2017.12.30, 11:48 PM
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#1
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Registered User
Join Date: Apr 2017
Posts: 48
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MA-020VE Steering Never Returns to Same Centre Position
I suspect a faulty servo saver, or poorly assembled servo saver. When steering left and returning to centre the centre position is more to the left. When steering right and returning to centre the steering position is more the right. It's been like this since new, never crashed (yet).
Any ideas?
Overall I'm pretty disappointed with the quality of assembly of my MA-020VE Pro SP. Bad solder joints, over tightened screws, screws threaded in off axis, wires crushed due to improper assembly, etc. The list keeps going.
Is this common with Mini-Zs nowadays? I bought mine out of HK from RC Mart, hope I didn't get a "hacked together" off the assembly line "counterfeit".
I have purchased (all new) 2 MR-01s, an MR-03, and an MA-020S and none have ever had such poor build quality, if fact, they have all been perfect. The MA-020VE Pro SP is the only one I purchased out of Hong Kong. The others from North America and Japan.
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2017.12.31, 11:52 AM
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#2
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Registered User
Join Date: Oct 2015
Posts: 35
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My servo issues on the mini-z pro's I own (2 x MR03 and 1 x MA02) had to do with either a stripped gear within the servo (get ready for some interesting surgery) or with a piece of tire rubber debris getting lodged within the servo gears (still have to take it apart).
I can definitely recommend the metal 4th gear upgrade for the servo. I have installed the metal one made by Kyosho and the aluminum one made by PN in my MR03's. I don't notice any difference between the two.
I've always had good luck with rc mart; same with tiny rc (associated with this site).
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2017.12.31, 08:14 PM
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#3
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epic procrastinator
Join Date: Jul 2006
Location: Whistler, B.C.
Posts: 2,216
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I've had this issue both with 010 and 020 and it directly related to an excess of material on the servo cover. The servo arm ever so slightly rubs so my suggestion is to dremel the inside of the cover a bit to give the servo a bit more room.
You might also check the tie rod throw for binding.... I've had that as well.
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2018.01.03, 11:56 AM
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#5
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02-Racer
Join Date: Sep 2004
Location: Belgium - Holsbeek
Posts: 949
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Thanks for the hints, I'm having similar issues on my MA-020 as well.
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2018.01.03, 12:25 PM
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#6
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Redline
Join Date: Aug 2012
Location: Greater Vancouver, B.C.
Posts: 218
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Another thing that has worked for me is not to totally tighten the four countersunk screws that hold the lower suspension arm/diff cover. Also adding a little bit of ruby lube to the tie rod helped too. The servo is a crazy tight fit in the AWD chassis and it can rub if things are even the tiniest bit out of alignment.
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2018.01.03, 04:23 PM
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#7
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Registered User
Join Date: Aug 2015
Posts: 80
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I had this issue too and trying to troubleshoot it drove me mad.
All the suggestions given are great, I tried them all and helped (metal 4th gear, check binding, dremel the top cover inside, leave the cover screws a little loose).
I would also add that there is quite a bit of natural play in the servo, so even a clean, free, lubed up servo assembly will probably always return to straight with a slight steer from where it came from (as you say, returning from left to straight leaves the wheels slightly turned to left). The car moving forward should straighten the wheels.
So if you check the return to neutral from a static car you will - I think- always notice a bit of this issue. It's when you feel the issue while driving that you really have a problem, and i had this many times.
Just the other day while doing a bit of cleaning up I noticed one of my cars steering binding and i found the reason was dirt on the the servo saver pin. Really frustrating as it's impossible to test how free these mechanisms are as you build them outside the chassis and then squeeze them back in and in that process, all sorts of little distortions can happen. External servos are so much easier to deal with!
Last edited by Minizorro; 2018.01.03 at 04:29 PM.
