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Front fork replacement after accident

Posted: Wed Sep 04, 2019 3:22 pm
by afeinstein
I picked up a 2009 Buddy 150 from a salvage auction. Upon removing the totally bent up front fork (shocks were bent and the horizontal bar got broken bolts), I was surprised that dozens of ball bearings all fell out! Now I sourced a new front fork assembly and am putting it back together. Has anyone worked with the crazy ball bearings on these scooters?

It seems that the way the bearings go is that they are not part of a circle in which all the balls are totally connected and stay in place but rely on the stickiness of the grease to keep them in place long enough to insert the fork. Is this normal for scooters? All of the parts diagrams show the bearings in the connected circle form not loose?

I figured out that the the bearings are 1/4 in at the bottom and 3/16 at the top and I can buy them in bulk. Now the question is how many to use? I have learned that on bicycles they will leave enough space for 2 or 3 bearings. Am I on the right track?

Also, the new fork will not go nicely up through the frame tube. I am needing to give it a lot of force to go through. Does this mean that my frame fork tube is bent and I should forget about this whole repair?

Thanks.

Posted: Wed Sep 04, 2019 4:49 pm
by Stanza
That's fairly typical in the two wheel world, caged bearings (where it's all contained by a ring) are a luxury. You're right on with your theory, it's the application of sticky grease that holds the ball bearings in place for a while, and you install the triple tree before they can drop out. If your grease is decent, they should stay for a long while.

As for the quantity, it should be 3/16ths up top, 22x, and 1/4" on the bottom, 19x.

Posted: Wed Sep 04, 2019 7:59 pm
by buzzvert
I faced this exact scenario on a salvage Piaggio. The forks should go in easily and not bind, when the ignition assembly is removed. I'd definitely remove that as the impact could have bent or damaged the fork lock and is creating the friction point.

If, after the fork lock and ignition is out, the fork tube is still binding, I would suspect bent frame. That's what happened to me and I ended up getting another salvage bike with a good frame and marrying the two into a workable finished product.

Posted: Fri Sep 06, 2019 2:34 am
by afeinstein
Thanks so much to buzzvert and Stanza! Your advice was just what I needed and a true lifesaver. Thanks again!

I bought the bearings and having the exact count and sizes made it possible!!

And as for the fork not fitting, oh boy I made a dumb mistake. Turns out that one of the bearings fell down the steering fork column and thanks to the grease got stuck on the side wall. That's why the fork did not easily slip through! Once I ran a long wrench extension skimming around the walls, the little bearing dropped out and the fork fit just perfectly.

Now my next challenge is why the $100 lithium ion MMG battery that came with the bike won't hold a charge. It will charge to 13.5v and then in a few hours will drop down to 7v with nothing drawing any current from it. The bike only sat for 2 months and the battery looks pretty new. Maybe the force of the accident messed up the electronics in the battery? I will probably just buy a $20 sealed AGM battery from eBay.

Posted: Fri Sep 06, 2019 12:59 pm
by Stanza
Glad to hear it!

The lithium batteries are sometimes twitchy. Unlike lead acid batteries, Lithium cannot be deep-discharged safely. Pull voltage down to a certain level, and the cells swell and explode. So to keep everything happy, they have internal circuitry and a battery management system that regulates the power. I mention this because if that took damage, it may be dumping power internally.

You can test this by fully charging the battery, and taking it out of the bike to sit on its own. If it still loses charge with nothing connected, then the battery is roasted. If not, then you may have a short in the bike which is pulling power even if nothing is turned on.

Posted: Sun Sep 08, 2019 3:56 pm
by afeinstein
Yes. That's exactly what's happening. When off the bike and no load, it dumps from 13.5v to low 7 in a short time.
Any point in opening it up and looking for a bad connection or something fixable?

Posted: Sun Sep 08, 2019 10:44 pm
by sc00ter
I bet someone used a charger for a AMG battery on the lith-ion battery. Wal-Fart sells a nice AMG battery that fits the Buddy, and their warranty is very easy to deal with if something happens. I recently pulled forks off a junk Buddy for a friend and all the little bearings went everywhere. Im used to caged bearings.