Originally Posted by godwinmt
It may be easier/cheaper/lighter to split the HDPE up into 2 pieces say 7-8mm thick, and then bolt them to the outsides of the factory brackets. Adding in some standoffs throughout will help keep eveyrthing rigid/aligned, and the 2 smaller pieces should offer a bit more torsional rigidity than the single large piece.
Would you be better off for your adjustments at all by slotting the hole closest to the instruments on the mount in a circular manner? It might let you keep the relative positions the same while fine-tuning the viewing angles.
Definitely looks easy to produce with what's available though! I'm a huge fan of the ADVMonster LEDs.
I split last time I made one of these to be honest it really frustrated me. It just adds something else to work with eg. every time I'd want to drill a hole or something it would involve both pieces in most cases. I also think one piece would have just as much rigidity. Having said that the 10mm Delrin I have used before was well stiff enough I thought, so a 30mm piece would be in reality I think an overkill. Its just the existing frame mount is 28.5mm from what I can gather so 30mm is a nice round figure. Quite often here I OZ I have found 10mm steps with metal or equiv stock is quite common.
The instrument mounts actually have holes drilled at the non-istrument end that are the same distance from the other so I can change the angle of the mounts (make the angle greater or narrower) and also adjust the angle of the roadbook or instrument seperately. In the drawing I haven't yet included the adjuster (rod ends, both LHD/RHD) to fine tune and give extra rigidity.
My thought also involves a crash, or specifically the rider getting thrown foward. I think it was mention some posts back about using plastic shear bolts. My thoughts with the HDPE instrument mounts is that with a shear bolt included the mount would rotate foward in the event of such a crash. This point was made by someone in regards to Jonahs setup at the 2012 dakar. It was pointed out it was lower than others of which some thought had been put into a accident. Please don't take this comment as gospel as I think I read it somewhere here. Since there are a few designs coming through that are making use of polymers etc then thoughts in regards to stiffness etc are being discussed more.
2011 I think (correct me if wrong)
The other thing witrh HPDE it is pretty easy to build in some kind of shear section. I'm not going to try and figure this one out as I don't have the knowledge or programs to be able to run the math but I think its a lot easier than alloy.
In the end HDPE is easy to use in my shed and alloy isn't. I'd love to have access to some machinery that could pump out parts but even for the people that have it I'd assume they have other jobs to do so its something that gets done when the can. (still looking for that big pot of money)
Since you mention the monster LED's do you think they could replace a standard headlamp? Not a dirt bike lamp but something like found on a DL or 990 or something? I have a older model of the LED's and I was think of getting one of the 60's for the high beam.