Tuesday, November 23, 2010
I received a call today from another BH tinkerer. His first words were, "Yer gonna kill yerself with those mounts." It seems that my assumption about the mounts and their intended function was all wrong. They are not there to keep the engine from moving up, down or around. They are to keep the frame downtubes from bowing out towards the front of the bike. It makes sense to me. So, I grabbed the ol' die grinder and off they came. He sent pictures to me some time ago of his mounts. They are nice, but he has different heads than I do and he doesn't have the same bolt holes as mine. Still, I should be able to come up with a similar setup. Time for some more head scratchin'
OK, boys and girls. I laid awake for almost 10 minutes last night and came up with, what I consider to be, a solution to the various issues that have been raised by experienced bikers, fraidy cats and naysayers (BTW, stop saying nay). There will be no welding on the frame and the mounts will be rigid enough to stop any, potential, movement in any direction. I have finished the right side. I cut a piece of 1/2 plate and drilled it to match the holes in my head (no, not that one, smartass). Using the original BH mounts, I drilled and tapped two more holes in the plate to match up with the holes in the mounts. The left side will be, somewhat similar, only with a much thinner plate bolted to the head because of the cylinder offset.
Later that afternoon.
Finished the left side. Since it is too thin to tap threads into, I welded a short, threaded bung onto the plate for the outer bolt. The other bolt goes through the plate and into the head. The BH mount lined up almost perfectly with the hole in the head. I just had to ream it a bit for wiggle room. All of the exposed bolts will get proper spacers to insure that the mounts all suck up tight to the heads.
Friday, November 19, 2010
While I'm tearing things down to the bone, I am trying to address every, little weak point that these bikes have. One has been, for many, the top mounts. Some have reported manifold leaks due to the original mounts being bolted to the intake manifold. I have noticed that I need to tighten mine fairly often. They now reside in the used parts bucket. Whenever I go to my favorite metal supply, I grab a hand full of mounting tabs (I used them for my tank mounts)and triangular gussets. They always seem to come in handy for various projects. With just a tiny bit of trimming and one hole each the gussets were perfectly sized to make these new mounts. The left side bolts flat to the head and the right side uses a spacer because of the offset cylinder head. Clean and simple. I was, initially, going to use just one mount on the left side. The two banks of the engine cannot move independently of one another, so one would probably do. I just couldn't stand the asymmetry. Additionally, this will quiet the naysayers who will warn of catastrophic failure, such as, "The bike will rip itself in half the first time you get on it hard."
I will need to redo the radiator mounts since they went away with the factory motor mounts. I imagine a couple of the aforementioned tabs will do nicely.