Cafe Racer Forum banner

crack addict

1563 Views 10 Replies 6 Participants Last post by  UngaWunga
I had taken the seat off my 350 to make some other work easier a little bit ago. Last night I found some cracks in the frame I had not seen before. The upper frame rails are cracked on both sides halfway between the shock mounts and frame rail loops. Each crack is about 1" long. There is also a couple of smaller cracks on the inside of the frame rails at the shock mount itself.
I'd like to think it was the byproduct of scary fast lap times but can only chalk it up to stress from being on the track. I've got to check for this stuff more often. It sure would have stunk to find out after something broke
1 - 4 of 11 Posts
I'll see if I can get a good picture

I've got no idea about the bikes past life but I bought the thing from Gary in VT and it was a inspected street bike at that point. It's almost like what you'd expect to see if it had an overloaded milk crate rack on it for a long time. That accessory wasn't on it when I got it though. It rides straight. This model does have the HRC bracing with the shock mounts braced with a tube running between them. Maybe it's too stiff there now and transferred the stess.
If I can get some photos to show the cracks well I'll send them to somebody who can post it here.
after spending some time cleaning up the areas it looks like the extra stiffening is probably the cause. Tyeing the shocks together moved the flexing stress upstream.
Pretty wild thinking about how much movement is going on there normally if putting a tube between the shock mounts can create that much extra stress. I took a couple of photos but it's tough to see. I'll email them to anybody if they want to take a look.

After the first season I was pulling this thing up the basement stairs and the small scrape over the edge of the bulkhead caused the water filled lower frame rail to start dripping. a poke with punch caused all the water to gush out. Talk about a sick feeling in the pit of your stomach. Welded up the rust hole and haven't seen any more problems there.
1 - 4 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.