INSTALLING A BDL 2" OPEN BELT DRIVE ON AN EVO SOFTAIL
First things first, let's discuss the elephant that connects the left side of the EVO motor and transmission. That clunky inner and outer primary cover. A necessary component that houses your primary drive components, clutch, and starter motor.
Yet it's not the most sexy looking part on the bike and definitely not ideal when trying to make a lane splitter cool custom motorcycle. However there are a couple options to eliminate the stock primary assembly and add some reliability and performance at the same time.
The stock inner and outer primary is very bulky on an Evo Big Twin
One, you could eliminate the 5 speed transmission all together and go with a 4 speed ratchet top. This allows for the starter motor to go away and then you are looking at a kick only bike. There are options for belt drives from companies like BDL Belt Drives LTD. and smaller inner primary cases you could run.
But... with choosing this option, you are losing a gear and the electric start option completely. This option is also only on the table if you plan on fully dropping your motor into a different full frame, like a Gasbox Big Twin 4 speed full frame for instance.
It's just really bulky and not that great looking, but essential for keeping 5 gears and a starter motor.
Option two, which is a little more practical and would allow you too keep all of your main bike components, your stock frame, transmission etc., is to run an electric start belt drive kit.
Belt Drives LTD. (BDL) makes a 2" SS Belt Drive Kit for 1990-2006 Harley-Davidson Softails that actually looks great, works perfectly, and really does slim down that left side fat. This is a way cleaner and easier option that works great with your stock frame and or a Gasbox 5 speed full frame.
The big difference in size going with a BDL Belt Drive set up
WHAT COMES IN THE KIT?
This is everything that comes in the BDL 2" SS Belt Drive Kit.
WATCH VIDEO: HOW TO INSTALL BDL 2" OPEN BELT DRIVE PRIMARY
In this video Tim Fiorucci shows you how to install BDL 2" SS Belt Drive kit on Project Studd. Sharing every detail and giving helpful tips and tricks.
Though this bike is still in the mock up stage, he even shares the final assembly steps with you as he goes a long. You will get to see first hand the drastic change this belt drive gives on cleaning up the look of that bulky stock outer and inner primary case.
This is Project Studd a 1993 Softail put in a Gasbox Rigid Full Frame with BDL belt drive fully installed.
INSTALLING THE BDL 2" SS BELT DRIVE IN 13 STEPS
I asked for Tim Fiorucci's help on this install to help show everyone how to do this job properly.
NOTE: This kit will also work on a stock 1990-2006 Harley-Davidson Softail as well as a custom chopper. BDL states this kit was meant to replace and be used with OEM components. In this install it is being used on a full custom chopper build, but the install procedure is the same on a stock Softail.
The starter motor, primary cover, compensator sprocket, clutch basket/hub and inner primary have all been removed. The motor and trans mounting bolts have been loosened up.
STEP 1: REMOVE STARTER MOTOR, PRIMARY COVER, COMPENSATOR SPROCKET, CLUTCH BASKET/HUB AND INNER PRIMARY
If you haven't done so already the first step is to remove your starter motor. Next you will want remove the stock outer and inner primary cases. Follow along in your workshop manual and remove these components. The outer primary cover, the clutch basket / hub, the compensating sprocket, primary chain, inner primary case, the large O-ring on the motor, and the inner main shaft bearing race.
NOTE: the main shaft on your transmission is reverse thread. Make sure you are going the opposite direction to take that nut off on your clutch basket/hub. Going left is only going to tighten it more and you could break something.
Remove the Engine O-ring.
Removed the O-ring off the engine.
Here is the inner stock race location on the main-shaft. This will not work with the BDL inner primary so it needs to be removed with a special puller tool. 
You must use a puller to get the inner race off the main-shaft. Be sure to remove the pushrod from the main shaft first before using the puller.
Place the step behind the inner race and thread in the puller. Get as much thread engagement as you can on each of the puller bolts.
