Subframe modification/replacement

[Fourth_Floor]

Anyone have any info about changing the subframe over to a KTM subframe? I seen someone on here do it and was curious what year and model KTM subframe to get and what all modifications you need to make to it? Those little brass insert things are ripping out of my rear fender and would much rather just do away with all that and make sourcing plastic easier when I need a rear fender or side panels.

 

[snydes]

One of our members had a custom built subframe that uses a KTM rear fender and a modified seat pan that uses the back half of a KTM seat and the front half of the Alta seat. The seat pan for me it the biggest hiccup, building the subframe wouldn't be that hard. In case you hadn't already seen it, there are a few brass insert repair ideas in this thread;
Little brass thread inserts in plastic -- How to fix
Those darn inserts are in my mind the biggest annoyance of these bikes, which in the big picture isn't that bad, but annoying they most certainly are.

 

[C5tor]

I think that was @Ronny Showman that had the custom FMX setup for his Alta.

Electric FMX

 

[snydes]

The one I was thinking of was @Mat Rebeaud
Totally forgot about Ronny Showman’s bike.

 

[C5tor]

There's also our other resident FMX/stunt rider @Cyssko, from Cirque du Soleil.

Alta in Cirque du Soleil

 

[Fourth_Floor]

Subframe doesn't seem that bad to do. Any ideas as to how they're combining the two seat pans?

 

[snydes]

I do not. My best guess is they took the two halves and maybe used some form of a splice plate to overlap on the foam side.

 

[F451]

I do not. My best guess is they took the two halves and maybe used some form of a splice plate to overlap on the foam side.

That doesn't sound like it would be too hard to do, use some heavy duty 2 part epoxy.

And I thought I read somewhere here that someone used a KTM subframe and seat and that front of the KTM seat mounts matched up with the Alta mounts. Does anyone else recall that or am I imagining it?

 

[flintpunk]

I think if I break mine, I’ll fabricate one from aluminum or titanium and set it up to use a Yamaha seat, fender, and number plates.

 

[snydes]

That doesn't sound like it would be too hard to do, use some heavy duty 2 part epoxy.

And I thought I read somewhere here that someone used a KTM subframe and seat and that front of the KTM seat mounts matched up with the Alta mounts. Does anyone else recall that or am I imagining it?

Here’s the post;
MXR 2019 won't turn on

 

[Jmazz274]

Mat’s is a custom welded tube rear subframe (I think titanium), running 07 Honda 2stroke side boards and rear fender. Seat base from what I remember is fused/joined bases (Alta front, CR rear... Mat can correct me if I’m wrong)... his dad Antoine created it, he’s a real perfectionist when it comes to those finer details.

 

[Fourth_Floor]

Mat’s is a custom welded tube rear subframe (I think titanium), running 07 Honda 2stroke side boards and rear fender. Seat base from what I remember is fused/joined bases (Alta front, CR rear... Mat can correct me if I’m wrong)... his dad Antoine created it, he’s a real perfectionist when it comes to those finer details.

Thank you for the info!!