Triumph America and Speedmaster 865 or 790 Carburetor Kit Installation Guide

Step 1.  Begin by removing the gas tank, seat and then the chrome vanity air box boot cover shown below.  Some of you will remember when Triumph air filters looked like this vanity piece.

This picture shows the Triumph America and Speedmaster motorcycle chrome vanity piece and keihin carburetors.

Step 2.  Loosen the air box adapter band clamps on both sides of the motorcycle.

This pic shows Murray loosening the band clamps on a triumph america 790 to take off the stock carburetors.

Step 3.  Loosen the band clamps closest to the carburetors around the rubber isolator boots with a flathead screwdriver on each side.

This shows loosening the band clamp on the carb side of the triumph speedmaster america motorcycle.

Step 4.  Next, loosen the intake manifold bolts, and remove them.

This shows loosening the intake bolts on a Triumph Speedmaster America.

Step 5.  Remove the spacers between the cylinder head and intake manifolds.

This shows the removal of the spacers between the cylinder head, and intake manifolds on a triumph speedmaster.

Step 6.  Now remove the intake manifolds from the stock Keihin carburetors.

This shows the removal of the intake manifolds from the stock Keihin carbs on a Triumph America motorcycle.

Step 7. Disconnect the temperature sensor and bowl heaters from the bottom of the carbs.  Remember they are on both carburetors, and only pull on the connectors as the wires are quite small.

Disconnecting the temperature sensors and carburetor bowl heaters.

Step 8.  Now lets move to the throttle housing and remove the screws using a phillips head screwdriver.  Don’t forget to unscrew the cable screw as well.

This shows the removal of a Triumph Speedmaster America throttle housing.

Step 9.  Separate the two halves of the throttle housing and remove the cable ends from the plastic throttle tube releasing it from the housing.

Removing the cableends from the throttle housing on a triumph speedmaster america motorcycle.

Step 10.  Next, temporarily remove one of the coils from the frame to make space for the cables to be removed. Once the stock cable is removed reinstall the coil to the frame as they were.  We will not be routing Murray’s cable in the same way.

Removing a Triumph motorcycle coil driver to make room for the throttle cables to be removed.

Step 11.  Now that the cable tension is loosened remove the carbs from the air box boots and remove the air box boots completely from the air box.  These will be replaced with Murray’s Triumph air box boots in a moment.  While removing the air box boots rest the OEM carburetors on the crankcase.

Removal of Triumph Speedmaster America air box rubber boots.

Step 12.  Disconnect the TPS (Throttle Position Sensor) connector from the wiring harness and tuck the wires out of the way.

Disconnecting the TPS switch from the wiring harness on the Triumph Speedmaster America OEM carbs.

Step 13.  With all the wires now disconnected we can now use a wrench to release the stock cables from the stock carburetors.

Removing the throttle cables from the throttle body fixture on a Triumph Speedmaster America.

Step 14.  Now the Triumph OEM carburetors can be completely removed from your motorcycle.  You can take this time to tuck away and clean up the TPS switch, temperature sensors, and bowl heaters.  We will not be using these with Murray’s Carbs.

Now the OEM Triumph carburetors are removed and the wires can be cleaned up and tucked away.

Step 15.  Hold your new carburetors below the splitter and straddle the cable and carbs over the frame rail of your motorcycle.  One car on one side and the other carb on the other side.

Draping Murray's Carbs over the frame rail of your Triumph so that one carb is on the left and one is on the right.

Step 16.  It is now time to install Murray’s air box boot adapters.  Take notice of the “UP” indicator before going further.

Showing the UP indicator marks on Murray's Triumph air box boot adapters.

Step 17.  Put a bit of grease on each carburetor back.

Applying grease to the back of the Mikuni carburetors.

Step 18.  After the grease has been applied, gently press on the air box boot replacements to the back of the carbs.  Take time to make sure the “UP” indicators are facing UP.

Pressing Murray's greased air box boots onto the MIkuni carbs gently.

Step 19.  With the clamps loosened press the genuine Mikuni Spigot to the cylinder head side of the carburetor.  You will feel it snap into place.  Leave this loose, but in place on the carb so it can be aligned later.

Loosely attaching the Mikuni spigots to the cylinder head side of the carburetors.

Step 20.  Use a bead of RTV silicone or grease on the outside lip of the air box boots to ensure an airtight seal on the air box.

Applying a bead of RTV silicone to the air box adapter boots for Murray's Triumph Speedmaster Carburetor Kit.

Step 21.  Next, press the air box adapters into the air box gently.  You will feel the snap into place as they seat in the recess.  Make sure the “UP” indicators are still upwards.  This will ensure proper alignment of the kit to the cylinder head.  Please note it is important to install the right carb first. Do not install the left side carb until this one is completely in place.  

Pressing Murray's air box adapters into the air box on a Triumoh America Speedmaster 790 or 865.

Step 22.  Apply grease to the o-rings and o-ring land on Murray’s custom tuned intake manifolds.  This will aid in keeping them in place while inserting the manifolds into place between the Mikuni spigots and cylinder head.

Applying grease to the o-rings for Murray's custom tuned Triumph motorcycle intake manifolds.

Step 23.  Now install the right intake manifold using the M6 x 20mm Hex Bolts.  When threading the inside bold you’ll understand why we said to do the right side carb first. This allows you the space from the left side of the bike to snug the inside bolt down.

Threading in the bolts to Murray's Triumph Speedmaster America and T100 intake manifolds.

Step 24.  Twist the Mikuni Spigot adapter to align it with the intake manifolds.

Twisting the Mikuni spigot into place during the install of Murray's Carbs.

Step 25.  Now install the provided 10mm bolts to secure the Mikuni spigot to the intake manifold.  Its best to start them by hand then snug them with a wrench.

Installing the included hardware for Murray's Triumph America Speedmaster 865 and 790 carburetor kit.

Step 26.  Snug up the Mikuni spigot band clamp, and you are ready to install the left carb in the exact same order.  Go back to the beginning of these instructions if you have forgotten the steps.

The left side of Murray's aftermarket performance carb kit for Triumph and America is now installed.

Step 27.  Once the right carb has been installed it is time to replace your stock Triumph air box lid with Murray’s high flow version.  First uninstall the wire cover with the Triumph logo shown in the picture below by taking out the phillips screw circled in green.

Removing the stock Triumph Speedmaster America airbox to replace it with Murray's Carbs high flow version.

Step 28.  Now remove the 3 other screws to remove the original air box lid and set it off to the side.

Removing the last remaining screws to remove the stock air box lid on a triumph america speedmaster.

In the picture below Murray shows a side by side comparison of the stock lid and our performance one.  The airflow is greatly improved by this modification.

Comparison of Murray's high flow air box lid and the restrictive Triumph version.

Step 29.  Just set your new high flow air box lid in place, put the screws back in and screw the Triumph wire cover back into place.

Murray's highflow air box lid installed on a Triumph Speedmaster America.

Step 30.  Now you can connect your new throttle cable to the throttle housing.  Please remember the cable should be routed on top of the frame, through the left fork, around the headlight, and to the throttle housing.  Any kinks, harsh bends, can cause issues.  If you run into any issues please call us using the contact information at the bottom of each and every one of our webpages. Now, you can reinstall your chrome vanity pieces, tank, seat, and go for a ride.  Enjoy!

Picture of Murray's performance MIkuni carb kit for Triumph America and Speedmaster motorcycles.