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SS180 reed valve tuning

Posted: Sat Jun 22, 2013 11:06 am
by Dryballs
I've been building a standard engine for my vespa lately and I realised that the carb I was missing was going to cost me a fortune

I started looking for other options... I've bought a grand sport px piston and I thought instead of welding up the window, I should look at reed valves

Here's where I'm at...

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Checking out how a px carb will fit etc

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I had a reed water cut to a shape I thought might work, then spent a few hours grinding it to make it fit!

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This is about what I've ended up with so far

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Test fit

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Carb box sits at the same height as if it was on a standard carb

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Starting to cut the barrel so the reed will fit in there... I've got a few plans for some porting and port timing but I might dyno it first with as few mods to the barrel as possible to see what it's like

Re: SS180 reed valve tuning

Posted: Sat Jun 22, 2013 11:24 am
by GLscoot
Your knowledge and skills are far better than mine. I fitted a SIP reed valve block & RD reeds, PHBH26mm carburettor, DR180 Barrel and SIP exhaust to my conversion and the thing flies. I could not believe what a difference it made, I will have to fit a fuel pump in the future as I can only use have a tank of fuel before it starts to splutter, but thats for the winter I am just enjoying pulling up at lights at the moment. I do still need to run her in so I am being careful.

Re: SS180 reed valve tuning

Posted: Mon Jun 24, 2013 9:04 pm
by PompeySpecial
very impressive work m8

Re: SS180 reed valve tuning

Posted: Wed Jun 26, 2013 5:00 pm
by cgt75b
Dryballs what was the carb that was on it it originally size etc ?

Re: SS180 reed valve tuning

Posted: Fri Jun 28, 2013 6:33 am
by Dryballs
It's 23/26 so effectively a 23mm carb

It's not so much the size of carb that I'm doing this, it's the fact that original carbs cost a fortune and are actually quite hard to set up well

Re: SS180 reed valve tuning

Posted: Fri Jun 28, 2013 9:47 am
by victor
GLscoot wrote:Your knowledge and skills are far better than mine. I fitted a SIP reed valve block & RD reeds, PHBH26mm carburettor, DR180 Barrel and SIP exhaust to my conversion and the thing flies. I could not believe what a difference it made, I will have to fit a fuel pump in the future as I can only use have a tank of fuel before it starts to splutter, but thats for the winter I am just enjoying pulling up at lights at the moment. I do still need to run her in so I am being careful.
Interesting - any more info about that conversion, photos, blog? Ciao V

Re: SS180 reed valve tuning

Posted: Thu Jul 25, 2013 10:10 am
by Dryballs
I got it running last night!

I ended up changing the gilera reed for a minarelli one

I also did a bit of porting to the barrel. Mainly to the exhaust and inlet, but a little bit to the transfers too

I still need to recess the head into the barrel to get my squish all good but I couldn't wait!

I also did a 12volt conversion on my stator using a bajaj stator

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I've also ditched my pk fork and disc for a standard fork with a bit of bling

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Re: SS180 reed valve tuning

Posted: Thu Jul 25, 2013 10:29 am
by Dryballs

Re: SS180 reed valve tuning

Posted: Sun Sep 22, 2013 12:26 pm
by Dryballs
Well it's pretty much finished...

My ignition crapped out so I got a scootrs one

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I've jacked the barrel up 3mm so I've recessed the head accordingly
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The final piece of the puzzle is to weld up the air box. I don't have a tig welder so did it budget styles with my mig welder. I'm happy enough with the result!

I've welded the bottom of a px air filter to an SS air box
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I'll do a bit more running in then get it on a dyno to see where it's at, but so far it runs really well

Re: SS180 reed valve tuning

Posted: Mon Sep 23, 2013 8:03 am
by ducksta
good work