Exhaust valve

Bill Schmidt · Posted: Mon Oct 01, 2012 7:35 am Post subject: Exhaust valve

When I did a top end job on my 1991 kx125, I noticed that the power valves (exhaust valves) were missing,as were the linkages. It has bolts in the area where the linkages/shafts would go. RTV was used to seal the bolts from leaking. This does not have the blended power valve plugs like the fast CR125s have. My question is: am I losing compression ratio by not having plugs like the Hondas?
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Bill Schmidt

'95 Trackmagic 125 shifter (Kawi)
'88 Red Devil F500 4-link rear (Rotax)

Bill Schmidt · Posted: Tue Oct 02, 2012 3:24 pm Post subject:

With all the gearheads we have, nobody has an idea on this one?
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Bill Schmidt

'95 Trackmagic 125 shifter (Kawi)
'88 Red Devil F500 4-link rear (Rotax)

Spencer Uzri · Joined: 18 Apr 2006 Posts: 798

Possible. At or near TDC, the piston-cyl. should be a sealed volume region. However, there is probably extra volume created by the open space leading out to the exhaust, & that would affect the back pressure generated by the pipe expansion chamber's resonance. I'd bet that if you get some plugs & seal it up, you'd probably notice a difference.