So as some of you know, I've been thinking/planning on a new project bike. Haven't had near the time to work on it lately like I'd like to, but I've gotten this far.
The project is of course, the rolling insane asylum that will be my 500R drag bike motor in an 85 250R chassis setup for flat track racing. Yes, ladies and gentlemen, its already been well established I am nuts. Save the calls to the mental ward, even they have given up all hope for me.
Those familiar with the 500R conversions using the 250R frames know that there has to be mods to the bottom of the frame rails to make the engine cradle fit better. Theres obviously several different ways (all well debated, BTW) but the fact of the matter is you gotta work on it. Anymore, when I look at projects, or problems, I attempt to find the most effective way to use my time. Less time I have to use on other stupid *Edited**Edited**Edited**Edited* gives me more opportunities to focus on whatever I'm doing, its just more productivity for me. So... as the frame was sitting on my steel table, with the 500R motor looking in it, all I could imagine was having to pull the motor in and out of the frame a hundred different times, trying to turn the frame over and prop it up to cut out the frame rails, do any kind of welding, grinding etc being a total pain in the ass. So, I thought to myself, "I need a way where I can hold this thing pretty much full assembled, at a decent height, and have the ability to turn it or move it into whatever position I need at that moment..." And this is what I've come up with.
The 250R frame, if the sub frame is level the back bone is at a 25 degree angle, so it had to be mounted at that same angle for it to set fairly level. Mine is sagging slightly at the moment, but I'm pretty sure if I just run some weld beads up the backside of the square tubing it'll pull it back up some. You'd be surprised how good weld is for doing stuff like that, straightening (or warping) material back. The orange face plate is actually from an engine stand (you can see the remains of it under the table in a picture or two I think), and its got holes drilled all the way around it, I think theres 8. So the frame can be rotated, and locked, into 8 different positions. The face plate is held to the frame with 2 bushings that fit down into the steering neck (bearing races removed) with a large piece of all thread stock, and 2 pieces of angle iron holding it all together. It does, unfortunately, twist a little side to side when you go to hold the frame side ways, so I'm liable to add another support brace to a bolt mount on the frame or perhaps another piece of plate to act as a wedge so it can't twist any in the bushings. The whole outfit, even though it isn't even welded all that well right now (haha, my stick welding is near pathetic) its pretty sturdy. I was standing out on the end of the sub frame, it did flex a little bit but not a whole lot. I'm pretty confident you could have pretty much an entire 250R suspended in the air like this minus the front end and not have any problems once everything is hooked together all the way.
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Originally Posted by Billy Golightly
