Yokomo 870C aka.1988 YZ10 build with
White winter arms
2mm fine pitch drive train
Yokomo Hotlaps wheels
Lightened diff cups
Composite Craft shock towers
Front aluminum bulkhead
AE steel turnbuckles from RC10 Worlds re-release kit
SRS steering blocks
Hotdog4 built with
AE 870C shock towers
MX4 rear aluminum CVD bones
Academy molded wing
Extended wheelbase with longer rear belt
White Kydex bumper, homemade
870C shocks with later shock ends for Works arms
AE steel turnbuckles from RC10 Worlds re-release
Magnesium bulkheads
Hodog4 has the copper springs now
And, few more pics with C4 body
This post would be a help. but it seems impossible to get them unless you guys push MIP to make them again.
it’s the basic info for Yokomo CVD bones
’94 YZ10 front CVD bone 84mm
’94 YZ10 rear CVD bone 79mm
MX4 rear CVD bone 79mm
Kysho RB5/RB6 70mm CVD bones work for 870C F/R
MX4 rear bone works with ’94 YZ10 rear. and, Works F/R
’94 YZ10 rear bone works with Works F/R. and, for 870C front wide setup
Bj4 front bone doesn’t work for Yokomo diff cups
’94 YZ10 front
from the top, MX4 Rear / ’94 YZ10 Rear / Jconcpets BJ4 front.
the length are identical to each other. but the head pins are not. I’ve tried more CVD bones from AE and Losi. and all the US brand CVD bones have bigger head pins which don’t fit Yokomo diff cups
While the length is identical, Bj4 CVD bone don’t work for Yokomo diff cups
’94 yz10 cvd bones go deep inside of the diff
MX4 bones have longer head pins. it’s fine except for 870C
I started this build on my personal blogspot blog. then I moved whole the articles on slowbean. I might want to arrange them into one single thread later.
it’s my yokomo Hotdog4 built from YR4 kit with some Works bits, along with Yokomo Esprit stock motor. I’m working on the new shock towers.
MX4 rear CVD bones fits perfect for ’91 through ’93 Works. Hotdog4 has the same arms. and you guys can see the result. the length is same with post ’94 yz10 rear cvd bones.
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| YZ-834B SE Limited Edition |
Yokomo made this nice chain drive 4WD buggy at 1983 when Hirobo made 44B which was belt driven. YZ-834B was the 1st IFMAR winner at 1985. and we know who was the driver.
the 1st version came with flexable Kydex chassis and rear mono shock. also with front mono shock as you can see.
later chassis has a small bumper and batter chassis for race. but the material is still same. Kydex
RPS SE’s fiberglass chassis is very hard and tweak-proof. RPS SE came with lots of improved parts like shocks, gears, axles, and nice tires.
Delta and Trinity made the chassis as well. and this Trinity is still the best one to me.
[Updated]
Do not use the small black O-rings in the kit.
use metric O-rings which is hard type. not the soft ones like in AE shocks. the orange ones from later Yokomo shocks worked well.
Put black large cap seals. Yokomo ones are not helpful. AE shock cap O-rings works fine
Do not put the shock end till you finish the shock. you can adjust the rebound without the shock end
[Original Post]
The purple shocks look great and leak bad. and there are two different way to build these shocks.
The old way is with springs inside. and another method is with a thin washer instead of the spring. both hold the plastic bushing tight and prevent the leak. but the washer is more simple and works better to me. another problem with the spring method is the stroke keeps getting smaller while the oil leaks
It’s easy to exchange the spring to the washer. the later kit came with 10mm thin copper washer, and any thin washer with 9~10mm diameter works. but the inside hole should be 4mm or more. this margin makes the piston and the red large seal doing their jobs. and, don’t forget AE green slime
Sometimes we got broken shock shafts or alumium shock ends. or I want to use this non-leaking purple shock on my Hogdog4. later yokomo shock shafts are 3mm thick and they are too thin to be replaced. AE shock shafts work well with 870C shocks.
For this, you need to use the washer, not the spring. otherwise the shocks leak
With Composite Craft graphite shock towers and today’s work
The kingpins from 870C through YZ10 are basically same shoulder screws. even you can find the replacements from Tamiya and Kyosho as well. and MX4 kingpins are flanged bushing (flanged sleeve) which are easy to assemble and hard to be lost
The flanged sleeves should be assembled from inside to out on the front C hubs.
