Posts
14
Joined
5/1/2014
Location
Gastonia, NC
US
Edited Date/Time
6/10/2021 8:22am
Has anyone seen a Honda crack in this area before? This is a 2004 CR125 with a total of 15 hours on it.
The Shop
Yes, loose steering head bearings can cause problems, that fork is a massive lever. But, on nearly every aluminium frame repair I've made at the steering head (and other areas of frames) , it's been down to casting lines and the stress raisers they focus (combined with the normal, serious forces a frame has to deal with), and other types of stress raisers that are often part of the design / casting. Any sharp edges / corners, say at the bearing landings, are massive stress raisers, waiting for a crack to be generated at.
Most of these frames are made of very specifically age hardening alloys (so as not to require post fab heat treatment) - well, most aluminium alloys are just that (within a wide range , not to mention 'work' hardening so many materials are prone to) and, hardness, tends towards brittleness when it's a result of 'working' the finished structure through usage. Most MC aluminium frames a quite overbuilt, to withstand usage / provide a big safety factor, so, many repairs can be possible, if not entirely advisable . It's when you get to real minimalist engineering, highlighted with Bicycles that it gets very risky to repair damage. I refuse most aluminium Bicycle repairs, and encourage owners to thank the frame for not failing catastrophically, and that they hang it up as part of their past, or completely scrap it, so others don't get tempted to re-use them.
When you replace a frame, with one of the same vintage ( unless it's brand spanking new), you generally don't know it's usage history, and, it's a bloody old frame in and of itself. So, be very wary of any old frame you get to replace another, or, indeed, any old AF frame you get for the usual 'AF" project. A 2007 model bike, generally has a frame that's had, right now , at least 10 years of 'age' to it.
This winter, after reading this thread, I inspected mine and I noticed this little guy. Only visible from the top, not from inside the tube or outside.
I wasn't alarmed and I also didn't know for how long it's been there. So I reassembled the bike and rode it keeping that in mind also telling myself I'll keep an eye on it.
Took a look at it this morning. Did about 5 hours of track time since this winter.
It grew considerably. Probably about 3cm long and visible from inside and out.
I don't know what I'll do with that thing for now... Not riding it anymore that's for sure. I'm pretty sad.
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