Yokomo 870 runner

[ra272]

Hello, here is my 870C or YZ10 runner.

I bought it on ebay in poor shape but hopefully complete.





Some parts have been hand made, not bad, but not my taste.



To be continued...

[ra272]

Complete disassembly.



First thing I've done is degreasing the magnesium bulkheads and remove oxydation with a glass bead blaster.



Then cleaning the plastic bulkhead caps...very tricky as the Yokomo plastic is not very resistant to solvent.
Beginning with the front cap I carefully remove the black paint with Acetone.



Then I remove the remaining paint with a Dremel and soft rubber abrasive point and wheels...very time consuming, but very nice result.

[jwscab]

nice job, those bulkhead caps are a nightmare.

I would spray some clear coat or apply some kind of wax or oil on the magnesium parts to keep them from oxidizing too quickly.

that's a really nice complete example and will restore very well.

based on the pink wheels and shock parts, that's an earlier release, not US, as I think the US model had white wheels and the shocks had an updated build method(remove those springs). Although I thought the shocks used rubber mounts on the first version, vs the white shock bushings.

[DennisM]

Great job so far

[ra272]

Thanks.

Cleaned bulkheads and caps, the hole in the rear cap has been filled with some dental resin.



The two front shock shaft were broken, I made some replacement with used Associated shaft.



I first tried the standard set up for the shocks but they were terrible as the big silicon O-ring won't stay in place. The result was odd rebound, leaks, and unstable length...



I've tried the "Associated" set up, adding a washer and replacing the spring by a small O-ring, but the O-rings were too much compressed, and there was too much drag on the shaft.

Best I've had so far is using a thin 9.5mm washer to keep the big O-ring in place and a 9mm O-ring on the lower cap to seal the damper body correctly.

I halso drilled bigger 1.6mm holes in the pistons in order to use thicker modern oils (30W seems to be the sweet spot).



The shocks are now working properly with very little to no leaks.
I've choose to use Associated spring collars as the have the little lip that hold the spring in place and avoid excessive rubbing on the anodization.

[Bormac]

Nice start to what will be a very cool buggy

[ra272]

Thanks, the buggy is now finished, here are some pictures of the rebuild.

I made a clone of the rear shock tower.



test fit of the cleaned parts and "new" rear tower.



Diff rebuild.



The fronts universals are totally worn out, I modified a pair of Losi 22 CVD not a perfect fit but they were cheap and the length is ok.







Stay tuned for the next episode.

[DennisM]

I like it!
Are You going to do a new body for it?

[jwscab]

Nice job on the cvds I figured they would be close. Are they 22-4 fronts?

[Bormac]

Brilliant job on making this car the best it can be with what you have.

[Sticksnpuck]

Wow! Great job on the cleaning and rebuild on this car. You have definitely given me some good tips on my own rebuilds that I will be doing this winter. Thanks!

[ra272]

Nice job on the cvds I figured they would be close. Are they 22-4 fronts?

They are 2wd Losi 22 rear cvd, I also had to grind 0.2mm on the pin diametre to make them work with the yokomo diff outdrives.

Lot of work on the wheels as they have been painted in black and in yellow..



I choose the cheapest option for 2.0 tires: the Tamiya Egress rerelease "super grippers".



Front end finished with a new Tough racing belt

[ra272]

Last pictures of the restoration.

I used an Associated body support to make a smaller battery post.



Electro is working fine: Reedy 19x4, Novak 610, KoPropo PS201 servo.



LiPo holder in 2.5mm FRP





Body and undertray are from penguin rc, not the best repro (warped) but fitting is ok.



The front bumper is home made from 2.5mm Kydex.

[therigliveson]

Looks fantastic!

[jwscab]

very very very nice!!!!