Some engines will actually have two size jets that may fall within the 1-3 spec in which case see which feels better when riding, generally the richer one.Īt wide open throttle only the main jet is working so these are also very easy to tune with a few jets and a bit of spare time. Remember if you don’t wait 10 seconds for the engine to catch up every half turn at a very slow idle this tuning process will not work. Nothing else other than the pilot jet has an effect at idle. If the jet is wrong, either having no stumble in one direction or the centre point being out of the 1-3 range this will let you know that a jet change is required and weather you need to order richer or leaner jets. Then count the turns from this point to bottoming out, if you take less than 3 and more than 1 complete turns to achieve bottom, the jet is correct and you simply wind back to the centre point. Wind back ½ the number of counted turns to the centre point. Follow this with 1/2 turn checks winding in one direction every 10 seconds till the engine starts to stumble, at this point then wind back in the opposite direction counting your half turns till it stumbles again. With your idle circuit, start at 1 1/2 to 2 turns out on the mixture screw and then wind your idle screw back to give a very slow idle whilst at operating engine temp with the bike upright. Here’s our simple outline for basic tuning to get you started. If at all in doubt, see your local tuning shop. Remember the tuning order is – idle circuit, then main jet and then finally mid range.
Please positively identify your jet type in the jets section, as all jet sales are final with no refunds.
Order required jets as your checks tell you. This is perhaps one of the best written book on carb tuning, just ignore the accelerator pump section if using a non pumper carb and remember that the mixture screw is an air screw where as on carbs with the screw located behind the bowl it will be a fuel screw in which case winding out is to make richer not leaner.īy following the procedures in the book you will determine if jets need changing and in what direction.
We recommend you down load the HSR tuning books for Harley Davidson. For tuning procedures we have a number of manuals available to the left.
0 kommentar(er)