Use a crescent wrench to hold on to the puller and a socket wrench to tighten the middle shaft and it will begin to pull off the inner race slowly.
Once it reaches the splines it should slide right off.
You will also need a special tool to remove the inner bearing race on the main shaft of the transmission. Once removed use Red Scotchbrite to clean off the main shaft of any residue. After its clean, add a little bearing grease to the portion of the shaft where the inner race was. This will help the new inner primary with it's bearing already installed slide on easily.
Use red Scotchbrite to clean the main-shaft surface the inner race was riding of any residue and then apply some grease.
STEP 2: MAKE SURE ENGINE AND TRANSMISSION MOUNTS ARE LOOSE
Make sure your engine and transmission mounts are loose. You should be able to wiggle the engine and transmission on their mounts a little bit left and right.
This is a very important step. You want to make sure your engine and transmission mounts are all loose and you are able to move both of these around easily on the frame mounting locations. This will help you line up the new inner primary for the BDL.
Engine mounts loose.
Transmission loose and can move back and forward.
STEP 3: INSTALL THE POLISHED INNER PRIMARY
Be sure your shifter arm is installed before moving forward to this step.
Before doing this step you want to first make sure your shifter arm is in place on the transmission. You wont have room to slide this on after the fact. This is also a good time to be sure you have the front sprocket you want to run on your bike. Whether you are continuing to run a belt or if you want to run a chain conversion kit. Now is the time to make these decisions. Also if you are running a belt have that installed onto your rear wheel and pulley.
Looking at the inside of the motor part of the polished inner primary, it has no step for the O-ring on the engine. This is why it had to be removed.
Starting on the transmission side makes it a little easier to line up and slide on to the main-shaft.
Use your hands to push and tap on each side to line everything up. You shouldn't have to beat anything on, it should slide on nicely.
Starting with the transmission side, slowly slide the polished inner primary onto the main shaft, this is a perfect fit and should slide on nicely, do not bang with hammer and DO NOT draw the inner primary in with the fasteners. You want to gently tap with your hands the inner primary and move the transmission and motor to get all of your holes to line up and the inner primary to sit flush with the motor and transmission.
It is extremely important to not use the fasteners to draw the inner primary flush, this could cause pulling and tension in the case leading to cracking the motor or transmission cases. If it is not sitting flush, stop regroup and check for burs on your engine and transmission case, or you may have forgot to take the engine's large O-ring off.
You want the inner primary to be sitting flush against the motor and transmission before putting any bolts in.
Make sure to use blue Loctite with the bolts. Four black oxidized bolts go in the transmission.
The 4 clear Zinc bolts go into the motor.
Once everything is flush you will want to use blue Loctite on the fasteners. The four clear zinc-plated bolts will go to the motor and the four longer black oxidized bolts will go in the transmission. You will want to torque these down evenly, the workshop manual states these should be torqued to 18-22 ft lbs.
With these bolts we suggest to start at 15 ft lbs. and torque down a couple on the motor, then the transmission, then back to the motor and back to the transmission again, making sure everything is torqued evenly. Then go up to 22 ft lbs and again torque evenly all 8 bolts.
Evenly torque each of the 8 bolts down. first to 15 ft lbs.
Then go around them again and torque them to 22 ft lbs.
Once all 8 bolts have been torqued to its proper specification you will want to now torque down your motor and transmission mounting bolts. Our work shop manual recommended 33-38 ft lbs for all motor and transmission mounting bolts. Again always refer back to your work shop manual for torque specs.
Torque your motor and transmission mounting bolts down to 33-38 ft lbs.
STEP 4: INSTALL THE CLUTCH BASKET
When installing the clutch basket / hub onto the main shaft BDL recommends slathering the splines of the main-shaft and clutch basket inner splines with red Loctite. We would only recommend doing this in final assembly. If you are in mock up stage like we are here, do not do this until final assembly.
