Linkert Carburetor Overhaul Instructions
When dismantling the carburetor take care not to damage the body as it is made of Bronze. When removing the choke lever and ratchet assembly from the body, quite often the tension ball anchor has become worn in the body causing the ball and spring to fly out when the choke lever assembly is removed. Slide assembly out very slowly ensuring the ball and spring is contained (does not go flying). Disassembly and cleaning Disassembly is pretty straight forward but make sure you disassemble the carburetor down to a bare body (remove all plugs, etc). Throttle shaft bushings can be left in if they are serviceable. Soak in a suitable carburetor cleaner for some time. When removing the choke lever assembly, it is not uncommon for the choke ratchet ball and spring to no longer be firmly retained in the carburetor body. Remove choke lever assembly very slowly making sure the ball and spring does not go flying. Pass a wire or softish rod (brass brazing wire) down all the holes to ensure they are thoroughly clean as baked in crud can lodge deep down in some of the holes. Blow out with compressed air afterwards to ensure all passageways are clear. If bead or other media blasting has been performed it is important to thoroughly scrub everything clean in hot soapy water. Solvents do not remove glass bead. Glass bead is the #1 killer of engines and any glass beads left behind will get into your engine and cause premature failure.
Throttle Shaft Bushing Removal:
Removing the throttle shaft bushings from their blind holes is a little tricky as they cannot be pressed through but rather has to be backed out. This requires the use of a 5/16-NC taper tap in order to remove it. Thread the tap into the bushing several turns until you feel it has plenty of engagement. Do not wind tap in too deep as you may break through the outside diameter of the bushing and damage the body. Insert a piece of 1/4" diameter rod from the opposite end and with a small hammer tap the rod which in turn will remove the bushing (see pic). Repeat likewise for the remaining bushing.




Body Assembly Throttle shaft Bushings: Press bushings into body (lube with oil) until they are flush with the body. Do not tap bushings into position, only use a press. Ream bushings to size so throttle shaft moves freely.

Body Plugs:
Install the small body passageway plugs into the carburetor body.

Body Idle Plug:
Fit body idle plug into the body however there are several different styles and each one effects the proper running of your engine. The 2 main styles are either flat or have a raised titty. The flat one refers to no titty at the end of the threads while the titty one has a raised 3/16 titty which is 3/16 in diameter. The one that matches the 344 model carburetor is the titty plug.


Body Assembly Throttle shaft Bushings: Press bushings into body (lube with oil) until they are flush with the body. Do not tap bushings into position, only use a press. Ream bushings to size so throttle shaft moves freely.

Body Plugs:
Install the small body passageway plugs into the carburetor body.

Body Idle Plug:
Fit body idle plug into the body however there are several different styles and each one effects the proper running of your engine. The 2 main styles are either flat or have a raised titty. The flat one refers to no titty at the end of the threads while the titty one has a raised 3/16 titty which is 3/16 in diameter. The one that matches the 344 model carburetor is the titty plug.


Venturi: The venturi should fit snuggly inside the body however some originals are worn and have become loose. These should be replaced. Outside clearance should be kept to a absolute minimum and should barely be able to slide in and out. The correct venturi for Indian carburetor bodies has a 5/16" slot at the choke end at the bottom which is visible when being viewed from the choke end. This is an air bleed passage and is important. Some venturi's on the market do not have this air bleed passage as they are designed to fit Harley carburetors. There are several different inside diameters and the following chart will offer some good advice. At this stage it is optional to fit the nozzle, nozzle spring and bowl however by installing it now will locate and hold the venturi in its place. Since there is no obstruction at each end of the carburetor (no throttle or choke butterflies installed yet) it is an ideal time to easily access and position the venturi in relation to the nozzle especially if it is a little snug. The nozzle tip should stick up approx 1/4" above the venturi when assembled.
The nozzle is to protrude through the hole in the venturi by approx 1/4". The stock nozzles are best suited for most peoples riding conditions. This nozzle can be identified by the holes that are drilled into the flat vertical section of the nozzle. See Parts Match Up Recommendations for Chief Models section. Nozzle spring fits to the bottom side of the nozzle with the bowl nut holding it into place. Nozzle flat is to face the choke end of the carburetor. Nozzle spring is to fit to the bottom end of the nozzle and bowl nut.
Throttle Shaft:
Measure throttle shaft for wear as it is usually worn. It is suggested to replace it with a new one since a good fit between the bushings and throttle shaft reduces air leaks which is a common problem. Fit throttle shaft from bottom end of carburetor ensuring it turns freely (no binding).



