> I believe it's because US-spec 1500s, among other lamenesses, have
> only single valve springs instead of the doubled springs used in
> Eurospec Spitters. I suspect that at these revs I'm hitting the
> harmonic values of these springs and causing them to buzz.
> Acceleration gets very weak in this range, but straightens out above
> 4500, coincident with the point where the buzzing stops.
The Eurospec dual springs cure a float/resonance problem somewhere
around 4200-4300 rpm. If you want to retro the dual springs you'll
also need the spring seats which go with them. TriumphTune UK has all
of this stuff. Nobody I called on this side of the pond did.
When I pulled the head on my 1500, I found that the single springs tested
at 30 lb versus the 123(?) lb spec. I think the inner spring is 40 lb.
Gonna be nice to have valves which track the cam lobes.
timd@hitu.enet.dec.com (Tim Dziechowski - '79 Midget 1500)
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