Hi I know this may be an old theam but there is a lot of confusing information out there. I have a 73 westy with a 1600 AD engine, believe stock dissy and a 34 pict 3 carb. Only had it a few months, already replaced points with ignitor and adjusted timing which was way out, runs a lot better but it won't smooth idle, so plan on stripping down carb, got new bushes and overhaul kit. Figures while I am at it might as well change the jets after all they are potentially 40 years old. Not sure of what the stock jets should be and have seen many threads on up rating the main jet to 130 can anybody recommend the best set up.
Check that you are running a stock oil cleaner with preheat. Also check you dont have any air leaks in the inlet manifold. Check if you can wiggle the throttle spindle in the carb . If you can it will be causing an air leak and problems. Clean the carb out thoroughly. Also make sure there arent any holes in the exhaust. Make sure all the tappets are adjusted. Also look at the spark plug colours for differences as that may point to leaks. Exhaust leaks can cause problems as the exhaust gas wont leave the cylinder properly so it runs lean. Check compression on all cylinders. Then start messing with changing carburettor jets...
Can't see the point in changing the jets personally. There's not a lot that can go wrong with them...
As above, check all the other stuff before fiddling with the carb. But...always worth giving your carb a good scrubbing, outside and in. There's nothing much that wears out, apart from possibly the throttle shaft bushes, but they can be replaced. Get a can of carb cleaner and an air duster aerosol, take the thing to pieces, remove all the jets and give all the passageways a good blow through. No real need to replace anything, apart from possibly the sealing o-rings. Putting a 130 main in to richen things up a bit is a good idea (you should have a 127 as stock). I put one in, but I fixed a lot of other stuff at the same time, so I'm not sure the improvement is down to the jet. Do it anyway - can't do any harm. Southern Carbs will sell you one.
Thanks for the info. Stock strainer fitted, did the oil change couple of months ago before going on holiday. Have replaced the intake manifold boots and fitted monza exhaust before I checked the timing, found out that the plugs fitted when we bought her were wrong, seems the heads were changed at some point probably when Devon engine fitted. Have checked spindle and think there is play in it, just as well I bought some new bushes. I will get a 130 jet before I strip it down. I just wasn't sure as to what the stock, main idle and air correction jets, were supposed to be. Not sure if anybody has tampered with it before we bought it. Fingers crossed when I have completed rebuild will run sweet. Next big trip is up to Lincoln before Christmas. If we can find a campsite that's open all year.
It's unlikely that anyone will have changed the jets in a stock Solex - there's no reason to, so you should be ok.
