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Reply to "Chesil Speedster - my planned winter overhaul of '98 build"

A question for carb afficionados, if I may. If my main jets are 175, but I've no idea if they're right for the car or not (because it's not run right in my short ownership before taking it off the road to check ovef and refurb the car) , which service kit should I buy from Dellorto - the one with 150 main jets or the one with 170 main jets?

I know that's like asking 'how long is this piece of string I'm holding behind my back' but it's worth a shot! I presume in the absence of options, I'd go with the nearest (170) and see how it goes. Any advice appreciated. If none, I can always ask Dellort to perhaps swap out the jets in the service kit with 175s. Given how poorly the car has run due to so much dirt and crud in the system, I've no idea how well this car can run.  Just cleaning the entire system through should make a significant difference.

Thanks, Martin

Are the carbs just dirty on the outside?  If your carbs aren't leaking (gas or air) then you don't necessarily need to tear apart and rebuild.  What I suggest is observing how it runs on the idle circuits, buying idle jets and tuning appropriately before playing with mains.  This is because if (after getting the mains right) you start changing idle jets (gas or air), the mains will now not be right.  You need to get the idle circuit right first! I believe Danny has a good write up on carb tuning and I've always liked Aircooled.net's  https://www.aircooled.net/vw-carburetors-jetting-102/

The owner (John Connolly) has actually recommended driving Webers/Dellortos with the mainstacks pulled out in some situations for guys to understand how much you drive on the idle circuits and how important it is to get it right first.

Hope this helps.  Al

Last edited by ALB
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