Turbo Optima Re-Re Transmission

[sundevil67]

Am I crazy or is this exploded view different from my manual, in that there's TWO OT225b spacers instead of the ONE ??!

This is a complex slipper assembly so maybe it will help to look at an exploded view.

Kyosho Turbo Optima slipper assembly.jpg

[GoMachV]

the other spacer is installed inside the trans case in a previous step along with the gear, so it would not be shown in that step. You must have both spacers!

[sundevil67]

Right; I see, from step #4... I haven't tore open the gear boxes, but would the diffs & belt drive able to rotate/move smoothly by hand or rolling if I'd forgotten that spacer somehow? It'd also be in my 'extra' bin...and I don't think I lost it. Crap. I thought I had a possibility there. It does sound like a slipper clutch issue, but tightening it all the way doesn't help. Should that spring be rotating in the opposite direction of the wheels? I did have to reverse channel 2 to get FWRD/REV correct from the transmitter... Video Test Here

the other spacer is installed inside the trans case in a previous step along with the gear, so it would not be shown in that step. You must have both spacers!

[GoMachV]

The spacer only comes into play when you tighten the slipper, which is exactly what you are describing. The drivetrain would be free with or without that spacer so long as the slipper is left very loose. When tightened, since there would be no spacer, it would bind up

[XLR8]

Yes, the entire slipper clutch/gear/shaft/spring assembly rotates opposite the direction of the wheels.
Unfortunately, it appears that you've missed installing one of those OT225b spacers when you assembled the slipper shaft assembly and this is why you're not able to tighten the slipper sufficiently to drive the car.
I'm also curious about that stray ball bearing ball found in the gear cover. One of the bearings might have come apart. You'll find it when you pull the gearbox apart.

[sundevil67]

Absolutely brutal...I can't see how I could have forgotten that spacer AND lost it - but it looks like there's no way around tearing the gear boxes apart. Hopefully I'll find whatever it is in the rear. I just hate that I have to pretty much go back to step 3 & rebuild the whole thing over again. There were a few spots that I don't see how I'll ever get it back together without 3 smaller extra fingers. I don't know how I did this in a weekend when I was 14, but the same job has taken over a year now. Thanks for all of the help... Hopefully I'll have an update sooner than another year.

[Coelacanth]

but it looks like there's no way around tearing the gear boxes apart. Hopefully I'll find whatever it is in the rear. I just hate that I have to pretty much go back to step 3 & rebuild the whole thing over again.

Ahh yes, one of the annoyances of the Optima design...I've had to do the same thing a time or two with my original Zebra Optima car, when I originally built it and decades later when I completely restored it, both times because I had the chain installed with the links leading edges oriented the wrong way... It was a common mistake if the builder wasn't looking very closely at the manual.

[TheDiamondOne]

I just built one, and would be happy to fix it for you if you would like to ship it to me.

[sundevil67]

I've already torn most of it apart...so I guess I may as well keep going. Though now I'm really struggling to keep the OT202 thingies from moving so I can remove the long screws... can't even apply enough force with the needle nose to keep it steady. There might also be some thread-lock in there gumming things up.

Worst. Build. Ever. I don't think I'll ever get the rear stabilizer bar on there either with that tiny nut either. If I can manage to get it apart & can't find anything wrong in the rear gearbox, I will cobble back together whatever I can & ship it off if I don't smash it into pieces out of rage before then.

[Coelacanth]

Worst. Build. Ever. I don't think I'll ever get the rear stabilizer bar on there either with that tiny nut either. If I can manage to get it apart & can't find anything wrong in the rear gearbox, I will cobble back together whatever I can & ship it off if I don't smash it into pieces out of rage before then.

Aren't those tiny nuts captured inside plastic hex holes in the mounting pieces? I never had problems assembling the rear stabilizers. Press the nuts inside the plastic mounts and install the screws.

https://www.youtube.com/watch?v=i0bxA_C_tkA


I'm also not understanding the difficulty with removing the long gearbox screws. Those OT202's are nothing but spacers from the looks of it. Won't the screws simply pull straight out once they're unscrewed out of the opposite gearbox side-plate? The original design had these spacers molded into the gearbox shape itself, the only threaded part is in the opposite gearbox plate.

[GoMachV]

Yup the screws come right out, the most I’ve ever had to do was to use a paper clip through the motor plate holes to push the screws a little so I could grab em. The spacers are not threaded so there should be no need to hold them with pliers at all

[TheDiamondOne]

Not laughing at you, but laughing alot reading this thread.

[sundevil67]

I did manage to pull apart the rear gearbox, and just like I feared, it's all correct, spacer & all.

This part would just spin when unscrewing from the outside...I did finally manage to get it off of there; maybe those spacers are stripped after having to be removed & reinstalled so many times.

[GoMachV]

the spacers have through holes, they are not threaded. If they are somehow threaded, its from thread lock getting in there. Push a screw through each one back and forth several times and clean out any goo

[XLR8]

I did manage to pull apart the rear gearbox, and just like I feared, it's all correct, spacer & all.

Wow, this is a serious head-scratcher.
Now that it's apart, maybe you could assemble the entire slipper assembly outside the car (from plates to nut - the whole thing) and confirm that you can tighten the nut against the spring sufficiently to lock the big gear so that it can't spin on the shaft?
If the slipper assembly is working correctly, it should not be easy to spin the big gear with one hand while holding the small gear with the other after the nut is tightened.