Throttle Disc: Fit throttle disc so as the #13 is on the right side facing outwards and center disc within the body. Ensure the 2 #6/32 screws have lock washers fitted to them so as they do not come out during service (which will cause severe engine damage). When the disc is in the closed position there should be no air gaps surrounding the disc in the body. Throttle Shaft Tension Spring: Fit tension spring to top side of throttle shaft. Large diameter sits against the carburetor body small end fits against bellcrank. This tension spring is very important as it eliminates wear caused by engine vibration between the disc and body. These usually see a lot of wear during service and it is recommended to replace this spring in order to restore the original tension.
Throttle Bellcrank:
Slide bellcrank into position so as there is tension on the spring yet the shaft is still able to rotate freely without any binding.
Throttle Disc:


Fit choke shaft assembly into position and install D cam and #8/32 nut and lockwasher. When installing the choke ratchet after the ball and spring is no longer firmly retained in the carburetor body, it will be necessary to compress the ball and spring into the body with a very small screwdriver (or credit card) and carefully slide the choke lever assembly into place. Exercise caution as it will not take much for the ball and spring to go flying. For this reason we do stock new balls and springs.
Choke Disc:
Slide Choke disc into position with the hole at the bottom. Ensure disc is centered within the body when in the closed position. Ensure the 2 #6/32 screws have lock washers fitted to them so as they do not come out during service (which will cause severe engine damage). Low Speed Needle Spring Seat Disc: This disc is very important as it acts as an air bleed regulator and directly affects the proper running of the engine and must be matched up to the correct carburetor. There are 2 flange thickness which relates to the internal hole size. The overall height of both of these discs are the same so the thickness that is being referred to is the outside flange thickness (the section the spring sits on). The thickness does not mean anything other than it relates to the center hole inside diameter. See Parts Match Up Recommendations for Chief Models section Needles General Information: Check that the high speed and low speed needles are not bent and that the taper ends are not damaged. Bent needles can be straightened however needles with damaged points should be replaced. Hi Speed Needle: When fitting this needle, ensure that when the taper end is all the way down onto its seat that there is still a gap between the bottom of the knob and carburetor body. There are several length needles (that fit different carburetors) and it is not uncommon to have one that is mismatched and too short that will bottom out on the carburetor body. This will affect the proper tuning adjustments since when the needle is turned all the way in it will still run rich (as the needle point will be off its seat) and you will be left wondering why your tuning will not give the desired results. Low Speed Needle: The low speed needle has a tension spring built inside the knob. This can be checked by compressing the needle (by hand) into the knob. Exercise caution as 1 little slip can cause severe bodily injury. You should feel and see it movement. If it does not move easily it will be necessary to disassemble the knob and repair as necessary.
Float Bowl Assembly:
Ensure bowl nut washer face (on bottom of bowl) is free of pits and grooves. Sand or machine as necessary. Fit bowl drain screw and sealing washer. It is recommended to fit a new float lever and lever pivot pin as these items usually see a lot of wear during service. There are 2 types of floats available with the latest being a light weight composite type which is compatible with current fuels. The other is a brass float. Both are good and have their advantages and disadvantages. Brass floats are heavier than composite floats therefore requiring a different float height setting. Some brass floats threaded screw hole do not stop at a blind hole which can cause gas to leak down the threads and fill up the float causing it to sink. If your float is of this type the screw threads must be sealed with a gas resistant thread sealant. The float sideways position within the bowl can vary and should be positioned as follows: Loosen the float lever screw. While looking down into the bowl with the needle and seat end positioned at 12 oclock, pull the float towards the 6 oclock position (usually to the outmost part of the slot) and move it about 1/16 towards the 9 oclock position (slightly off center to the left). Tighten float lever screw. Make sure outside diameter of float does not make contact with the float bowl otherwise it may hang up and cause flooding. Likewise if it hangs up on the carburetor center snout portion as it too will cause flooding. Note: Some replacement bowls have been made incorrectly and are too small on the inside diameter and some others have a rough finish. Both of these can cause the float to hang up however the rough finish bowls can be reclaimed by sanding the rough spots smooth. Bowls that are too small should be replaced with the correct one. Float height is to be as follows and is measured from the top surface of the bowl and with the bowl turned upside down (so the float hangs downwards). Ensure needle seat is tight in the bowl before adjusting otherwise an incorrect measurement will result. Brass float is 5/16" while composite/cork (light weight) float is 1/4". Adjusting Float Height: 1st off the float lever fingers must have minimal clearance between it and the float needle. Bend fingers to achieve minimal play. Any excessive clearance here will give a false indication of the true float height and create a lean mixture as the float bowl will not be kept full at all times. Check for smooth sliding operation through out its movement. Sometimes it is necessary to remove burrs, hickys and wear grooves on the fingers with a small fine file. When adjusting the float height, the float lever itself must be bent but it must be done when removed from the carburetor. Bending while still in the carburetor will bend the fingers at the opposite end. The area that is to be bent is between the float lever screw hole and the float lever pivot shaft hole. You will notice this area is narrower and weaker than the rest of the float lever just for this purpose. Ensure float is not cock eyed height wise in the bowl. Tweak/level as necessary. Final tighten float level pin plugs. Fit plug above needle and seat.




