4.8
Polaris Sales Inc.
4/99
FUEL SYSTEM/CARBURETION
Component Functions (2 Cycle)
Jet Needle
The jet needle has five adjustment grooves cut into the up-
per portion, and is tapered from approximately the middle
of the needle to the lower end. The top is fixed to the center
of the throttle valve by the needle clip, and the tapered end
extends into the needle jet. Fuel flows through the space
between the needle jet and jet needle. This space does not
vary until the throttle reaches the 1/4 open point. At that
time the tapered portion of the needle begins to move out
of the jet, affecting fuel flow as the opening enlarges. If the
needle clip is changed from the standard position to a lower
groove, the needle taper starts coming out of the jet sooner,
resulting in a richer mixture. Moving the clip higher pro-
duces a leaner mixture. If the taper is worn due to vibration,
fuel flow may be significantly affected.
Needle Jet
The needle jet works in conjunction with the jet needle to
regulate fuel flow rate. An air bleed opening in the side of
the needle jet brings in air measured by the air jet. This air
initiates the mixing and atomizing process inside the needle
jet. Mixing is augmented by a projection at the needle jet
outlet, called the primary choke. The letter number code
stamped on the jet indicates jet inside diameter.
Throttle Opening vs. Fuel Flow
In a full throttle condition the cross sectioned area be-
tween the jet needle and the needle jet is larger than
the cross sectioned area of the main jet. The main jet
therefore has greater control over fuel flow.
Needle Jet
Opening faces
engine
Washer
Main Jet
Small
Clearance
Medium
Clearance
Large
Clearance
Closed
Throttle
One-half
Throttle
Full
Throttle
Groove
Leaner
Richer
Jet Needle
Summary of Contents for Trail Blazer
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Page 186: ...3 41 Polaris Sales Inc 4 99 ENGINE 4 Stroke Engine Service ...
Page 187: ...3 42 Polaris Sales Inc 4 99 ENGINE Notes ...
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Page 318: ...5 17 Polaris Sales Inc 4 99 BODY STEERING SUSPENSION Shaft Ride Swingarm Exploded View ...
Page 331: ...NOTES ...
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Page 353: ...6 20 Polaris Sales Inc 4 99 CLUTCH Standard P 90 Non EBS Clutch ...
Page 354: ...6 21 Polaris Sales Inc 4 99 CLUTCH NOTES ...
Page 358: ...6 25 Polaris Sales Inc 4 99 CLUTCH This Page Blank ...
Page 371: ...6 38 Polaris Sales Inc 4 99 CLUTCH This Page Blank ...
Page 372: ...6 39 Polaris Sales Inc 4 99 CLUTCH ENGINE BRAKING SYSTEM EBS Clutch ...
Page 378: ...6 45 Polaris Sales Inc 4 99 CLUTCH This Page Blank ...
Page 382: ...6 49 Polaris Sales Inc 4 99 CLUTCH This Page Blank ...
Page 388: ...NOTES ...
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Page 398: ...This Page Blank 7 7 Polaris Sales Inc 4 99 FINAL DRIVE ...
Page 404: ...This Page Blank 7 13 Polaris Sales Inc 4 99 FINAL DRIVE ...
Page 429: ...7 38 Polaris Sales Inc 4 99 FINAL DRIVE Rear Drive ...
Page 453: ...7 62 Polaris Sales Inc 4 99 joints and CV joint boots ...
Page 462: ...7 71 Polaris Sales Inc 4 99 FINAL DRIVE Center Front Chain Tightener Exploded View ...
Page 463: ...NOTES ...
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Page 605: ...10 36 Polaris Sales Inc 4 99 ...
Page 620: ...ELECTRONIC SPEEDOMETER WIRING DIAGRAM PVT MODELS 10 51 Polaris Sales Inc 4 99 ...
Page 630: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Trail Blazer ...
Page 631: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Trail Boss ...
Page 632: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Xplorer 300 Xpress 300 ...
Page 633: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Sportsman 335 ...
Page 634: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Sport 400 ...
Page 635: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Scrambler 400 Early ...
Page 636: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Scrambler 400 Late ...
Page 637: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Xplorer 400 ...
Page 638: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Scrambler 500 ...
Page 639: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Magnum 500 ...
Page 640: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Sportsman 500 Sportsman 500 RSE ...
Page 641: ... Polaris Industries Inc 4 99 ELECTRICAL Wiring Diagram 1999 Worker 500 International ...
Page 642: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 1999 Big Boss 500 6x6 ...
Page 643: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Trail Blazer ...
Page 644: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Xplorer 4x4 ...
Page 645: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Trail Boss 325 ...
Page 646: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Magnum 325 2x4 ...
Page 647: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Magnum 325 4x4 ...
Page 648: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Xpedition 325 ...
Page 649: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Sportsman 335 Early ...
Page 651: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Xplorer 400 ...
Page 652: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Scrambler 400 2x4 ...
Page 653: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Scrambler 400 4x4 ...
Page 654: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Xpedition 425 ...
Page 655: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Magnum 500 Early ...
Page 656: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Magnum 500 Late ...
Page 657: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Scrambler 500 Early ...
Page 658: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Scrambler 500 Late ...
Page 659: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Sportsman 500 Early ...
Page 660: ... Polaris Sales Inc 99 00 ATV Update 12 99 ELECTRICAL Wiring Diagram 2000 Sportsman 500 Late ...