Does anyone know what the float setting is on the HO carb?

Thanks hondabuster I'm going to try to get it fixed today. It's hard for me to belive its lean because everytime I take the carb off it has gas puddled up inside the intake boot. [img]i/expressions/face-icon-small-confused.gif[/img]

 

The puddleing could be due to the lower velocity of air flow. I was thinking about the black plugs...are they old or the edges of the electrodes worn? The edges of the center electrode should be dead sharp, and not rounded. This motor may benifit from the platinum or iradiam plugs, because they tend to burn cleaner.
Are there any other symptoms of rich? smokey exhaust, loading up, starts up cold with out choke?

 

Spark plug link

This is a link for jetting by sparkplugs, it shows all the nice and not so nice conditions.

Yes you can get a 37.5 pilot jet

Is the needle and needle jet the originals to the 40mm carb, What have you changed from the original 40mm.

This is how I see it. You have put a carb that was tuned to run on a 499 cc motor on a 683cc motor that is 37% larger
This in stock form should make the 700 run lean, thats why when you increased you mainjet size it ran better. But the mainjet only has an affect on just over half throttle to full throttle. So you'll have to concentrate on the Pilot air screw & pilot jet which control idle to 1/4 throttle and the throttle valve(slide) 1/8 to half throttle.
Another thing that you may consider is the vacuum signal to the carb is different now, the diaphram and spring were tuned for the 500 and now the 700 is sucking on them. Every thing else being equal the 700 should produce more vacuum than the 500 which means the throttle slide and needle assembly are out of phase to the motor requirements, try a stiffer spring in the diaphram. The slide has a major effect on 1/8 to half throttle and there is a transision between the pilot and the slide starting at about at about 1/8 throttle.

Hope this helps, you may have already addressed these issues but this is where I would start.

Brambles

 

Your only feeding one cylinder at a time on the 700 vs the 500 so it's like two 340's instead of one 500 cylinder.

I also think a slide spring change may be needed but I can't direct you to the one you may need.

 

Thanks for all the replies I think I got it figured out. I have took the carb off about 6 or 7 times the 1st time I took it apart and cleaned it again and adjusted the float. It had just a little bit of water in the bowl & the float was to high so I adjusted it. Put back together and still did the same thing. I now have the clip on the needle on the 5th position down with the mixture screw almost 2 turns out. So it was lean & I still have just bearly a little studder so maybe I'll GETTER DONE today [img]i/expressions/face-icon-small-happy.gif[/img]