By Glen Morgan
TUCKING THE CHAMBERS AROUND THE BACK WHEEL
If you have looked at the photos with this article and some of the photos in the galleries on Murrayís site, you will have an idea of the problem. I donít know how long your wheelbase is or how you want to route your pipes, so Iíve taken quite an extreme approach in the hope that it will cover most needs.
You will see from the photos that Iíve kept the header pipes in close. This means (see photos) that the chambers extend well back into the area occupied by the rear wheel. I have also installed a 4 inch shorter swinging arm which brings the chambers and the pipes further into competition for space. Added to this, the chambers themselves are over 4 inches in diameter, so itís starting to get reasonably crowded.
Iíve assumed that you are not going to chop out, raise and reweld the cross tube behind the gearbox ,and that you are going to stick with the standard rear footpeg mounts for your rearset pegs. Iíve made this assumption on the grounds that youíre keen to stop welding and go racing.
This also means that if you decide that you haven't got the time or the gear to tackle making chambers, you can order a pair with a reasonable expectation that they will bolt straight on. The further away from the standard frame you move, the harder it is to fit pipes from a distance. A lot of people who make pipes prefer to have the bike and do all of the fitting themselves. After all, there is some pride and reputation at stake!
Iíve taken a pattern off the T500 pipes Iíve made so that I can form them hydraulically. Hydraulic forming has the advantage that you can do "production runs". Once you have the basic form worked out, you can produce variations to cater for different performance requirements. If you are interested in giving it a go, look at Michael Mooreís Eurospares site on the net. He does a good job of explaining the basics, but keep in mind that making a convoluted two-stroke header and chamber can have a few wrinkles in it, both of the technical and physical kind.
** Iíve taken photos for this article so that they you can see which way the bends go. Take the left side: the header crosses over the left hand front downtube, then goes down under the engine where it joins the diffuser cone. Just before it joins the belly section, the cone has a bend which takes it upward and outward at about 45 degrees from under the cross tube behind the gearbox. The next bend is in the belly section and continues in the same direction, making room for the wheel. The final bend is downward and inward, to tuck the chamber under the footrest bracket and back in toward the wheel. The right side system is pretty much a mirror image of this.
I can think of at least one other way to do this, But however you do it, if you get the pipe nicely positioned under the footrest and well tucked in toward the wheel, the mounting bracket can go straight up to the footrest bracket. You need to think about this mounting business when you plan you pipe.
Original text and images copyright reserved: Glen Morgan 1999
HTML code, editing and image conversion by: M Barnard 1999
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