Posts
707
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4/4/2017
Location
IN
US
Fantasy
524th
Edited Date/Time
3/6/2018 3:14pm
My friend and I were riding singletrack the other day. He lost his balance in a rut and whiskey throttled into a large tree. The damage is on the motor cradle. Is there anywhere he can send the frame to and get it repaired. A new frame is a ton of money. The bike is a 17 crf250r with less than an hour of ride time. Any help is appreciated.
The Shop
Personally id just replace the frame. Idk if i could sell the bike with that kind of work done to it.
That's a bummer for your buddy. I'd rather be safe than sorry and just replace the frame. Scrap the old one or sell it to someone looking to do an AF conversion. They will have to cut that section out anyways.
If it makes your friend feel any better, I once wrote off a BMW M3 that because of my age at the time, I was only covered by Third Party Fire and Theft Insurance - it's a type of insurance you get in England where if you bump the car, it's on you but everything else is covered. I smashed it up bad and tweaked the chassis. By the time I had sold all the salvageable bits, I was 14k (in GBP) out of pocket. It still makes me sick thinking about the wasted money, but I console myself by remembering that it was just a piece of metal which can be easily replaced. Human life can't.
https://www.ebay.com/itm/15-Honda-CRF250R-Main-Frame-BOS/162914520133?f…
The alloy used in that section of the frame is most likely a 6061 alloy with a T6 hardness, or something very similar. A T6 hardness in 6061 has a 35,000 psi yield. Now if somehow you could find a replacement tube and find a shop to weld it in, the area of the welds would be reduced to basically a T0 hardness which has a Yield of 8000 psi. So in the concentrated area of the weld the integrity of the aluminum is drastically reduced and would very likely create a problem area down the road........
Hope that all made some sort of sense...
Pit Row
Got it.
It's still crazy to me how low speed and minimal the crash seemed. I was behind him and I heard the smack but thought it was the plastic skid plate cracking. Would have never in my wildest dreams thought the frame cradle would look like this. Crap happens I guess. His best bet it seems is to buy a new one and chalk it up to damn that sucks.
if you use the right material and weld it with the right rod the a secure job would more than last the life of the bike!
The key is the material, if you use 7005 or 7020 and weld with 5356 rods then the weld HAZ (Heat affected zone) will naturally age harden to within 10% of the origional strength, if you machined the ends to fit insid the it would be even better.
after 3 weeks it would have age hardened enough to use and it will continue to gain strength every day up to 6 months.
I am sure most problems that ocure with Aluminium frames is using wrong filler wire and also not allowing age hardening to take place, especially with subframe repairs.
In that area where the frame is dented it is not so much the structual part as it is braced by the engine (check many road bike that se the engine as part of the frame ).
having said that, unless you were friendly with someone who had the facilities and time it probably would be cheaper to get a used frame maybe frome a team who would have this type of stuff if you wrote to them nicely, we alway try to help out here.
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