Cheap Hand Tools

Thanks for visiting our site!
Carb Mixture Screw
Checkout Ebay Auctions For The Cheapest Prices

Check out Amazon:

Account limit of 2000 requests per hour exceeded.

Here are some more information for Carb Mixture Screw:

When I first started racing Gas Powered RC cars, I used to struggle to get the engine into tune, while I was able to get the engine to start on a dime and it used to run fine for almost an entire fuel tank, it always seemed to over-heat near the end of the run. After many hours out on the track I can now finally say that I've got it down, tuning for me is now a 5 minute operation before I take my RC car out, and once it's dialed in I only need to adjust one needle a fraction of a turn to get it back to it's optimal settings.

I assume that your understand the basics of a RC Nitro Engine and how it works, if not please see my other articles which you can find on my website, see the resource box for details.

The Idle Screw

I always start with the idle screw, I adjust it so that the car will idle high when I'm first dialing in the engine. Once I get the engine up to temperature and with a tube that can keep it running without stalling I slowly adjust the idle down to the point where it's about to stall, then I turn it back about 1/4 to 1/2 turn depending on the temperature. If your car stalls often it can be worth while increasing the idle to prevent this, it's only a temporary fix while you sort out the other tuning issue, but it helps keep frustration levels down.

Low Speed Needle.

One of the great debates is which needle to adjust first, if your carburetor only has one needle adjustment screw then it's not a problem, but if like most glow engines you have two you need to decide which to tune first. I always start with the low speed needle, this is because when you adjust the low speed needle you change the high speed needle. Once the low speed needle is dialed in you shouldn't have to adjust it again. Make sure you keep it slightly on the rich side, when you RC Car idles the combustion chamber should start to fill up with fuel, this helps keep it cool. After a while the engine will stall, by measuring this you can tell if it should be richer or leaner. A good time is about 30 - 60 seconds before it stalls. The RC Car should pull off quickly from a standing start and should not bog down or flame out when you apply full throttle.

High Speed Needle.

Once you have your low speed adjustment needle dialed in it's time to start getting the power out of the RC engine. This is done with the high speed needle, which adjusts the air to fuel mixture of the engine while it as high RPM (about 40% and up). Keep an eye on the trail of smoke as this is your first clue about the tune. You want to have a lot of smoke coming out of the engine at all RPM, if at some point there is little or no smoke then you are running too lean.

Hints, Tips and Tricks

• Turn the needle clockwise to lean out and counter-clockwise to richen the mixture.
• A lot of smoke means you tune is rich.
• The sound can tell you about your tune.
• Reading your glow plug after a run will tell you a lot about your tune.
• Make sure to run your engine on the rich side, this will extend it's life.
• A lean engine will always put out more power, but it will shorten the life of your engine.
• Temperature, air pressure and humidity play if big part in the tune, different days will need different settings.

Gregory Alexander is an RC enthusiast, he spends most of his time racing and drifting RC Cars, more advanced guides and tutorials can he found on The Ultimate RC Drift Resource Site

How to Improve Your Motorcycle's Start and Warm Up, Idling and Acceleration

AIR CUT-OFF VALVE

The Air Cut-Off Valve is an extremely important part of the fuel / air intake system that is frequently missed even by competent mechanics, most of whom are not even aware of its existence or how it functions. Over time, air cutoff valves will harden up, perforate and/or disintegrate leaving your motorcycle in a permanently lean, low RPM range (0-2200).

Most early model Honda, Kawasaki, Suzuki and Yamaha motorcycles use air cut-off valves. Every Honda CB650, CB750, CB900 and GL1000 has one, located in the air intake tube between the air cleaner box and the manifold. The GL1100 has four, located in the top air intake passage of each carburetor, and every GL1200 has one located in the plenum box below the air cleaner box similar to the GL1000.

These valves are "air blockers", along with the carburetor o-rings, serving to restrict air flow, increasing the fuel-air mixture ratio when the carb slides are in the lower RPM range, up to closed so that the machine will start and idle smoothly with virtually no choking and accelerate rapidly, with no stumble or hesitation.

When typical starting requires heavy and prolonged choking to keep the bike running, when stalling and hesitation occurs even while "warmed up" and when backfiring pops while the throttle is shut off while cruising, most people will start fooling with the air screws to try to overcome the problem, only making it worse along with reducing their gas mileage.

