

The needle is lifted upward (along with the slide) by the carburetor diaphragm as the air flow increases through the carburetor. The needle tapers down to a point that fits into the main jet. The carburetor needle controls mid-range performance. “Which Engine Oil Shall I Use?” – Engine Oil Explained in Very Simple Terms When you close the throttle on a downhill, if you hears popping or cracking sound from the exhaust, it is again due to the lean mixture. Even after repeated cranking, if the engine does not start, the mixture is lean. Another way to determine lean mixture is the difficulty you feel when cold starting. Put in LARGER main jets and take the bike out for another test run. You are running too LEAN a mix (less fuel than the optimum 1 part fuel to 14 parts air) for maximum engine performance. If before top speed the engine is running smooth, but has no power, seems to be running hot or knocking from the engine and you can’t push the bike to top speed, then your main jets are too SMALL. Low fuel efficiency and more smoke in the exhaust than usual are some of the characteristics of a rich mixture.ī. Another way to determine rich mixture is, when you cold start the vehicle and if the bike starts in the very first crank the mixture is rich (no need to use the choke in this instance).
#How to clean a k and n filter install
Install smaller main jets and take the bike for another test run. The mix is too rich (more fuel than the optimum 1 part fuel to 14 parts air) and you are getting an uneven burn and poor performance. If at top speed or before, the bike runs rough, heavy throttle feel or becomes hesitant and buck, your main jet is TOO BIG.

Again, do this only if you are experienced and comfortable running at top speed and you are not in danger of injuring yourself or someone else.Ī.
#How to clean a k and n filter full
Ride the bike full open and let the bike get to top speed. To make sure you have the right main jets, take your bike out to an open highway where you can safely (and legally) open the throttle all the way in top gear. High speed performance (80 KPH and up) is controlled by the main jets.

Please take the bike to an authorized mechanic and rectify the problem. In this case re-jetting is not the solution to the current problem. Note: If you do sense a loss of power, or rough running on a stock vehicle, it may be due to some other reason. So tuning will be different in different vehicles. So is the difference with other carburetors. Mikuni CV carburetor is different from the Keihin CV. Low and mid-range tuning is determined mainly by how the bike feels to you as you roll the throttle. High speed or top end main jet sizes are determined by full open throttle performance. We are now going to tune the carburetor without the help of a tachometer (engine speed). All tuning should be done on a fully warmed up engine because that’s the way you usually ride the spark plugs should have been previously checked and cleaned the gas tank should be at least half full a new or recently installed fuel filter if present the air intake filters checked for holes, and cleaned and all air intake and manifold connections tight and secure the battery fully charged and the carburetors synchronized, if it’s a multiple cylinder engine for optimum results. Since the main jet effects all speed ranges after idle, you need to get the main jets right first, and then tune the mid-range and low end.