But, YZ10 C hub has a bit small room for MX4 kingpins. and both assembled from top to bottom. like these pics
All done with titanium screws, and ready to run.
Found some for myself and friends recently. I had a few while ago. but haven’t seen them for a while
There were 2 different ZD-304S from Yokomo. the early one is more simple, and later one came with idler bearings
the first one is here. it’s very unique with 4 of 4-40 SAE flathead screws on the bottom. they are the same screws you can find from AE cars. and I’m not sure with the later version. I haven’t opened the bag yet
And, this is the later one.
Someone posted some decent pictures of the 2nd version on Tamiya club.
http://www.tamiyaclub.com/showroom_model.asp?cid=121643&id=23290
Hudy seems to make the best setup tools on the market. but we never had one for Yokomo YZ10 5mm axle yet. or simply I didn’t see
I got this 1/8 on-road setup tool for 12mm axles. and only thing I need was 4 of 5x12mm bearings. I ordered the bearings. then forgot about it. some metric and SAE bearings came from Avid RC for my Yokomo and AE buggies. but couldn’t remember why I got 5x12mm bearings with them. it took a while to figure it out.
The setup tool is this. Hudy 1/8 on-road setup tool for 12mm axle. and I just switched the front and the rear ones.
Then 1/2″ step bit job on the other side for 3/16″ axles.
Then some thin paper tape to hold the bearings securely
Done
The tool works for the old 834B through YZ10, RC10, and modern 4WD as well.
On the rear axles, 5x12mm bearings works fine for 5mm and 3/16″ both. the difference is small. and we just need the camber angles on the rear axles.
Also, this tool is a very nice display stand for YZ10
There are two different versions
ZC-300AF Aluminum front bulkhead
ZC-300FC Aluminum front bulkhead for Works ’93
those two are basically same, except for the caster angle.
ZC-300FC for Works ’93 has bigger angle as you can see from the last picture
if the caster is same with the magnesium bulkhead, it’s 300AF. you can see that without the header.
Probably, I posted this somewhere. and I’m doing this again to remind my memory.
it’s the simple comparison
’94 / ’95 / ’97 YZ10 front > ’94~’97 YZ10 rear = Works ’91 / ’92 / ’93 Front = Works Rear = 870C front long version (with outer mount hole on the front arms) > 870C Front = 870C Rear
so, there are only 3 different lengths from Yokomo from ’87 through ’97.
but, there are more than one model number for the same length. it’s about the solidity.
870C universal drive, ZC-421 (front long version ZC-422) are softer than ZC-422A which is Works F/R universal drive. but ZC-422 and ZC-422A still have the same length.
there are ZC-423, ZC-423S, and ZD-423. all they are for ’94~’97 YZ10 front and the differences are solidity as well. it’s just about the material
Yokomo keeps testing and making new parts for their current and next models. it’s the reason they keep changing the model numbers and making newer ones. I respect that
From left to right,
ZD-423 = post ’94 YZ10 front, super hard version (same length with ZC-423, ZC423S)
ZD-422 = post ’94 YZ10 rear, super hard version (same with ZC-422A which is for Works)
ZC-422 = 870C front long version (same with ZD-422, and ZC-422A)
ZC-421 = 870C F/R
the actual length from the end to the other end is
107mm, 101mm, and 96mm
the length from the end to the universal joint is 25mm
my ’94 yz10 runner got a new shell with some decals today.
now it runs with
HD universal drives
Yokomo Aluminum motor mount
Team Suzuki F/R hubs and hub carriers
’93 WCS steering
[update from July 2nd, 2015]
found the MX4 wheel hubs for YZ10. and more MX4 wheels for this setup too.
pargu is working on the wheel hubs. you guys can use them pretty soon.
