How do you set motorcycle carburators so the bike doesn't over heat from incorrect settings?

Answer 1

If you have multiple carburators, you will need to sync them first (ensure they are flowing the same amount of air). Next put a tach on the bike (assuming it doesn't have one). Richen the fuel mixture on one carb until the bike stutters, then start to lean it out until the RPM goes up and just starts back down (this will be lean). Turn the scre 1/8 turn towards the rich side, then repeat on the other carb. Then re-sync. This will set your idle.

For the High speed jet, take a ride, at 50 or so snap the throttle (just shy of the wheelie position), if it stumbles and doesn't blurb out black smoke, you are lean. At 80 or so, let the throttle snap to idle. If the motorcycle continues to pull for a split second after the throttle goes back, you are running rich.

Slow speed jets and needles don't require any adjustments unless you modify the exhaust or intake.

The best way to really tune your carb is to run it on a dyno with an exhaust sniffer to ensure good burn throughout the RPM range. Usually a shope will charge you $200-$300 depending on how much work they have to do to the carbs.

Answer 2

Setting them right is important, and must be done, regardless of what you're trying to avoid. It's unlikely to overheat an engine just from bad carb settings -- it's usually a combination of timing, valve adjustment, and fuel. Running a too-lean mixture will indeed increase temperatures, but it also reduces power, so you should notice it. Don't ride a bike with a known fault, and you'll be OK. Besides, they rarely go lean all by themselves -- if they do (gunk in the fuel line, etc.), you really will notice it, and you shouldn't be so stupid as to continue, no matter how important the trip. Stop, fix the problem, then continue.

Answer 3

It sounds like the jetting is too lean. If you raise the needles in the slides by placing a 0.010 inch washer under each needle in the slide, this will richen the mixture slightly at low and mid range throttle settings. If you have recently installed a oil in cloth type air filter, then you need to check that you have changed jets in accordance with the installation instructions, and maybe you need a bigger set of jets installed. Good luck.

Answer 4

It would melt a piston from a lean condition before it would overheat, i would think. But adjust the carbs to the highest possible idle on each, then screw mixture in until just perceptibly idles down on each.

Answer 5

The key to jetting the carbs is reading the spark plugs. If you have ever watched the pits at NASCAR you have seen the mechanic checking the plugs with a magnifying glass. Really simple: if the spark plug tip is black and sooty-it's too rich; if the porcelaine is white as far deep as you can see-too lean.
The spark plug is your window to the combustion chamber; it is the mechanic's crystal ball.

Answer 6

Don't lean it out too much. If you get pinging on acceleration you are too lean. If you like the power you get at a particular carb setting but are getting pinging, try higher octane fuel, or richen it up a bit.

Answer 7

Its called bike shop.Let them check the carbs,timeing.spark plug heat range and a few other things.This way your bike will run great and not harm the engine.