Before sliding the clutch basket on to the main shaft make sure you have carefully remove the pressure plate and fiber/steel clutch plates. Set those to the side for the moment and be careful not to accidentally loose any ball bearings from the pressure plate.
Getting ready to slide on the clutch basket / hub.
The clutch basket should slide onto the main shaft with ease. You will feel it seat. Loosely install the nut, remember reverse threads. Absolutely DO NOT hammer this on at all, this should be an exact fit and will slide on firmly. If it is not you might have an aftermarket main shaft or you are not using the right year range kit. Hand tighten the main-shaft nut on.
If you line the splines up properly, this should slide on like butter and you will feel it seat properly.
STEP 5: INSTALL THE FRONT PULLEY AND BELT
Reuse the stock spacer on the compensator shaft.
The front pulley has a few parts that go together. First make sure to install the stock spacer that rests on the compensator shaft of the motor and against the stator rotor. Next you will take the black machined spacer with the splines and slide it on the compensator shaft of the motor. This is an exact fit as well on the splines and will be a little hard to line up, but once you do it will slide on like butter. Again no beating this on! If its not fitting properly inspect and regroup.
Line up the splines on the machined black front pulley spacer and again it should slide on like butter.
Hand tighten the main-shaft nut on to the basket if you haven't done so already. This way the belt doesn't pull off the basket when you are fitting everything up.
Next, you will want to grab the belt and wrap it around the clutch basket then take the front pulley with the belt around it and line up your holes. The three larger holes are for the bolts with washers, the three smaller are for the roll pins. You can rotate the clutch basket / belt to help you align the holes on the front pulley to the machined spacer. Use Blue Loctite on the three bolts with spacers loosely.
Lining up the belt.
Setting the front pulley into position over the compensator shaft and machined black spacer. You can rotate the belt and clutch basket to help line up the holes on the pulley to the machined black spacer.
The three large holes pointed on left of this photo are for the 3 black oxidized bolts with spacers and the three smaller holes pointed on the right of this photo are for the roll pins.
Install the compensator nut hand tight. Next torque down the three bolts to 18-22 ft lbs. Again check your work shop manual for the recommended torque spec.
Loosely install the compensator nut to secure the front pulley.
Torque down the three bolts to 18-22 ft lbs.
Install three roll pins into the smaller holes. If you don't have the specific tool to do this job, you can use a small socket that is close to the size of the roll pin to help you align it properly, and use an extension attached to the socket to hammer them in. *Note only do this on finally assembly, if you are in mock up stage it makes it a lot easier to take apart and put back together when the roll pins aren't installed
If you don't have a special tool for roll pins, you can use a small socket that will help line them up and a socket extension to hammer them in. Only do this in final assembly, it will make your life easier.
You can now take an impact to lightly secure both compensator and main-shaft nuts. Remember front nut is standard thread and the nut on the main-shaft of the the transmission is reverse thread.
Lightly impact the compensator nut onto the front pulley.
Lightly impact the main-shaft nut on the clutch basket. Remember this is reverse threads!
STEP 6: INSTALL YOUR CLUTCH PLATES
This is how your clutch plates should be stacked. Thickest steel in the back, then fiber, steel, fiber, steel, on repeat and it will end with a steel.
This is super simple step but an important follow the pattern and pay attention. To install your clutch plates there is a specific order they must go in. The very first plate will be the thickest steel plate with the teeth facing towards the center. Next will be what is called a fiber plate and the teeth are facing outside of the plate. You then just repeat this pattern, steel, fiber, steel, fiber, steel, fiber until you end with a steel at the end.
Thickest steel plate goes in first.
Then fiber, steel, fiber steel, until you run out.
STEP 7: TORQUE DOWN THE MAIN-SHAFT NUT
We got to torque this bad boi down to 70-80 ft lbs.