 Fitting Bowl to Body Fit gasket between top of bowl and carburetor body. While the factory did not use a gasket, it is recommended to fit one as it reduces the chances of water entering into the bowl or gas from spilling out when the bike is on an excessive angle. Fit bowl until it seats against the bowl gasket making sure the fuel inlet (needle seat side of the bowl) is facing forwards towards the front of the bike. Insert nozzle and nozzle spring making sure the nozzle flat faces towards the choke end. Fit copper or fiber bowl nut washer and bowl nut. It is highly recommended to use a copper bowl nut washer as this is more forgiving and does the best job of sealing. Parts Match Up Recommendations for Chief Models: Body Idle Plug: Titty or flat. Most Indian carburetors require the use of the titty plug. At this time there is no complete listing (other than what we have studied) however over time we will assemble a chart as the which plug fits which body. Low Speed Needle Spring Seat Disc: There are 2 sizes of inside diameter holes, .106 and .111. The outer flange thickness relates to the hole size (.066 or.036) and has nothing to do with spring tension as commonly thought as it is only a visual way of identifying which hole size is which. The thick disc has a flange thickness of .066 (approx 1/16 and is referred to as the thick disc) and a .111 diameter hole while the thin disc is .036 thick (approx 1/32) and has a hole diameter of .106. Both discs have the same overall height. 344 carburetors use the thin disc. Venturi Size: 1-1/16: Stock and normal riding for 74" engines. Best for low to mid range up to approx 3000 rpm. This range is where the greatest majority of riding is done. 1-1/8 is better suited for 80", 84" and Bonneville 74" engines. Fitting a larger venturi than necessary will reduce bottom end and mid range power. Nozzle: Generally the best all around nozzle is the stock nozzle however for higher revving engines Bonneville nozzles should be considered. Stock 74" nozzle can be identified by the 5 small diameter holes in the flat portion starting from the bottom and moving upwards (bottom being the bowl nut end). Bottom hole is #44 drill size, #2 hole is #48 drill size, #3-5 (5 being the upper most hole) #57 drill size. A Bonneville 74" and 80" nozzle will have 2 extra angle cuts machined in either side of the flat portion. Show pic. Note: By installing the Bonneville nozzle in your stock 74" it will diminish its low to mid range power therefore it is important to match the nozzle with the correct venturi and style of riding that you will be doing. Float heights: Over the years different materials have been used to manufacture floats with varying success due to the ever changing formulas of modern gases. Some of these materials require different float level heights. Brass floats are to be set at 5/16" while composite/cork (light weight) floats are set at 1/4". General Notes: There is very little data on some of the above parts available and to make matters worse there were several models of Linkerts that were made for after market parts suppliers that were used as replacements for Indians back in the day. These generally have a serial # like M6A, M6SA, etc and usually has Indian stamped into the body. To matters worse, parts get changed out and mismatched over the years. We will continue to compile data in order to make a comprehensive listing. For this reason please check our website for the latest information.​


Tuning the Carburetor The following was compiled so you can dial your carburetor in easily and properly. All final adjustments must be made with the engine thoroughly warmed up and make all adjustments slowly giving the engine time to respond to the setting adjustments.​


1. High Speed Needle Valve


2. Low Speed Needle Valve

3. Choke Lever


4. Idle Speed Screw

Turn both needle valves clockwise until they seat using caution not to over-tighten as it may damage the needle valve or seat. Turn the high speed needle valve (valve towards the front) counterclockwise 1-1/2 turns. Turn the low speed needle valve (valves towards the rear) counterclockwise 3 to 4 turns. Both these settings are good starting points. Start the engine and thoroughly warm up making sure the choke lever is fully open before starting on any following fine adjustments. With the engine at an idle (throttle closed position), fully retard the spark and adjust the low speed by turning it either clockwise or counterclockwise until the engine smoothes out and fires evenly. Turning this valve clockwise gives the engine a leaner mixture while turning it counterclockwise gives it a richer mixture. Rev the engine up to about throttle and hold steady at this rpm to adjust the high speed needle valve. Turn the high speed needle valve clockwise until the engine starts to falter. At this point turn needle valve counterclockwise until the engine runs at its fastest speed. Check this adjustment by retarding the spark and opening the throttle. If the engine backfires through the carburetor it indicates a too lean a mixture and the needle valve should be turned counterclockwise a little. If the engine chokes when the throttle is opened, it indicates a too rich a mixture and the high needle valve should be turned clockwise. When making each adjustment, slowly turn needle valve a notch or 2 at a time giving the engine time to respond. Once settings have been finalized note the needle valve location so as you can return to it if anything should happen. Although the high and low speed needle valves operate independently, they do affect each other. For this reason, return to the low speed needle valve and readjust as in step 4. Adjust idle speed by adjusting the screw on the throttle shaft bell crank. Turning it clockwise increases the engine speed while turning it counterclockwise decreases engine speed