these 2 threads from rc10talk.com got lots of pics and information. i started this project from those as well
http://www.rc10talk.com/viewtopic.php?f=29&t=17274
http://www.rc10talk.com/viewtopic.php?f=29&t=15520
also this thread got lots of detailed pics
http://www.rc10talk.com/viewtopic.php?f=29&t=26696
my goal is building a ’93 WCS YZ10 replica with newer electronics and tiers for vintage race. i still need to get some correct parts for a replica. and, now i can run this before i get them. it’s a runner before a replica
I saw some 2.0″ imex disc wheels on ebay a while ago. the plain disc design was far from yoke Hotlaps aero wheels. but the structure itself looked pretty much same to me. it was 3 years ago
http://www.rc10talk.com/viewtopic.php?f=29&t=12708
then a close friend found me some imex wheels recently. so, i could build more 834B wheels from Hotlaps 2WD front wheels plus imex wheels today. it worked!
thank you so much Aaron!
and the leftovers..
center discs from imex and 2.2″ 2WD front outer rims from Hotlaps
and few more pics from my old posts
I grabbed this part lot off ebay. only what I need are the pulley bag. but the rest of them could be spare or could be a start for a new project.
the most important parts in this lot is this pulley bag. i used to have ZB-40 for rigid belt drive before. this ZB-40N is for the torque limiter setup.
NIB parts are getting hard to find everyday. I need more arms, c hubs, and steering knuckles always
new chain, very rare front oneway axles, rear dogbones, and steering linkage
I’v been keeping the important parts for my future.. and it’s the current project. I still remember the moment I saw YZ-834B at the first time. it was displayed in a show window of a shop which imported Sanyo batteries from Japan. the owner seemed to have a good taste RC cars. he picked up the 834b at Japan just because it looked cool
ok then, I bought a pair of Delta shock few years back. I had to sell most of my RC inventory for some reason. but I knew I would start this project.
found these AYK Race Prep dogbones and hardened front axles when I was running my 834b runners. later YZ-834B SE and RPS SE came with this hardened axle
[EDIT] I remember the dog bones were sold under Race Prep name. but the NIB package I saw on ebay was SRM RACING.
parts numbers are
SRM Racing Polybones 9300 Front / 9330 Rear
you can see this brand-new main chassis from this post
https://slowbean.net/2011/04/epoxy-chassis-for-834b/
but, I couldn’t find the chassis. I got moved into a new place a couple of years ago. I thought I put this chassis in a safe place, but it was too safe. haha!
so, I put the new parts on my old Trinity chassis like this
this project still have a issue with the torque limiter pulley, it’s really hard to find one. actually I’v been searched it before I left this hobby. but a good news is my friend Reggie got a pulley for solid setup. and it can be converted to torque limiter pulley. it’s not a problem. I won’t run this shelf queen.
then finally, I found the chassis in a box 2 weeks later. I got the chassis from Jason, my aussie friend few years ago. thanks Jason
after I moved the parts onto the chassis, I noticed I still needed the top deck, and my friend Gary sent me this nice one. Gary lives in OZ, but he found this from UK. even he looks cool!
but this project still nees front upper arms and steering knuckles. and my 2 different friends Al and Reggie found each arm between their parts. it was the most dramatic moment of this project.
And, here goes almost complete my 5th, maybe 6th YZ-834B Wonder Dog Fighter. it looks great with Delta shocks, Custom Works white wheels, Proline made RPS tires, non-stock but strong white steering from 870C through YZ10, and Checkpoint motor
my favorite wheels for 834B are definitely Hot Laps.
https://slowbean.net/2011/03/playing-with-hot-laps/
I have some front and rear wheels, but there was a matched pair. it looks not that good with white rim and red disc
another couple of days later, I managed to match the wheels. now it looks great even it doesn’t have the rear pulley. no one can’t see it’s not there though.
Al put these Hot Trick parts in the package with the front upper arms. thank you Sir!
more pics comming
to be continued..
ps. you might find some aluminum parts you need
http://www.pargustore.com/alloy-parts/yokomo/834b.html
I made this list from Asso_man!’s RC10talk thread a couple of years ago. and just noticed the file I uploaded has gone somwhere.
Yokomo YZ10 W.C.S part list thread on RC10talk
the scanned images are here
Yokomo YZ10 Pavidis Part list #1 & #2
I bought this MX-4 at the first day it came from the factory. I remember it was April maybe May ’98. and it’s still one of my favorites. actually I was faster with Losi XX4. but mostly raced with this MX-4. and I could learn more about race and setup from this beauty. everything is still fine except for the rear tires on the front wheel.
this trick is great for protecting the spur. the first batch came without this foam in the boxes. and they started to put this in the kits a couple of months later from the release
