i built a 03 450 for my cousin all was good till he was chasing me down a whooped hill and buried it into a washout when we were cleaning it we found some cracks i preped them out to get riding for the weekend a few months back and now im nearly done fabbing a sheet y out of 4mm ali i forgot the photos of the bike before we cut it up but have some of the y
all the shs went in free there was no tension on any piece and the engine pretty much fell itto place.
my thoughts are 1 i over stretched the shs and 2 the engine mounts were the 450 bolt on units as per the owners wishes i would have milled my own
it also has cr style head stays and when it was disassembled all bolts were tight as a nuns
Last edited by gregrobo on June 18th, 2011, 3:30 am, edited 1 time in total.
The front overlap is a good detail - it helps in not localising the forces / stress across the tube / plate. I would have had the outer plates come down to near that overlap, with a curved / diagonal weld (or, perhaps better, no weld) back up to the non overlapped section.
A major and common problem I see in people builds is welding across the side of the tube - as in, like your 'barrel' front mounts. It promotes a crack / failure, just like in your pic. It's a Real stress raiser in a non heat treated joint. Or even a heat treated joint. - it's called welding across the neutral axis (and the worst type, on the inside of a bent tube), not with it, which is infinitely preferable.
Either a plate mount, welded along only the edges of the tube / sheet Y, or if you have the room, a right angle section, once again, welded only along the edges of the tube / sheet Y.But , with the outer edge shorter than the inner length, so as to avoid a 'straight across' stress raiser. Good, inner corner radiused right angle 6061 T6 is easily available here in OZ. All welds should have good stop / start ends - no cratering. You might also have the room for 2 mounts either side, to take a bolt in plate for the engine mounting. I did this with a couple of Gen 5s, with some very experienced / thinking riders, and both preferred the handling to the first, welded in, single mount on one of them. But each ended up using a different thickness 'bolt in' plates. For drongos who might say it would make no difference, see the changes made on many bikes each year, to different thickness and materials, plates. And the varied mount plates offered to factory riders.
Plate Ys are fun to do, give you a huge variety of build options, and, in my opinion, infinitely preferable to machined from solid Ys, let alone tube inserts.
Looks good but I am not crazy about your bolt selection though, at least from what I see on the headstay- if that is threads all the way through on you are asking for trouble.
Using bolts with a shoulder wide enough to fill the hole (not sure the technical term) is critical to avoid cracking.
nmdesertrider wrote:Looks good but I am not crazy about your bolt selection though, at least from what I see on the headstay- if that is threads all the way through on you are asking for trouble.
Using bolts with a shoulder wide enough to fill the hole (not sure the technical term) is critical to avoid cracking.
What bolts did you use on the lower mounts?
thats the trouble with doing a conversion for someone else you only get half the parts the bolts were only used for mock up because he forgot to bring the originals
Last edited by gregrobo on August 24th, 2011, 5:32 am, edited 1 time in total.
Good to know- i also goop my bolts with enough 'right stuff' that you have to hammer them out when you disassemble the bike.
I think it makes a difference.
