Trike City Scooters


Custom Installing our Scooter Trike Kit

If you are installing a trike conversion kit to a Linhai-Yamaha 260/300/400(VOG engine) Use the Linhai Installation button to the left.

Below will will install the trike kit to a Honda Forza 300, these procedures will be the same for all scooters other than the VOG.

Before you start installing the kit, read the entire instructions below at least once. The modications needed to mount the kit to the Forza were a little more involved than most other scooters we have done. So we decided to use it as the example.

Our first step is to align and center the scooter and rear axle assembly. We are using a motorcycle lift for our work space. You may be assembling on your garage floor. Put some narrow tape on your work space in a straight line about 2 feet longer than you scooter. The narrower the tape the better, 1/4 inch is great. Roll your scooter onto the tape placing both the the center of the front and rear tire on the center of the tape. This is extremely important, as you MUST get the rear axle assembly to a true right angle (90 degrees) of the bikes center line. If it is not a true right angle you will have shimmy in the steering; we call this wattle. We will discuss wattle later on.

In photo 1, to the right, the front and rear tires have been centered on our center line (your tape), and the rear axle assembly has been approximately centered to the line. The center stand is being used to support the scooter and engine. The front tire is locked down to touch the ground.

We are going to get a measurement of how far the rear tire is off the ground, ours about 1.5". You will now need the aluminum sprocket, if you don't have it yet you can use anything that is flat with a hole in the center large to take the place of a sprocket, for alignment only.

The rear tire has been removed and the aluminum sprocket has been placed onto the axle in place of the rear tire. The actual name for the axle is the output shaft. The sprocket hole is way to large for the output shaft, but we are using it to determine how we will setup the rear axle assembly. When you remove the caliper, do not disconnect it from the brake hose yet. In photo 1, above, we disconnected it and connected the new rear caliper. Bleeding brakes on scooters is a small project in itself. We used method 1 to bleed the caliper which is described later on.

The axle carrier has been bolted back on. The axle carrier is the black bracket on the right side of the scooter that the muffler is supported by and secures the right side of the axle. The rear axle assembly is now sitting on a 2 x 12 and a 3/8" shim under it to give us our height. If the axle assembly is too low the bike the back of the bike will be too high and it will plow into the turns. Remember that the scooter is on an angle with the rear pointing up. So we add a little to the height of the rear axle assemble.

Now we need to align the center of the rear axle assembly to the center line of the scooter. Then attempt to align the sprockets up in a straight line. If not, we need determine how out of alignment they are. The rear axle assembly can be moved right by as much as 1". The sprocket center hole can be enlarged to about 3"or more and a second spline plate can be added with a matching hole. Allowing the sprocket to run around the output shaft housing by as much as 7/16" as shown in photo 2 to the right. If this is not enough, as we have found on a Bergmann 650. We removed the differential and flipped it over. Putting the sprocket on the right side. This is accomplished by removing the wheel hubs and the retaining snap ring. Pull the axles out and flip. The caliper mount will need to be relocated.

We can machine the sprocket to except recessed cap bolts or completely flush bolts if needed.

The more the off center the rear axle carrier the more low speed wattle you will have. Bare in mind on any scooter there is some wattle on take off, as the scooter does not have the weight of a Harley Davidson. We recommend trying to kept the axle assembly no more than 1" off center. A left shift in body weight will compensate.

The next step will be the swing arm. Do not use torches to cut it, use a sawsall or hand saw, and grind. You do not want to put to much heat to the metal and soften it.

In photo 3 we have rough trimmed the swing arm of the kit to see what we want to keep. We make this decision based on how we will fabricate our attachment plates. Keeping in mind that we need the rear axle assembly is lower than the scooters rear axle; the tires on the kit are smaller than the scooters rear tire was. The height difference should be at least 1/2 the difference of the scooters rear tire height to the kits tire height. It can be greater but not less; less will cause the steering to plow in a turn. We also need to determine the angle to mount the attaching plates so that the chain rides over and under the tube on the rear axle assemble carrier.(shown in photo 4 below)
If you are using the aluminum sprocket you need to account for it sitting a little low as it is not centered yet. We have bolted the rear axle assembly carrier on and we have trimmed the axle assemble carrier to our desired starting point for this application. We will now design our mounting plates. They will be bolted to the scooter with at least two mounting points on each side.

We first made cardboard templates, then cut them out of 3/16" flat stock steel; you may also use 1/4".

Now would be a good time to view or CN250 mounting technic.This will give some ideas on what you need to accomplish.

In photo 4 above you will notice that there is no place for a second mounting bolt on the left side. The Forza was the only scooter we have done that did not have any place to put a second mounting bolt. So we welded a 1 x 1 x 2 piece of aluminum the the CVT cover at a place that was reinforced internally. You can see the black arrow where we will weld the block on to.

The next thing to remember as we make the mounting plates, the rear axle carrier must be exactly square to the scooter. To ensure that we will use the two bolts for measuring as shown with the red line in photo 4.

We will always use the shock mounting bolt for one of the two mounting bolts on each plate. With cardboard templates made we will rough cut our steel plates. And fit them to the scooter, drill our holes so that each hole hold its' bolt snug. We will only tach weld our plates to the carrier for now.

This is the left mounting plate we made for the Forza shown in photo 5 to the left. When drilling the mounting bolt hole is is important that you drill a precise hole. If the hole is too large the mounting bracket will move about. You will also notice that we have the bottom side of the bracket kissing the CVT cover to give it more support. We are spreading the load over a larger surface.