Running with dysfunctional air cut-off valves can cause severe engine damage or failure. When the valves are dysfunctional, the engine pulls nearly total air into the low RPM range through the carbs and on to the combustion chamber. The fuel-air ratio is extremely poor with pre-ignition long before the normal 38 to 40 degree firing point, generating an enormous amount of heat, with no power, which is trapped a longer period of time in the cylinder before the exhaust valve opens.

This heat goes mostly up through the cylinder head, gradually incinerating the head gaskets and allowing engine coolant (antifreeze) to seep into the engine. You can easily spot when you are in trouble by a puff of bluish-white or white smoke on first starting the engine. Don't leave it alone. Change the head gaskets immediately or you could take out your bottom end bearings, ruining the engine.

For those of you installing new exhaust systems, you will discolor your head pipes, either blue (lean state) or gold (rich state) if the signs are ignored. You an destain your pipes using Blueway or Blue-Off but be careful not to rub the chrome, just dab gently. These destaining compounds are usually found at a Harley dealer or Harley-oriented aftermarket shop.

Honda genuine pipes, like many Yamaha pipes, have a double wall for a portion of the head pipe which masks discoloration - but also masks a bad state of tune. Even if your pipes are original and still in good shape, don't think you're safe if your motorcycle has any or all of the dysfunctional air cut-off valve running and performing characteristics.

If your 1975 to 1987 Gold Wing is not getting 50 to 58 miles per gallon (20-23 kilometers per liter), you have one of the most obvious signs of trouble. It is likely your air screws have been backed out to try to overcome the effects of the poor running, stumbling, starting, stalling and quitting.

INSTALLATION GUIDELINES

Refer to your Clymer, Haynes or Honda Workshop manual for location and installation procedures.

Replace your air cut-off valve/s then resynchronize all four carburetors to the #3 carburetor vacuum level using a mercury carb sync tool (carb stick) or vacuum gauge synchronizer tool. The number 3 carb is the constant fixed flow carburetor set at the factory.

DO NOT attempt to set by ear or just by guessing as the results can be anywhere from pathetic to disastrous.

DO NOT deviate from the book settings of your Honda, Clymer or Haynes manual. Wiser people than all of us designed this very effective and efficient intake and carburetion system.

To further insure against any additional vacuum loss, replace your inexpensive carburetor manifold o-rings. Vacuum loss can occur there and mimic the effect of a bad air cut-off valve. Paste a new set in with vaseline and make sure they are sealed with an ether check.

© Saber Cycle®

<input id="gwProxy" type="hidden" /><input id="jsProxy">

About the Author

Eugene Bileski represents over 46 years in the motorcycle trade as a past importer of Bridgestone, Ducati, Marusho, Norton and Yamaha motorcycles and is founder of Saber Cycle Honda Gold Wing Parts and Accessories at http://www.saber-cycle.com

Inexpensive air cutoff valves for Honda CB650, CB750, CB900, GL1000, GL1100 and GL1200 can be found on our website, in addition to the carburetor synchronizer tools and manuals referred to in this article.

<input id="gwProxy" type="hidden" /><input id="jsProxy">

How do I tune my Edelbrock 1406 Carb w/electric choke?

I have a Tach as well. I think I am supposed to start with them all the way down, then back them out 1 and a half turns. Crank the car, continue backing out until I hear it idle up and back it down a little (do this for both mixture screws). Is this right? Idle screw is already set.

well much more to tuning the carb than that.

That is the idle air mixture setting..
Best way to tune the idle air is with a vac gauge.. Hook vac gauge to full vac port, crank car and turn screws 1 at a time till you get the highest vac levels.

Next you need to check and adjust the float levels (most of them don't come set right out of the box) Take top of carb off, measure float height at rest and float drop. Needs to be 7/16" at rest and 15/16" to 1" drop measured at very front tip of floats..

Next is accel pump tuning.. The carb comes with pump linkage in middle hole.. I found the upper hole works best on most engines.

Then you have step up springs, rods and jets to change to dail carb in fully to your engine.

If you have a stock engine, then the jetting, rods, and springs will be pretty good out of the box.

If you have higher compression, or bigger cam, etc then you will need to change the step up springs for sure.. The pink 7" HG springs works best in most of those cases.

Thanks for visiting!