Theres more than one way to skin a cat as some may say with this kind of stuff. There is a special clutch basket locking tool you can use to help lock up the clutch basket to torque down the nut properly. We didn't have that tool at this time, so here is another helpful way to do this job. Put your chain on your front and rear sprocket, put the bike in gear and ratchet strap your wheel to your work bench. We were able to ratchet strap the sprocket to our build table. Then torque the main-shaft nut to 70-80 ft lbs. Remember the main-shaft nut is reverse threads! Don't forget to use blue Loctite.
We put the chain on and also ratchet strapped the sprocket/wheel to the build table so that it couldn't move.
Torque that son of a gun down.
STEP 8: INSTALL PUSHROD, PUSHROD ADJUSTER / MAIN-SHAFT SEAL AND PRESSURE PLATE
Lube up your pushrod with some Molly lube.
Lube up your pushrod with some Molly lube and insert it into the main-shaft.
Installing the pushrod into the main-shaft.
Next take the pressure plate and install the pushrod / main-shaft seal by threading it in through the back of the plate. Be careful not to allow the pressure plate go vertical and separate from the backing plate, there are a ton of ball bearings loose inside of it that will go all over your shop. Apply some grease onto the o-rings of the main-shaft seal and push the entire assembly into the main-shaft.
Install the adjuster / main-shaft seal into the back of the pressure plate and screw it in so that the adjuster nut has a lot of threads in the front.
What your pressure plate will look like when you put the adjuster / main-shaft seal into the pressure plate.
Installing the backing plate of the pressure plate into the main-shaft. Add a little grease to the O-rings of the main-shaft seal to help guide it home. Make sure not to let go of the diaphragm once vertical because you will lose all of the ball bearings underneath.
Next hand tighten each of the six screws of the pressure plate by hand. Don't forget to use blue Loctite. It's easier to screw one in at a time. Screwing one in at a time by hand also helps with holding the pressure plate to the diaphragm with your other hand. The last thing you want to do, is lose all of the ball bearings that ride underneath of the diaphragm.
Once all 6 bolts are in place tighten them down evenly in a star pattern with a T-handle. They are shoulder bolts so you will feel a positive stop in the hub where they can't be tightened any further.
Continuing to hold the diaphragm in one hand you can line up your holes and install the pressure plate with the 6 shoulder bolts.
It helps doing one at a time so that you can keep pressure on the diaphragm with your other hand.
Once you get all 6 shoulder bolts in. Tighten them down in a star pattern evenly. You will know when they can go any tighter, because its a shoulder bolt there is a positive stop you will hit.
STEP 9: ADJUSTING YOUR CLUTCH
Make sure you have your clutch cable installed on the transmission and in your clutch lever on your bars. Break the adjuster nuts free and make sure you have the most amount of play in the cable. On the pressure plate you are going to run the center adjuster screw / main-shaft seal into the main-shaft until it hits the pushrod. When you hit the pushrod stop and turn back the adjuster a half turn. While holding in that spot with your T-handle, lock the nut down with a wrench.
Make sure to have your adjuster locking nut on and run your adjuster in.
When you feel it get a little harder you have hit the pushrod, back off the adjuster a half turn.
You will know when you hit the pushrod because it will get firmer, if you keep turning it in, you will actually see the pressure plate move as well and you have gone too far. If that is the case, back it off until it feels loose again and then turn it back in until you feel it firm up again into the pushrod. Back it off half a turn and lock down that nut!
Once you get back half turn, secure the locking nut in that position.
Next go to your clutch cable adjustment and adjust it to until you have about an 1/8" of free play in the lever. Lock down your adjuster nuts on the cable. With the transmission in gear if you pull the clutch lever into the bars the clutch basket should move freely and when you let go of the clutch the basket should engage and not be able to move.
If It is not moving when you pull in the clutch lever, something is wrong and you will have to redo and readjust. One problem that could arise is one of the clutch plates could have accidentally fell off the teeth of the basket and be sitting crooked when initially installing, so be sure to check for that.
Adjust your clutch lever and lock down those adjuster nuts.