You will also notice the the shock adjustment tab was in our way so we cut the mounting plate around it. Our chain runs over and under the carrier bar. And welded the plate around the gussets of the carrier.

Photo 6 shows the right side mounting plate tack welded on. We used the shock mounting bolt for the rear mounting points and one of the scooters rear brake mount holes for the right front mounting point (not drilled yet). We had the same problem with the shock adjustment tab as well, so we needed to cut around one of the muffler mounting points. We used 1/4" steel for the right mounting because of the narrow space between the muffler mount and shock tab. We used a 3/16" plate for the left side.

Having the right mounting secure and tack welded; we bolted the left mounting plate to the shock bolt, then remeasured our two bolts as shown in photo 4. Once our measurements where exactly on, we lightly tack weld the left side to the carrier.

You will only have about 1/32" adjustment to square up the rear axle assembly using the chain adjusters. So only lightly tack weld. You want to make sure that after the right side is firmly mounted to the scooter's output shaft carrier you can still break the weld to move the rear axle assembly. You want it to be dead square now. The 1/32" may be needed to remove any wattle after test riding.

Once you are sure everything is square and secure you can weld the plates on securely. Now is the time to figure out exactly what sprocket assembly you will need. If you need help send us a photo before ordering your sprocket; and tell us what you are planning. You will need to remove the rear axle assemble to install the sprocket assembly.

Now we need to get your spline ready. The spline is the steel metal piece found in the center of your rear scooter wheel. If has the teeth that mate to the output shaft. You will need to move it from the rim. The spline is actual larger than what you see and made of cast iron. It is star shaped not round. It is normally has about 8 teeth making the star so that it does not slip in the rim.

You will need to remove this. Method 1, if you have an alloy wheel, is to use a 50 ton press and press it out; the rim will exploded so stand back. Method 2, place the rim in a vise, using a sawsall cut the rim make 4 or 5 cuts down toward the spline. Only cut to about 3/16" above the spline. You should now be able to break the rim apart leaving the spline intact.

You will now need to machine the spline round and mate the spline plate to the spline. We offer this service, see our ordering page.

Please click on this link now to read about installing the sprocket assembly.

Once the sprocket assembly is lined up we can take off the axle carrier and rear axle assembly. Weld up the spline plate and spline and reassemble the scooter. Be sure you have the correct size spacers between the spline and axle carrier. Fit the chain and adjust it, remember you can always get half links. Fit the chain to the most forward position possible so that you can adjust as the chain stretches.

Hook up the rear caliper, see bleeding the brakes section first.

Check the tire pressure and install the muffler and the fenders. If the right fender is interfering with the muffler you will need to add washers to the bracket as we did in the photo to the right. Or modify your muffler or fender brackets as we did here.

Now let test ride it, after our test ride (if we are a heavy person) the suspension maybe a too little soft, we can add a 3rd shock. A 3rd shock would need you to make a bracket at the top between the two shock mounts under the seat and one on the swing arm inline with the two existing shocks.

Now we need to fine tune the rear end alignment. There are two chain adjusting screws on the bottom back of the swing arm where the rear axle assembly bolts on. Have someone drive the scooter, starting off slow and on level ground. If the handle bars do not wattle when taking off you have done a great job. If it wattles you need to make adjustments. Now we can finish assembling any body parts we removed earlier.

Our finished trike

Wattle is the effect of one rear tire pulling more than the other; causing the front wheel to pull left than right shaking the handle bar back and forth. If the rear axle assembly is not a true right angle to the center line of the bike, one tire will be in front of the opposite side, even a fraction of an inch, causing a wattle. Upon completion of the installation you will be able to adjust the rear axle assemble by about 1/32 of an inch to fine tune the right angle using the chain tension adjusters. A 1/32" is a lot on a 3 wheel short wheel base. It is also to be noted that a small amount of wattle is to be expected at low speed, even if the axle assemble is a perfect 90 degrees to the center line. The differential will put the torgue to one wheel, more the the other on take off. The tire with the most torgue will push the bike forward on that side causing a slight low speed wattle.


Bleeding the Brakes

There are a few methods to bleed the brakes. In all case we suggest that you fill the caliper and hose up with Dot 3 brake fluid before connecting the brake hose to your hose. We do this by using a squirt oil can, the old metal oil cans with the pull lever and open the bleeder valve on the caliper. Be sure the master cylinder never runs out of brake fluid.

  1. With the rear axle assembly unbolted from the scooter, turn the assembly on its' side, on one wheel with the caliper closest to the ceiling. Open the bleeder valve and leave it open for awhile; vibrate the hose a little even now and then. After a short time you may see fluid dripping out of the bleeder valve. If not close the valve start to bleed the brake normal until some fluid come out of the valve. Then place the rear back in place.
  2. With the caliper disconnect from the scooter, disconnect the caliper from the axle assemble and reroute the hose over the top of the assembly. Hold the caliper up in the air as high as you can. Follow the instruction in method 1.
  3. Use a vacuum bleeder.

Now once you know that the caliper is full open the master cylinder, looking inside of it and very, very slowly squeeze the lever. once you see a air bubble emerge STOP. Do not pull the lever any farther, wait a few seconds and repeat the process until no more air emerges. Vibrate the brake hose and repeat the process. When on more air emerges use your vacuum pump or manual bleed the brake until you have a pedal.

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