Reed valve

Wesman07

Famous Member
Supporter 2020
Firepower:

I don’t think I’m following you on the intake over exhaust fix. Can you explain?

Your reed cage looks massive for the carburetor and engine size. Do I see a volume stuffer?

As far as my challenges, it’s starts with a size constraint. The size constraint makes total flow a challenge, forcing an exploration of lower tension reeds. This lower tension will only be able to perform well under the lower rpm range due to the lower frequency response, throwing the 360 degree intake timing option out the window.

For those that don’t know… the lighter the spring, the less force it takes to move but also the slower the oscillation. This holds true for all springs.

I have purchased .25mm carbon fiber to test against the .40mm resin reeds on the KX 85-100cc reed cage. I hope to have a little more to show next week.
 
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Firepower354

Well-known member
Firepower:

I don’t think I’m following you on the intake over exhaust fix. Can you explain?

Your reed cage looks massive for the carburetor and engine size. Do I see a volume stuffer?
I was referring to the early 4 strokes with an exhaust cam operating a side-valve setup, and the intake being a lightly sprung suction-to-open setup. Reductio ad absurdum or sumn'

Reed cage is from a 485cc Yamaha twin, so my 250cc single, albeit with slightly less aggressive porting, should be fine.
The 32.5mm venturi Tilly HR is a little small, but i have 38-40mm HD versions as well. No stuffer for now. I have more aggressive piston-port aluminum cylinders from Polaris ATV and sleds, all the same Fuji lineage. This is an interim step before milling the inlet side off an ATV jug and welding the whole Yamaha reed box in place, adding rear booster and tunnels to the transfers. Moving, and the force behind it, have slowed most of my projects to the moss-gathering stage.

John aged-out and stopped making his, but some interesting finds, IMO
I'd think that even fairly short adapter/spacer would allow a larger cage to fit.
 
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