When your clutch lever is pulled in you should be able to move the clutch basket freely.
STEP 10: TORQUE THE COMPENSATOR NUT
Now that the clutch is in place and in gear, with the chain still locked down we can torque the nut on the front pulley aka the compensator nut even know its not a compensator anymore. We didn't have the special tool that locks the clutch hub in place so we are using a piece of wood that we cut down to lock the two pulleys in to one another. Remember to use blue Loctite and this one calls for 150-165ft. lbs.
We didn't have the special tool to lock the hub so we cut a piece of wood.
Torque the compensator shaft nut down to 150-165 ft lbs.
STEP 11: REMOVE AND REPLACE STARTER COMPONENTS
When you pulled your starter motor it will look something like this.
It will also have this sleeve with splines inside that will feel stuck on the bendix. Use a set of vice grips with a slide hammer attached to it to remove this.
First you will want to remove the old pinion gear and sleeve off of the starter motor. These will not work with the BDL belt drive set up. There is a sleeve with internal splines that is kind of a press fit. You can use a set of vicegrips with a slide hammer on the end to easily get that off.
Exploded diagram from BDL of the Starter Motor stack up needed to work with the starter motor parts they supplied in the kit.
There is an exploded diagram included in the kit to show you how to put the new pinion gear set up on the starter motor. The stack up is the same no matter what year bike you have but there is one difference in the two bolts that are supplied in the kit. If you have a 1990-1993 you will use the 1/4"-20 bolt and if you have a 1994-2006 will use the 10-32 bolt.
First is a splined washer, next a spring and then the pinion gear with the gear side furthest from the starter motor.
Next is the pinion gear tube followed by a top hat and then the corresponding bolt size for your year range. ours is a 1993 so we used the 1/4"-20.
The stack up goes as follows. The splined washer goes onto the shaft. The spring goes on top of the washer. The pinion gear goes on top of the spring with the gear part furthest away from the starter. The pinion gear sleeve tube goes inside of the pinion gear. The top hat goes on top of the pinion gear. Lastly the bolt for your year range secures everything together when screwed into the shaft. Again use blue Loctite.
Torque down the pinion gear and don't forget to use blue Loctite.
STEP 12: INSTALL THE STARTER AND STARTER CAP
On the right side of the bike above the transmission you will see where the starter motor goes. There is a dowel pin that will help you locate the starter motor in correctly and torque down the two bolts.
On the right side of the bike you will install the starter above the transmission. There is a dowel pin to help keep it inline on the transmission. Using your stock bolts that go from the starter to the transmission, torque them down 18-22 ft. lbs. and use blue Loctite.
Starter motor installs with two bolts, torque them down 18-22 ft lbs.
Swing back to the left side of the bike and install the starter cap with the remaining two clear Zinc bolts from the kit. Inside the cap you will notice a race that the pinion gear rests in when the starter is actuated. The cap needs to be mounted flush on the inner primary so that this lines up that pinion gear properly. Torque these to 18-22 ft. lbs. and use blue Loctite.
You can see on the starter cap, there is a bushing inside the back, this helps the starter motor pinion gear align properly to crank the clutch basket / engine.
Use the last two clear Zinc bolts that were included in the kit to install the starter cap. You want to make sure the lines of the cap and the Inner primary are flush for best alignment of the pinion gear / bushing on the cap.
Subtle branding BDL Belt Drives on the starter cap installed.
STEP 13: FINAL CHECKS
If you used red Loctite on the splines of the clutch basket on final assembly, be sure to let this dry for a few hours before starting up the bike and taking it for a ride. The last thing you want is red Loctite flying around on your clutch plates.
Make sure to hook up your starter motor wiring back to your bike.
Again test that the clutch is working properly when you pull in your clutch lever. Make sure the hub is moving freely when you pull it in, before starting the bike.
So much cleaner looking. Starting to look like a chopper!
BDL 2" SS Belt Drive for FXST
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