Shaw Derbi

todd amundson /

Had to take this apart because the trans side bearing had the crank spinning inside of it. Lots of travel up and down, side to side. Of course the crank is toast because it wore a nice hyper race surface in itself. I knew this was Shaw's Derbi which is on its third owner. Wanted to take a few shots of what he did.

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Daniel mentioned a crazy untunable cylinder recently that Shaw did. This is tunable I think but the intake window blows through the skirt a bit because it's giant. Has decomp hole drilled through it. Piston will hit decomp on start up and I think that crude divot was put in by the builder? I can't tell. Assembled without a gasket just yamabond. Lots of JB weld but only a little showing in the transfers. Crank had lube slot cut into small end. Aluminum base gasket with razor thin cereal box on either side. About 3 mm thick.

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Re: Shaw Derbi

todd amundson /

There's a hole in the center of the photo.

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Decomp added

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I do this but have not done it with double ear clips

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Re: Shaw Derbi

todd amundson /
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Not sure which order but:

Go Derbi, Jesus Saves, Shaw

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Re: Shaw Derbi

nice

Re: Shaw Derbi

Thanks for sharing! We have a Shaw 50/50 stock Puch cylinder that I have been meaning to do port-mapping and pictures for but have had no reason to pull the bike apart. One day. Bike is stupid fast with a 15SHA and bitturbo. It is nuts. And it has been running like that for 13? Years? Maybe more.

Re: Shaw Derbi

Wanna see that port map for sure

Re: Shaw Derbi

That intake is wild! Maybe I need to take another crack at that magnum jug...

Re: Shaw Derbi

RAD to see • Honest²

Re: Shaw Derbi

Kevin Bishop /

Is that a 1” pipe for an intake?

Re: Shaw Derbi

todd amundson /

no It’s metric so I’m pretty sure this is a 28mm header off something. The cool kicker is the decomp channel on the 47mm head is filled with maybe JB weld, then he ran the gases straight out the intake side of the jug rather than use the leaky trough out the exhaust.

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Re: Shaw Derbi

If the decomp hole is plugged with JB Weld , there shouldn't be any gasses going anywhere , other than normal 2T flow .

Maybe he tried re-routing decomp gasses to the intake prior to plugging the decomp ?

Re: Shaw Derbi

PD it still has a hole it just realease compression to the intake instead of going allllllll the way around the stupid ring in the head.

Re: Shaw Derbi

OK .

That's the second post I miss-read today . I better go back to bed . :(

Re: Shaw Derbi

That’s brilliant. The main reason why I took the euro kit off my derbi is because it was near impossible to start with out a decomp.

Re: Shaw Derbi

Starter shoes are the worst.

Pull start disc are the best

FUCK DECOMP

Re: Shaw Derbi

Id prefer to keep my pedals, but also a pull start would be cool?

Re: Shaw Derbi

Ed - Dead Possums /

Love to see his work. Being at Shaw's house I was a kid in a candy store! So much knowledge, and he loves to tell the stories of the good ol days.

Re: Shaw Derbi

Kevin Bishop /

> todd amundson Wrote:

> -------------------------------------------------------

> no It’s metric so I’m pretty sure this is a 28mm header off something.

> The cool kicker is the decomp channel on the 47mm head is filled with

> maybe JB weld, then he ran the gases straight out the intake side of the

> jug rather than use the leaky trough out the exhaust.

Damn not far off from 1” probably 26mm ID then. Sounds like a seat post cutoff. I love repurposed parts.

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