Engine Tuning Pt IV (Exhausting)
This bit I am intending to do. On my barrels the KIPS
valves don't line up well with the holes leading through to the exhaust port.
This seems to be simply due to slight misalignment in castings not a deliberate
step in the design (This misalignment varies between barrels - and between
sides on an individual barrel). Assemble the barrels and head and set the KIPS
valves to the optimum angle. Dress the barrel so that there are no abrupt steps
between the barrel and the valve. When assembling the valves make sure that
they stop in the correct position otherwise all your hardwork will be wasted.
On the exhaust port side I had a notch in the webs (Green circle). On the scrap barrels that I practice on, the web had cracked between the exhaust port and KIPS port - the crack having started at this notch. The result is a distorted barrel and siezed piston. To stop this happening on my good barrels I have carefully smoothed out the notch to remove the potential stress point.
Everybody I have talked to says that the standard expansions are difficult to beat. I have got a set of Huxleys that I want to try and will post the results when I get the bike back and running (these weigh a fraction of the standard pipes). From what I can tell it is a case of suck it and see as far as exhausts are concerned. The stock pipes have been modded by some to save weight nethod 1 is to remove the outer skin from a set of standard pipes, Method 2 is to take the inner expansion out and run using the outer skin. to save weight. Not sure how effective either is as I have never tested either.
On the dyno page are results for Nikkon, Huxley, Stock and Gibson pipes. In all tests Stock came out top but that is not to say another pipe wouldn't work better for a particular engine tune.
I have been using the MOTA 6 package to analyse changes to the KR and we think we have an expansion chamber design that may surpass stock. Will post dimensions soon and results if and when we ever build it.
Return to KR-1S Tuning Index Return to Main Index
This document maintained by
mark@teamsparrow.fsnet.co.uk.
Material Copyright © 2003 Mark Jordan