How many of us have broken the tabs off those **&%&R@%@* Yuasa batteries that are the ONLY size that fit our bikes? (I have tried everything but a cutting torch to fit in a bigger one! Still trying!)

Well, I have, a couple of times now. That's why there are two mods for keeping them from breaking!

What about AFTER breaking one, but BEFORE reading the other 2 neat mods? Got it!! I couldn't stand a new $80 battery sitting around unusable. So... I figured out a way to insert a 1/4"x29 screw threaded bolt vs our kludgy lead coated steel ones. (stainless for me of course) You can't put a huge amount of torque on the finished product, but it WILL take more than I can do with a nut driver or screwdriver! I do hope everyone will NOT pay undue notice to the melted plastic on the battery case. I used a BIG soldering iron, and had a case of the shakes from the flu. Ah well, cosmetics aren't really my thing. (tho more than Darryl!)

First I found some different brass inserts for use to fix the broken terminal. The middle & right one is the one I used. The middle shows before the locking tab is pressed into the bottom position, and the right one shows the bottom view with that tab pressed down where it will lock the insert in.

I found a drawing of the battery components and found that if you drill right in the center (both ways) of the tab base (after all, it's gone now!) there is more than sufficient metal around it to put a decent sized hole in it without weakening it too much. I drilled a 5/16" (.3125") hole straight down to a depth of just under 1/2". Use a variable speed drill so you can go SLOWLY, as the lead grabs the bit and almost sucks it down! WAY too easy to drill too deep and cause a leak or weaken the post structure on the internal part of the case. The insert, which I got from McMaster-Carr ( is $12.85 for a pack of 25. Don't give in to the impulse of using wood inserts, as they also SCREW OUT when the bolt is tight!! That is NOT what we want!

They are originally made for use in plastics, but I already found several other uses for them, so the other 20 or so won't go to waste!! These are perfect as they measure .312" at the top (tight thumped in fit if the hole is drilled careful!), the bottom before expansion is .280, which, when a tools (like the punch shown) is used to push the brass locking plate to the bottom, is then expanded to .325" which holds nicely even before soldering around it.

Again, I hope you will forgive the shaky melting of the plastic, but the first picture shows the insert bottomed out in the hole, which is just short of 1/2" from the TOP of the remaining lead tab. The locking tab had been pressed down and a 1/4" bolt is in it. I could not turn it hard enough by hand to make the insert turn, so I think this will hold up well unless you are the type to have every bolt or nut squeak before you quit turning!

Yes it looks crude, but so do I, and I work fine!!

These photos show the insert and how to push the tab down with something like a punch AFTER it is inserted in the hole! Notice the difference in size at the bottom (knurled) end!

Once the insert was pressed down snugly and the locking tab pushed in place, I used a BIG soldering iron (yep, melts that plastic right out of the way, huh?) to heat the insert until I could press it down a little more, and then soldered in around it with thick, heavy solder. (radiator type is good). I kind of surrounded it and shaped it so it contacted and soldered to the insert as well. Brass is good for soldering. Just don't get everything so hot you melt the whole post structure! AND remember to do this in a well ventilated place, as any off gassing from the battery is hydrogen, which is VERY flammable (read explosive here).

Eureka!! Another usable battery!! Just remember that the original tab probably had a metric 6mm bolt (doesn't matter as there are no threads, I use stainless 1/4"x20 myself) and this will now take a 1/4"x20 American size bolt. (SAE)