2 speed stopped 2 speeding

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fstnd

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So I converted my factory single-speed smartech winner into a two-speed and it worked awesomely for 2 or 3 tanks. I made a thread about how I "converted" it btw.

Anyway after these 2 or 3 tanks my 2 speed stopped switching to second gear? You can hear on the video the first time, and it works, and the second time the 2 speed somehow kicks in but immediately kicks back into first speed and never got into second again... What went wrong?

 
So I converted my factory single-speed smartech winner into a two-speed and it worked awesomely for 2 or 3 tanks. I made a thread about how I "converted" it btw.

Anyway after these 2 or 3 tanks my 2 speed stopped switching to second gear? You can hear on the video the first time, and it works, and the second time the 2 speed somehow kicks in but immediately kicks back into first speed and never got into second again... What went wrong?


It looks like you used the HSP gearbox, (good choice imo, easy to maintain and parts are plentiful), they have a bit of an Achilles heel in the second speed gear where a hardened steel pin is pressed in to "receive" the claw that swings out to engage 2nd gear. What happens is the pin gets pulled out of the gear, and then the claw of the clutch chops through the plastic in a few shifts.

The good news is, you can fix it for good. You'll need a replacement gear, which comes without a pin pressed in (its own headache for people who don't know about the pin and wonder why their gears keep failing). You can use one of the hex pins, but here's the trick - hold it tightly in vice grips or pliers, and blowtorch the end red hot to anneal it. Then use a hammer and metal surface to hammer a "mushroom" head onto the softened end of the pin. Finally, press this into the replacement gear from the back, so that the flared end of the pin keeps it from getting pulled through the gear. With this fix, the gear will reliably last until something else breaks. I've even pulled my modified pin back out of a stripped gear and put it in the next one. I've done this mod for all of my 2-speeds.

Part of the trick is you can anneal one end without losing the hardening on the other end, held in the grips, since they'll absorb heat from it.
 
Last edited:
Thanks for the reply👍
Is this the pin that you are talking about? I shredded this part of the plastic quite well
20240512_143916.jpg
luckily I bought another gear as it's literally 53 cents lol. Is this where the pin is supposed to go?
20240512_143927.jpg


Anyway, I've never used a blowtorch before and actually don't have one, would it be a fix to just buy this gear but in metal form?
Screenshot_20240512_144325_AliExpress.jpg
 
Thanks for the reply👍
Is this the pin that you are talking about? I shredded this part of the plastic quite wellView attachment 189792luckily I bought another gear as it's literally 53 cents lol. Is this where the pin is supposed to go?View attachment 189794

Anyway, I've never used a blowtorch before and actually don't have one, would it be a fix to just buy this gear but in metal form?View attachment 189796

Yes to both, but be aware that said gear is solid steel and pretty heavy, just from a performance standpoint.

You could try glueing a hex pin in, you'd just need to grind it down to 8mm length. The issue is the sharp smack of the clutch engaging eventually wiggles it loose, so a solid gear would be one way to eliminate the issue.
 
Thanks I think I'll order the steel gear anyway, but I'll also try to use the gear I already got with something to serve as a pin👍 perhaps a grub screw with red loctite...
 
My try: instead of a pin, I used a screw and screwed it in while drowning in red loctite. Afterwards I "removed" the head of the screw. Sorry for not following your plan but I really don't have the equipment
20240512_201908.jpg
20240512_202601.jpg
 

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