a bit ugly with the footpeg close by.   

[rocketfrog]

Powder coat for show, paint for a pro. Get it magnetic particle tested, you can see a crack through non conductive surface finishes (reduced sensitivity with thickness of coating)

[sleepy]

Powder coat for show, paint for a pro. Get it magnetic particle tested, you can see a crack through non conductive surface finishes (reduced sensitivity with thickness of coating)

Really, Mag particle testing is normally for cracks you can't easily see with the naked eye like a car crank or conrod to avoid a failure but the frame has already failed and if left the crack would soon be all the way through.

[Short Stuff]

One of my PEs cracked in a similar position. I had it re-welded with a gusset added.

And I  agree with other responders, I  don't like powder coating (in general), because it's difficult doing running repairs.

[pmcburney]

Thanks for all the advice - I've taken the motor out and I'll be getting it welded/strengthened shortly to have it ready for Kyogle.


The powder coat will stay for the time being.
Sure it's not ideal but the bike is a rider, the coating is now damaged and I'd only be marking up a new paint job anyway...

I'll post up results of the repair.

[Oldfart]

its a common faulty with 250 and 400 Rm T models ....I had to fix both the of mine many years ago. I think there is a thread on how I fixed the problem and solved the problem

[LWC82PE]

Interested to see the bracing solution. Haven't heard of it happening to PE's. Maybe it only happens with MX type jumps and heavy riders?