Guideline for Steering Stem Installation
A step-by-step guide.
Have a bent steering stem? It's really rather easy to get one, if your curious. Just open your scoot up to full throttle, and then nail a curb or a wall or somesuch. :P After you've acquired your freshly bent steering stem (sometimes called a triple-clamp or triple-tree) we'll give you some pointers on fixing it. This article assumes that you have the knowledge to remove the body panels required to perform a steering stem repair, as well as the headset and forks. Most of the time it is not nesessary to disassemble everything in the headset, but the rear brake cable and throttle cable can limit the room that you have to easily slide the headset up over the stem. Sometimes this can wait until you loosen the bolts and drop the stem, then you can remove the handlebars and headset assembly. For better or worse, the job is a little bit different on eacy scooter. Hopefully, this article will give you some general knowledge and tips that will help during the repair.
You can click on any of the images in this guide to view the full-sized photo. Enjoy! It's assumed that you've already gotten the steering stem out of the scooter, and are ready to re-install it. The real pill in this whole matter, is keeping the ball bearings from bouncing all over the place when trying to put the parts back together! Read on for more info. :)
It's usually best that the bearing races are replaced when doing this job, but it is possible to salvage the old races if you're careful. See the stem on the left in the photo? It's got the inner race on it still. You can heat it up with a propane torch (the heat expands the race, and it will come off easier) and then very gently tap it off with a hammer and chisel. Hammer and chisel are NOT advisable tools to use in many jobs with a scoot, but in this instance, if you're careful, you can get away with it.
You'll be using a few fingerfulls of grease when doing this job. Just about any grease will do, but bearing and chassis grease is prefered. This is available from your local NAPA auto parts store in a little 16oz tub.
Grease makes this whole operation a little more tolerable. If you spread some grease on the bearing's inner race (keep it kinda thick) you can stick the ball bearings to the race, and they will stay put.
Once you've got the race good and greased up, get a little dab of grease on your finger, and then pick up one of the little steel ball bearings. The grease on your fingertip should cause the bearing to stick to it. This makes placing the bearings MUCH easeir!
Continue on around the race 'till you've got them all packed in. Be sure not to put too many bearings on the race, as it will cause the stem to fit incorrectly when you go to reinstall it. The bearings should all touch each other for the most part, and there should be no large gaps or bearings on top of one another.
If you want, you can try and see how you do placing two ball bearings at a time. :)
The steel ball bearings are easy to loose. Most manufacturers can provide you with extras that come packaged in a bag with plenty of extra ball bearings.
You can follow the same procedure for the upper stem bearing as well. Keep in mind, that in the photo you're looking at the outer race of the upper bearing. There's more detail on this in the next steps.
Here, you can see that the inner race of the top bearing is actually threaded, and can be screwed down to meet the outer race and the ball bearings once the steering stem is installed from the bottom. It's important to take a minute to double check and make sure that the inner race fits good on the rest of the bearing assembly. If there are too many or too few bearings at this point, it should be easy to tell when fitting the inner race to the rest of the assembly. If you can't tell now, you'll certainly be able to tell when you get the stem on and actually thread the inner race down onto the bearings.
Taking our focus away from the top bearing, and back to the bottom, you can see that there's old grease in the outer race of the bottom bearing. This can be easily cleaned out with a paper towel and a shot of brake cleaner.
Here is the cleaned up product. Next, you should apply grease to the outer race in a similar fasion as you did the inner race.
Greased up, and good to go!
Just take it nice and easy when installing your steering stem back into the frame. Try to keep from sharp movement and take care not to knock the stem into anything. Gently guide it up through the frame, and take care not to disturb the ball bearings in the top or bottom races.
Once your inner race touches the rest of the lower bearing, don't let the stem back down. The ball bearings can every easily fall out and cause you to have to tackle the task all over again.
Very carefully thread the inner race of the top bearing down upon the outer race and the steel balls. Giggling the stem very carefully and slightly will help the balls find their place in between the races. Pay special attention to the way the inner race/nut fits onto the stem. You basicly want the inner race to be on just snug enough so that there's no side to side play whatsoever in the stem, but the stem will still glide effortlessly back and forth. You should be able to turn the stem at the top with your fingers, and have very little resistance. There is a .MOV video file illustrating this at the end of this document.
Once you've got the inner race of the top bearing on, you can snug down the top nut. If you want to use a little dab of loctite on the threads, that is acceptable. Hold the inner race while tightening the top nut. Double check the resistance, making sure that the stem has nearly fluid motion when turning it, and you're done with the tricky part! I prefer to put the front forks back on, along with the wheel, and take the scooter for a quick test drive somewhere safe (in the cul-de-sac or unused parking lot). Make sure that the scooter's steering behaves normally, and that the bike does not tend to want to sway back and forth when accelerating and at higher speeds. If it DOES want to sway, that is a dead fast indication that the inner race and top nut are too tight.