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Triton L4, L5  Tuning guide
Triton L4 & L5 engines tune differently than many other brand engines. On the Triton L4 and L5 the high speed needle makes up for a large amount of the engines performance from low end to top end so it is important to understand this so you can dial in the perfect race tune. Remember! No matter if you preheat an engine on the bench it will NOT reach operating temperature until it is run for a few laps on the track. So DON’T try and fine tune your engine on the box.The engine will Lean out when it gets up to temp after a few laps so  keep this in mind. Your engine should not “scream” as soon as you throw it on the track. It should take a lap or two to warm up and start screaming and for the idle to stabilize. If you fire it up and throw it on the track and it start screaming instantly chances are when it reaches operating temp it may be too lean.  A simple way to put it is the Triton likes a leaner top end and a richer bottom end. The idle gap is fairly close out of the box but for reference approx .65mm gap is good. (and easy way to check your idle gap if you have it out of adjustment is to remove the venturi and back OUT the idle screw to close the gap. Stop when there is no gap then turn the idle screw in 7/8 of a turn and this will be close to an ideal idle gap.)  Idle gap should be adjusted  first before trying to tune your engine. To start race tuning, tune the high speed needle first and when you think you have tuned it well on the high speed needle now go to the low speed needle. Richen the low speed needle slowly a little at a time until the engine stalls form being too rich. Now slowly lean out the low speed needle until the engine doesn’t stall and has a good stable idle and has good acceleration. Now run the engine on the track and check its performance. If there is crisp acceleration and power all through the powerband and a good smoke trail you have a good tune. If there is any sluggish/rich spots in the lower midrange or upper rpm’s then lean the high speed needle until the power is strong and crisp all the way through the powerband. ( lean is turning screws clockwise, rich is counter clockwise) Then go back and fine tune the low speed needle starting from overly rich then lean for stable idle and good off the line response. Dont make the mistake of overly leaning the low speed needle too much to try and gain low/mid performance as a lot of times it is the high speed needle that needs to be leaned out more to acheive this. On a hot day ( 90+deg F) it is normal for Triton temps to be approx 250-280f degrees  at a race pace. Factory  rich settings For origional 2 needle L4,L5 1st generation are approx flush on the high speed needle and 1/2 OUT from flush on the low speed needle. L4,L5 V2 ELITE 2 needle carb are High speed needle flush but low speed needle approx 1 1/2 turn out form flush. The 3 needle V2 Elite carb factory setting are flush on high speed and flush on lpow speed. 3 Needle  carb has a brass screw on the side of hte carb on the aluminum end bell. DO NOT TOUCH the Brass 3rd needle. It is preset. Only touch a tiny bit if you are a master tuner! These setting are only how the engine come when new. They are NOT tuned settings. You will need to fine tune your engine and each engine will have different settings so do not just copy settings from here or from another engine as even same engines settings will vary. Each engine must be tuned by its own to its own Performance. Race settings will vary but are usually around 1/2 - 1 turn IN  from flush on high speed needle on all L4 and L5  engines. Low speed needle will vary so sstart too rich and slowly lean until good idle and bottom end and use the “13 second rule” below. ( Flush means the screw is level with the brass housing on the high speed needle and on hte low speed it is level with the carburetor linkage housing SEE EXAMPLE pics below of (flush) Keep in mind these  race tuned setting are only approx to give an example. Settings can vary by 1 turn or more because of different fuel, climate, glow plug, pipe etc..... so Always tune to the engines performance. So always tune the engine to where it runs best and has a good smoke trail from the exhaust. A good way to check your low speed needle tune is with the engine fully at race temp go down straight full throttle, stop and make a U turn at the end of hte straight. Count to 13 then punch it down the staightaway.There should be a slighlt “puff” of smoke from the exhaust and a very slight hesitation from it idling for 13 seconds and slightly “loading up”. If it instanly screams with no little extra puff of smoke the Low speed needle is a little too lean. Ans if there is a big puff of smoke and big delay before it screams then the Low speed is a little too rich. This is becasue properly tuned engine will slowly load up with fuel at idle over time. Lance Heidmann Triton RC RcRenew
example of flush needle settings