3203 project

[x45guy]

I am working on a yd 3203. A neighbor threw out Yamaha atv tires and rims (4x110 pattern). The rears are 25x10x8 i believe. I have them mounted using hubs i saw link for on here ( 1 inch with keyway).

I am looking for ideas as how to reinforce or improve rear swingarm and suspension because the tires are big and heavy. Also should extra support bearing be added to axle or go with flex proof alone with no support?

I will run a 9t on jackshaft and not sure on axle sprocket-any recomendations?

the front tie rods are kind of spindly looking-any cheap upgrades here?


I will probably run the 14hp Clone motor.

Thanks

[x-bird]

the swingarm is pretty weak in stock form. The axle itself on the other hand is pretty stout--if it's straight, i'd keep it. . for the HP level your gong with and tire size, i'd consider adding a second tubing run all the way around the swingarm rectangle and adding an extra pair of bearing hangars. you'll want better shocks back there too.

once you start running it hard, especially if you put 14 hp to it, the entire front end is going to get beat to death pretty quickly. at this stage you might be better off moving into a 150cc buggy because you will be fixing the front end over and over or fabricating a whole new one from scratch.

[x45guy]

The axle is new. has anyone added another pair of bearing hangers to a 3203?
i will do a search and see if i can find a picture
thanks

[x-bird]

I don't recall anyone adding them to an 03, can't remember if there's enough room to do a set on the sides of the swingarm or just room for one around center to help avoid engine torque pulling on it too much. can you post some pics of yours with the new rims/tires on it?

[x45guy]

here it is. I am replacing the bar that was cut out. It had a suzuki 3 wheeler motor on it
that was trashed.

i iknow tires are facing the wrong way. i need another locking collar. Should i use sleeves or pvc to keep the axle centered?

ideas for beefing up swingarm and adding center bearing support welcome

[x-bird]

I would box in another set of bearing hangars on the outside--you have the room for that. I'd also run some vertical tube stubs from the frame down alongside the original hangars, then run a tube from the bottom of those on an angle to the front and rear corners of the swingarm frame. these are notorious for cracking just ahead of the original bearing hangars and also where the engine plate meets the rear frame. another area they break at is the front frame's tubing junction just above the rear shock mounts.

The original setup used snap rings on the axle to locate the bearings along with locking collars with bolts on the sprocket.

You may also want to consider installing a hyd. caliper/rotor setup on it and ditch the band brake.

[x45guy]

thanks X bird
Could you draw a quick diagram as to where to add tubing? and also suggestions for what disc brake combo to go with

[x-bird]

I knew the request for a diagram was coming--i don't have a program to really do one with. if i find the time i'll sketch a drawing, take a pic and post it. Initially i'd say pick up yerf spiderbox brake parts from BMI, but the caliper doesnt' have a parking brake lever, which is a nice feature to have. you could use another brand caliper as long as the brake line fitting is the same diameter and pitch. if you look through the build threads on the site you'll see a couple different varieties. toughest part is usually figuring out where to stick the caliper mount bracket. The 3203s cable and rod will get you from the pedal to the yerf master pretty easily--if you look at my yerf upgrade thread around page 3 or 4 you'll see how i did it--about the same setup is in the mini shark project i did. Rather than buy the mount bracket and pivot lever for the master, i cut and drilled my own.

[x-bird]

Here's a quick sketch of the idea. If you keep that swingarm, it will need help, (as will a lot of other areas if you go to 14 hp) so i hope you have access to a welder angle grinder etc....

The full shaded in lines are where i'd add tubing to beef things up--a rear view would show the added tubing continuing all the way around the perimeter of the swingarm. I went off memory and accidentally drew 3206 style hangars, so your front angle would be equal with the rear, not shallower as i've drawn it. If you look at the first page of "my yerf upgrade" thread, you'll see how i changed the swingarm pivots. that change moved the stresses to the frame and it ended up bending the main frame rear cross tube where it mounted. I'd beef that up as well. The first page also shows where these swingarms crack and bend at--with basically stock to 8-9 hp power levels.

As far as brakes go, you're best bet might be to add or have another keyway added to the axle and go with a keyed hub for the brake rotor.