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Idle Speed
Tech, carb synching is on page 50-51 in my Clymer book.
So far as the rising and falling at idle; I call this "hunting". The engine idle MIXTURE is not correct or similar on all four carburetors. As the mixture is not quite uniform the engine is hunting around trying to find a comfortable idle speed with the fuel mixture it is being provided with. Most accurate tool to set this is a "Color Tune guage". I don't own one. Was lucky enough to have access to one at PNW Rally last year. Several of us took advantage of it at that time. I know that afterwords my bike ran the smoothest it ever had. I have not gone near my carbs ever since. So afraid that I will loose the smoothness of that little synching and mixture adjustment that I do not want to mess with it. That was 12,000 kms ago and it still just purrs. I believe that the tool belonged to Denny Zander in Olympia Wash. At the same rally Steve Linderman had a bank of 4 vacuum guages that we used to synchronize our banks of carbs. All who took the time at that meet had big grins on our faces after we test road our bikes.
So far as setting the idle mixture without vacuum guages if you have access to an accurate shop tachometer borrow it.
Warm up the engine to full operating temperature. Remove the fuel tank and turn it around from its normal position and set it down where the seat would normally be. If necessary temporarily install longer fuel lines to connect the petcocks to the carbs. Hook up the tach and restart the engine with the petcocks on Prime. Plug off the vacuum hoses that would normally go to the petcocks. (golf tees work well). Now, noting your present idle speed slowly turn the idle mixture screw on #1 carb in slowly until engine speed starts to fall off. Now turn the same screw out slowly, idle speed should pick up again as you continue to turn engine speed will again start to fall off. Split the difference on the idle mixture screw at the highest tach reading. Go on to #2 carb and repeat your way across the bank of carbs. When finished the "hunting" sensation should be gone. If not turn each idle mixture screw in about 1/8th of a turn and try again.
After you have the idle mixture set properly then synch the carbs. You may have to do each of these adjustments a couple of times because they both affect each other.
Hang in there and don't burn your fingers.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"
Tech, carb synching is on page 50-51 in my Clymer book.
So far as the rising and falling at idle; I call this "hunting". The engine idle MIXTURE is not correct or similar on all four carburetors. As the mixture is not quite uniform the engine is hunting around trying to find a comfortable idle speed with the fuel mixture it is being provided with. Most accurate tool to set this is a "Color Tune guage". I don't own one. Was lucky enough to have access to one at PNW Rally last year. Several of us took advantage of it at that time. I know that afterwords my bike ran the smoothest it ever had. I have not gone near my carbs ever since. So afraid that I will loose the smoothness of that little synching and mixture adjustment that I do not want to mess with it. That was 12,000 kms ago and it still just purrs. I believe that the tool belonged to Denny Zander in Olympia Wash. At the same rally Steve Linderman had a bank of 4 vacuum guages that we used to synchronize our banks of carbs. All who took the time at that meet had big grins on our faces after we test road our bikes.
So far as setting the idle mixture without vacuum guages if you have access to an accurate shop tachometer borrow it.
Warm up the engine to full operating temperature. Remove the fuel tank and turn it around from its normal position and set it down where the seat would normally be. If necessary temporarily install longer fuel lines to connect the petcocks to the carbs. Hook up the tach and restart the engine with the petcocks on Prime. Plug off the vacuum hoses that would normally go to the petcocks. (golf tees work well). Now, noting your present idle speed slowly turn the idle mixture screw on #1 carb in slowly until engine speed starts to fall off. Now turn the same screw out slowly, idle speed should pick up again as you continue to turn engine speed will again start to fall off. Split the difference on the idle mixture screw at the highest tach reading. Go on to #2 carb and repeat your way across the bank of carbs. When finished the "hunting" sensation should be gone. If not turn each idle mixture screw in about 1/8th of a turn and try again.
After you have the idle mixture set properly then synch the carbs. You may have to do each of these adjustments a couple of times because they both affect each other.
Hang in there and don't burn your fingers.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"
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