All

That depends on the alloy, so you cannot say that is the same for all frames. I believe (source: AJ from SH on this forum) that the different castings and extrusions are made from different alloys. Bottom line if you have to weld critical components (this is the case for all materials): 1. determine the alloys 2. determine the state...

That is an unwise thing to do. You have a good insurance I hope because you risk fracture occuring in the heat affected zones from the weld. Have you done material and FEM analysis and to examine the stress occuring in that area? If you read literature on aluminum precipitation hardening, annealing and aging you will notice that in order...

Based on what experience and knowlegde? it depends on the aluminum alloy used. Almost all high strength aluminum alloys require annealing after welding. This includes pretty much all motocross frames.

Awesome job on these articles! I really appreciate the work you put in making these articles and digitally conserving pieces of motocross history. The technical details which you describe and HQ photos make it for me worth reading.

I think you mean CRM Compositi

Awesome job Marvin, congratulations to Marvin and Mathilde! A very touching picture:

If you scrub with a scotch brite pad, use WD40 as a lubricant. It works wonders!

100cc disadvantage? I believe these guys will disagree

Source: AJ from Service Honda. He typed on this forum that Honda uses an alloy comparable to 7075 on (I believe) extrusions. This is not based on my own experience. If incorrect, my apologies.

Thanks for the remark Harescrambled! I didn't know that. Then it would be no problem for steel. For aluminum it is however dangerous if the heat treatment of the alloy is critical.

Some info about 25CrMo4 which your KTM is made of: http://www.saarstahl.com/fileadmin/saarstahl_extranet/images/04_produkt… I would suggest not to go above 400 degrees Celcius for more than 0.5 hours.

Aluminum frames are heat treated. If you heat an aluminum frame to a temperature at around 200 to 300 degrees Celcius the effects of heat treatment will be reduced (the material recovers to its original, soft, stress free state) depending on the alloy. Generally 6065 and 7075 aluminum is used. Therefore strength is reduced and material is softened comprimising the...

A 2012 KTM 250SX two-strokes costs $6695 and the 2012 KTM 450SXF four-stroke costs $8795. That $2100 price difference could finance your whole racing season.

This. How many top-ends can you do for $2100? A new piston every 25 hours using good fuel (we use 98 octane, 1:40), $150 per rebuild? Thats 14 top-ends for 350 hours of riding...

Thank you for publishing these articles! They are of awesome quality I think, also from an engineering standpoint Please keep up the good work, I always look forward to new articles

That vid just brought a smile to my face. Awesome, I love it! The bike looks awesome to but I can't help wondering how a Akrapovic or Scalvini silencer would look on that bike

I would be very careful from who you take advice from. What I would suggest is contact Honda and ask them for advice. Maybe contact Service Honda.

My guess is that the frames are pretty solid, designed for an average rider. Propably goes through a history cycle of loading. I have no idea about the FEA numbers, Pursang (www.pursangmotors.blogspot.com) have made their own aluminium frame. I would love to have their information and reference numbers for frame design.

A thread can never have enough semi-dressed women.

The frame you personally would prefer depens on a lot of factors. One cannot say it for you. It depens on your weight, length, riding style, conditions, power, torque, center of gravity and the list goes on. There is only compromise.