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Home of  my Yamaha RD400  Drag racer.

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Ora et Labora

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Now the Transfers.we didn't do anything to the transfers on this set of barrels as we don't yet have the correct porting tools. But here are some molds we took so you can see what the RD400 transfers look like.

You can see how there are some quite bad miss matches and steps that can be cleaned up.
When we have the correct tooling we will raise the transfer ports from 51mm from TDC to 48.8mm from TDC.
This will give us 132 degrees of transfer duration. The RD400 has 113 degrees as standard.
The new blowdown would be 34 degrees.
Here is a bit of a port map for what we think will make a good drag motor
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Now for the Inlet.
We used  some RZ350 reed blocks that were modified by cutting out the center rib and using single TDR reeds. You then have to open up the inlet tunnel so that the new reed blocks fit. The hole spacing is the same as the standard RD spacing.
Here is a another bad pic of the modified RZ reeds. Also we have put a 6mm thick reed block spacer on the reed block
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The E crank weights 5.05kg as standard. If you do this mod you must be aware that you will increase the crankcase volume by 50cc