Well I start out and tell you what I have. I have a 500HO carb on my 700. It runs great except at a dead stop and you nail the trottle it has a little hesitation and runs great after that. If you are rolling and nail the trottle the hesitation is not there. I let it idle for a while and pulled the plug it is black around the treads but on the electored it looks like a dark tan. It sounds like its running rich at idle because its loping just alittle. What sould I adjust? The air screw is 1 turn out, clip on the needle is on the 2nd positon down and the main jet is a 162.5. It runs great except at take off. Thanks

 

The mixture screw, if it's located between the throttle plate and the engine it's actually a fuel adjustment screw. At one turn out, you need to go smaller on the pilot jet to lean the pilot circuit. You might also try to stretch the slide spring to add tension on the slide, it may be opening to quickly.

It's seems logical that being this carb was set up for a single 500cc engine, that installing it on the 700 twin where your feeding two 340cc cylinders one at a time it would be rich. I don't have the magic answer, you'll just have to experiment. Maybe someone will chime in that's done this mod to help more. Good luck!!!

 

Howd you arrive at 1 turn out, on the mixture screw? Best idle?
any vacumn leaks?
Its possible, the bigger venturi, of the 500 carb, is always gonna have a flat spot. It has to do with the velocity, being much lower, but the volume may be the same. Play around with the mixture screw, going richer, may minimize the hesitation.

 

Thanks for the replies. Well I have had the carb off so many time I can't remember how many. It had a real bad Hesitation at almost half trottle and it turned out to be my clip on my neede was to low. I put it back on and it ran great except for alittle hesitaion at about 1/16 to 1/8 trottle. I tought it was also rich on the pilot that why I have it at 1 turns out. I have not tried to adjust it anymore because I was tired of taking the carb off and putting it on so many times. It's been a week or two so I'm ready to tinker with it again.

 

OK I'm still having problems I can give it throttle just bearly and its real rich. I gave it throttle where it was hesitating for about 20 seconds and pulled the plug and its black. The mixture screw is 1 turn out and the needle is on the top notch so I'm aussuming the pilot is to big. The pilot is a # 40 what size should I try? Do they make a 37.5 or do I need a 35? Thanks for the help.

 

If you pull off the air box cover, and take it for a ride, does it run better? This will lean things out, and if it runs better...then its too rich.
heres a good article on jetting, and it has symptoms of rich and lean, jetting

 

It doesn't do any better with the lid off. The plug is black so its running rich at the spot were it has a hesitation.

 

I got this off the honda site. later

Generally speaking, jetting can be quickly diagnosed by the following questions:
1) Low end performance
A) A lean condition is typified by surging and popping back thru the carb when steady light throttle is applied. It will cause popping during high rpm deceleration thru the exhaust (quicker when moderately lean, rapid when very lean, once every now and then when correct), once the rpm has dropped enough that the air speed thru the idle circuit is slow enough for it to pick fuel up that is. It can be quickly diagnosed by adding a slight application of the choke or starter enricher (if the popping stops, it’s lean). The intake will have a “droning” sound at steady throttle or under light acceleration loads in low gears when it is too lean. So, the question is; “Does it pop out the exhaust during deceleration with a closed throttle from high rpm to idle, while in 4th gear or above?”
A rich condition can also cause surging but will more than likely be very sluggish to respond to throttle inputs too. A quick diagnosis is to run the machine up to high rpm and listen for the occasional (once every now and then) pop out the exhaust, if no popping is heard, it is too rich on the idle circuit or fuel screw. If turning the fuel screw in does not remedy the richness, take a step down on the pilot jet and try again. So, the question is; “Does it pop out the exhaust during deceleration with a closed throttle from high rpm to idle, while in 4th gear or above?”
2) Midrange performance
A) A lean condition in the midrange is somewhat hard to diagnose. The biggest single giveaway is the sound of the engine. Usually when the engine is lean in the mid, it stutters and stammers and just doesn’t want to run right when it is VERY lean. When it is a little lean, it will cause the engine to labor slightly to run (it won’t sound happy), the engine will sound strained to maintain rpm, and the droning sound from above is easily heard thru the intake. It will also most certainly have a hesitation during sudden throttle application. This triggers a sound to be generated from the carb like the engine is sucking for air right before the engine starts to accelerate. A light popping will also be heard from the exhaust during steady throttle. When the jetting in the midrange is correct, you can accelerate thru the midrange with light throttle application or rapid throttle application and no hiccup or hesitation will be felt or heard. A method of diagnosis for a lean hesitator is to pull the choke on just for an instant and then stab the throttle the instant the choke is closed. If it takes off, the needle may be too lean or the pilot jet too small. Start with the needle, by lowering the clip one notch and feeling for the result. So, the question is; “Does the machine accelerate slowly through the midrange without any hesitation or hiccups?” Listen to what he says closely and go from there.
Rich conditions in the midrange are easy to diagnose. Under normal circumstances, a richly jetted midrange will make the machine very slow revving and unresponsive to small throttle position changes. If it’s the size of the pilot jet causing it, you will get no popping during deceleration no matter where the fuel screw is set. If it’s the needle causing it, you will be able to get it to pop during decel by adjusting the fuel screw. So, the questions to ask are: “Does it pop out the exhaust during deceleration with a closed throttle from high rpm to idle, while in 4th gear or above?” And “Does the engine react instantly with acceleration to small throttle changes when applying the throttle lightly?” (works best when in 2nd gear so the throttle changes can be felt immediately). If those 2 questions are answered with “No” and “No”, it’s most likely rich on the pilot circuit first, one step down on pilot jet size then repeat the test. If the answers change to “Yes” and “No”, lower the needle (raise the clip one position). Keep changing until you run out of clip positions. If it’s still needle rich, go to a leaner needle.
3) Top end performance
A) Lean condition on top is a little harder than the midrange. If it’s VERY lean, it just won’t take throttle. If it’s a little lean it will most likely rev quite good but, may SEEM to struggle to rev all the way out. Typically speaking, in a 4 stroke, it’s pretty hard to discern the differences from a little lean, just right, and a little rich. About the only way is to learn how to read spark plugs or find a lambda sensor to use. The question to ask is; “Will it take throttle past 1/2 throttle to ¾ throttle?” If the answer is “No”, it’s lean.
Rich conditions are fairly easy to discern. If it won’t accelerate or accelerates very slowly between ¾ throttle and WOT it’s rich. The question is obvious

 

Thanks for all the replies but I'm still lost in the dark. This thing starts and idles fine it runs better with the choke pulled out & pops back threw the carb if the throttle is stabbed with the choke off. That tells me that it is a lean condition right? But where the hesitation is (about 1/8 throttle ) it's rich because the plug is black. Any help would be greatly apperciated.

 

Youre right... both of those, symptoms say its lean. The poping and the running better with the choke on.
Its so hard to read plugs correctly, because now with all the additives in the gas, its not as easy as it used to be.
I jet strickly by symptoms, and your quads symptoms say lean. Id go at least 1 turn richer on the mixture screw, and more if the symptoms dont go away. If you get as far as 4 turns out from seated, then you need a bigger pilot jet.
Wheres the needle clip set at?
The hesitation at 1/8 should go away if you go richer on the mixture screw too.
Keep an eye on the plugs if you want...I doubt they will get any blacker, going richer on the idle circuit.