Subframe question

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Subframe question

Post  SFXR on Wed Mar 11, 2009 5:54 pm

So I'm down to the subframe in my tear-down project. I notice that the only thing keeping up the back half of the bike is one bolt through the frame. Only my bolt doesn't have a nut on the end of it! Shouldn't it? Not much of the bolt is showing through to the other side, and the frame weld right there is bumpy enough to restrict a nut anyway. Maybe it is supposed to be like that, but it seems counter-intuitive and the shop manual does not say. thanks.

BTW, I usually have a pro-moto billet rack on the back. that seems to be about as sturdy a rack as you can put on--but I am still relying on two bolts in the end of the subframe. Those bolts don't go all the way through the subframe either, just into it. Looks like any subframe strengthening has to be done with custom metal brackets and such. Do the lower arms ever give way (bend, crack)? Or do the bolts usually give out first?
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my $.02

Post  Bump on Sat Mar 21, 2009 11:15 pm

Sorry, not sure what bolt you mean.

You might consider one of the rear fender braces from fourstrokeworks.biz.

If you load up that aluminum subframe for several thousand miles you might have it fail. Some say theirs have. But I think the pairing of the giantloopmoto bag and the fourstrokeowkrs.biz rear fender support is pretty good. I think the one I got frm them is stainless round, so it's pretty damn good quality.

SFXR wrote:So I'm down to the subframe in my tear-down project. I notice that the only thing keeping up the back half of the bike is one bolt through the frame. Only my bolt doesn't have a nut on the end of it! Shouldn't it? Not much of the bolt is showing through to the other side, and the frame weld right there is bumpy enough to restrict a nut anyway. Maybe it is supposed to be like that, but it seems counter-intuitive and the shop manual does not say. thanks.

BTW, I usually have a pro-moto billet rack on the back. that seems to be about as sturdy a rack as you can put on--but I am still relying on two bolts in the end of the subframe. Those bolts don't go all the way through the subframe either, just into it. Looks like any subframe strengthening has to be done with custom metal brackets and such. Do the lower arms ever give way (bend, crack)? Or do the bolts usually give out first?
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Re: Subframe question

Post  doug@dsa on Sun Mar 22, 2009 12:47 am

Try looking here for sub-frame stuff. http://www.advrider.com/forums/showthread.php?t=258211

I have the Dirt Bagz sub frame support. It helps with the fender flop. http://www.dbzproducts.com/extras.htm


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Re: Subframe question

Post  SFXR on Sun Mar 22, 2009 4:34 am

i guess I wasn't specific enough: i'm referring to the existing subframe, (ie, two aluminum rails starting from just above the footpegs that go out back to support the tail fender, then back to the frame at the top of the shock).

I have a long bolt that goes through the frame at the top of the shock. It goes thru the rail from the right side, thru the frame, and out thru the left rail, ending in ... nothing. Just 1/4" of the bolt sticks out on the left side. Looks like it ought to have a nut on it on the left side, but there are only a couple threads sticking out, and the weld there would keep a nut from tightening flush against the subframe rail. Someone with their seat off please take a look at yours and tell me what's there! THanks!
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can't help

Post  Bump on Sun Mar 22, 2009 5:07 am

my bike isn't here for a few weeks so I can't look at it. A picture is worth a 1000 words sometimes.
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no nut

Post  Mythic on Sun Mar 22, 2009 8:44 am

the sub-frame itself is threaded on the L rail for that bolt - no nut required, needed, or wanted.

(& just an FYI which I'm sure you discovered, there are 2 otherbolts on the anglular supports helping hold your subframe on naughty )

As for the PMB rack - most drill the holes all the way through the plugs in the sub, then tap for the next size larger bolt (8mm I think, but don't take my word for it). And yes, it is just kinda hanging out in space, that's why 25lbs (& hopefully less) is the suggested absolute max by any of the "bolt on" rack
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+1

Post  Bump on Sun Mar 22, 2009 6:32 pm

Yup, I hear a lot of that done even with the guys who aren't adding luggage.

Mythic wrote:the sub-frame itself is threaded on the L rail for that bolt - no nut required, needed, or wanted.

(& just an FYI which I'm sure you discovered, there are 2 otherbolts on the anglular supports helping hold your subframe on naughty )

As for the PMB rack - most drill the holes all the way through the plugs in the sub, then tap for the next size larger bolt (8mm I think, but don't take my word for it). And yes, it is just kinda hanging out in space, that's why 25lbs (& hopefully less) is the suggested absolute max by any of the "bolt on" rack
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Re: Subframe question

Post  SFXR on Mon Mar 23, 2009 4:37 pm

Mythic wrote:the sub-frame itself is threaded on the L rail for that bolt - no nut required, needed, or wanted.

thank you!
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Re: Subframe question

Post  Guest on Tue Mar 24, 2009 7:14 pm

At the very least you will need to drill and tap the sub frame to next larger size.
I sheared the two stock size bolts out the first time I used the rack.

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Re: Subframe question

Post  SFXR on Wed Mar 25, 2009 3:56 pm

Putting my bike back together, i can't seem to make the rear brake fluid reservoir mount up to the brass tab. Is that where it was? Grrr! Looks like there is no way it could fit up there when the subframe is in the way. Could someone please save me with a photo?
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did you check your swingarm for water inside?

Post  Bump on Wed Mar 25, 2009 4:32 pm

some guys drill a couple of weep holes at the end. might be a good idea because you'll surely eun through some water back east.
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