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2018.01.03, 07:05 PM
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#8
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Registered User
Join Date: Dec 2003
Location: VA -> MA + NH -> Now VA
Posts: 176
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A quick video I just recorded for you guys
https://youtu.be/BTg4L_CwAd8
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2018.01.03, 08:13 PM
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#9
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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Nice video, thanks for sharing
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2018.01.04, 12:17 AM
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#10
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Registered User
Join Date: Apr 2017
Posts: 48
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Thanks for all the input. Didn't know this was a problem that plagued the AWD chassis.
I took everything apart, reminds me of the MR-01 days, this chassis design is really dated. Did the even change the main chassis between the MA-01 and MA-020?
Turns out I found even more horrible QC issues inside. The front servo stay is broken where the screw goes through, and the piece isn't even inside the chassis. So it was assembled that way.
Same with the plastic bracket that holds the servo potentiometer in place, one of it's protruding "centering" legs is missing, that could explain the failure to return to centre correctly each time, but I doubt it as the bottom is flat, and that should keep the pot centred when all assembled.
Also, more horrible solder joints and the servo motor's ground wire has it's PVC sleeve ripped (probably from incorrect routing and have it crushed) leaving wire strands exposed, rather close to the main PCB...
Back to the issue at hand, no broken gears, servo cover not making contact with anything. I re-assembled the whole chassis whilst leaving out the main PCB and servo components. Problem still there. I tried loosing the lower tie rod cover (this seemed likely to be the problem as every screw was over tightened and most stripped). Problem still there.
I removed the front knuckles, re-tightened the lower tie rod cover. Problem gone.
Inspected the front knuckle area that sits in the tie rod, noticed there are some protruding mold marks. Looked inside the tie rod where the part of the knuckle sits, found some more plastic protruding mold marks.
Re-assembled everything (still without the servo components) and noticed the binding is actually occurring when the mold marks from both the knuckles and tie rods do NOT make contact. Leads me to believe the issue is simply in the design of how the knuckles connect to the tie rod in this chassis. I still don't know why Kyosho hasn't switched over to regular ball joints like 1/10 cars with the Mini-Z line.
I suspect the problem will be resolved once I polish the parts of the knuckles and tie rod that make contact. Don't know how I'm going to go about that yet, only have some coarse files and don't want to create excessive play or friction.
Has anyone successfully eliminated the problem from their AWD Mini-Z chassis without extreme measures? My MA-020 is all stock with OEM Kyosho parts.
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2018.01.04, 11:50 AM
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#11
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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The MA chassis has been redesigned with the FWD. Its is one and the same actually, just using FWD only. Kyosho Taiwan has essentially confirmed the AWD will be using this new design moving forward.
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2018.01.04, 12:57 PM
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#12
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02-Racer
Join Date: Sep 2004
Location: Belgium - Holsbeek
Posts: 949
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It must be called MA-030(F) for something :-)
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2018.01.04, 02:52 PM
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#13
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Registered User
Join Date: Apr 2017
Posts: 48
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Quote:
Originally Posted by arch2b
The MA chassis has been redesigned with the FWD. Its is one and the same actually, just using FWD only. Kyosho Taiwan has essentially confirmed the AWD will be using this new design moving forward.
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Link?
Though now that I look at the rear "diff housing" on the FWD chassis, it seems obvious.
Was just thinking to myself I chose the worst possible time to invest into an MA-020VE PRO SP and almost every single Kyosho hop up.
However, looking at the FWD chassis, looks like they're going to milk their parts line up like always, suspension and diff housings look identical. Should be able to just buy a few chassis parts and swap everything over.
Bottom pic of FWD chassis shows diff housing "humps", driveshaft passage, and MA-03 on bottom:
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2018.01.06, 06:44 AM
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#14
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02-Racer
Join Date: Sep 2004
Location: Belgium - Holsbeek
Posts: 949
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I posted this link in the MA03F topic, without realizing this actually is and AWD conversion of the MA03F:
https://ameblo.jp/guruguruminiz/entry-12340511220.html
Check the link for more images
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