Kona Stinky Restore

Joined
Sep 8, 2019
Messages
519
Location
USA, CA, Bay Area
Picked this up for $500:

2022-10-29 16.44.50.jpg

Based on that bazillions of forums threads I've read around here this is an older, but was well regarded setup. What I got here definitely needs some work, but it'll be my first middrive (I've wanted to do one for a while) and should be fun.

Came with, what appears to be, some variant of the GNG motor from about a decade ago. A 12AH 36v battery in decent shape. Battery was missing the charger and the key was lost. And, here's what got me excited, someone fit a Nuvinci 360 in the rear wheel.

It's got some broken spokes, is missing a drive chain, the controller was melting the phase wires, and it's generally pretty dirty. Otherwise, appears to be in decent shape!

So, gonna pull some spokes off to measure and order a few replacements, move the battery into the frame, replace the controller with one I've got around that comes with a screen, bleed the front brake which is very weak right now.

Based on this exceptionally long thread about the GNG I'm not _entirely_ sure how long it'll hold up and, if it fails, wether I want to put any effort into restoring it or just replacing it with something more modern (BBSHD, Cyclone, etc).
 
Excellent base for an easy-riding stable, comfortable urban vehicle, especially if your roads are in poor condition. Not always do you find a FS bike with large space in the triangle. :thumb:

NOT saying this is an issue in your case, but in my area, if an ebike is listed for sale missing the charger and key, and at low price, it is stolen 99% of the time.
 
99t4 said:
NOT saying this is an issue in your case, but in my area, if an ebike is listed for sale missing the charger and key, and at low price, it is stolen 99% of the time.

I was definitely suspicious; but I met the guy at his house and the state of the bike (obscene amount of bug/spider sign) I believed his "in storage for a year" story.
 
Been doing some reading and found a note in the original owners manual that, despite being a "single speed" drive, you must use a 3/32" chain because of clearances. Oops, had already ordered a 1/8" chain. Gave it a shot anyway and... it fits perfectly well. No clearance issues I can find at all.

I'm also trying to relocate that battery to the main triangle, but not having any real luck. There is space, but there's not enough space to allow for the insert/remove operation. Might just find a triangle bag and toss it in there for now, I just really don't want it on a post mount stem.

2022-10-31 14.12.29.jpg

Bummer.
 
chuyskywalker said:
Been doing some reading and found a note in the original owners manual that, despite being a "single speed" drive, you must use a 3/32" chain because of clearances. Oops, had already ordered a 1/8" chain. Gave it a shot anyway and... it fits perfectly well. No clearance issues I can find at all.

I'm also trying to relocate that battery to the main triangle, but not having any real luck. There is space, but there's not enough space to allow for the insert/remove operation. Might just find a triangle bag and toss it in there for now, I just really don't want it on a post mount stem.

2022-10-31 14.12.29.jpg

Bummer.

How does it fit upside down, under the top tube? You could attach it with wide Velcro straps, and still have it within the triangle. Might be a tight fit. Depending on what's inside the case, you could shave off part of the hump and epoxy in a flat piece of plastic for more clearance with the shock.

If you skip the mount, and contour the front lip of the case to match the bottom side of your top tube, it might give you a little more clearance and hug the frame better.
dolpin.jpg
 
If I can't retain the convenient "unlock, slide, remove" cycle I'll probably just resort to a custom made perma mount setup instead. A different case will, I think, fit more nicely. (The DP-5 case, specifically. I have the DP-6 from another build and it's just as close to fitting, just a smidge too tall to make slide on/off possible. The DP-5 is about 15mm shorter which should make up the difference.)
 
If that's the 19" frame, then possibly the EM3EV triangle

14S6P_Triangle_Hardcase-1.jpg
 
E-HP said:
If that's the 19" frame, then possibly the EM3EV triangle

Quite possibly; I have no idea which frame this is, but the "usable space" inside the frame is about 14" x 10" x 16" which seems just about the right size for that battery to fit, but might get real cozy with the bag adding some padding.

I'll keep it in mind, thanks for the pointer.
 
New spokes came in; been slowing getting that sorted out. Had to buy a spoke wrench beyond my "3 piece" set as these seem to be some rather large spoke nipples. c'est la vie, I'll get that tightened up and trued in the next few days.

Been hard at work on the battery situation. I waffled a lot between a 52v and 72v setup, but I've gone in on a 52v setup for now. Mostly it boiled down to the motor being previously run at 36v and not wanting to over stress it, but also there are some more modern mid-drives I may want to swap in at some point at the general high mark (without going into a lot of extra work) tends to have converged around 52v. (I have a configuration that could fit 80cells + bms in the triangle for a 20s4p if I ever go that route).

My 3d print + cnc combo makes for a lot of fun custom building. I modeled up an enclosure to fit the space, printed the sides, and then CNC'ed outer plates and inner cell holders to fit everything.

2022-11-07 21_07_49-Window.png

The layout is a bit windy/weird because of the space, but I can span most of the series connections with a few extra nickel strips and shouldn't have any issue hitting the 5/6 connections to peak at 50A:

52v-layout.png
topside.png
backside.png

Got to printing/cnc'ing and assembling (heat inserts with 3d prints are awesome):

2022-11-04 15.16.51.jpg2022-11-04 16.02.50.jpg2022-11-07 17.37.37.jpg2022-11-07 17.37.57.jpg2022-11-07 20.54.50.jpg2022-11-07 20.56.41.jpg

Haven't tried fitting in a BMS yet; but a small 14s 50A shouldn't be a hard fit. Daly's are pretty small up to 60A.

(Also, for the keen eye'd -- yeah, there are gaps between the sidewalls. I guess the prints had some shrinkage. I'll probably end up trying to fill those with epoxy or something.)
 
chuyskywalker said:
Haven't tried fitting in a BMS yet; but a small 14s 50A shouldn't be a hard fit. Daly's are pretty small up to 60A.
2.5 x 3.1 x 0.6 inches
https://srikobatteries.com/product/daly-bms-14s-48v-lithium-ion-50a-common-port-battery-protection-module/

Just guessing at the scale but it looks like it could be a wee bit tight.
Wee Bit Tight (inches).jpg

Note: He shows the same dimensions for the "DALY BMS 16S 48V 30A LiFePo4 " and I measure it to be 2.5 x 3.1 x 0.45 inches

Update (9 Nov 2022): Fixed scale of sketch
 
I've bought from Sriko a few times; nice to have a US based shipper, but some of their info is of....dubious validity. The AX page for the bms lists it at 80x16.

2022-11-08 10_59_26-Window.png

You're not wrong that it'll be a tight fit (and maybe not fit at all when reality comes to play!) There's other options I might consider if I hit that wall, but that gets pricier than I should spend on this build. (Neptune and Ennoid come to mind)

I tried a lot of different battery layouts/fits and while I could find a lot of other fitments (like using more of the corners, etc) the layouts always ended up with crappy group connections where I'd have to layer, like, 7 nickel strips across a single bridge point or something. (And I don't feel like doing copper/nickel for this build.)
 
chuyskywalker said:
... but some of their info is of....dubious validity.
True, however: 61 mm = 2.40 inches, 80 mm = 3.14 inches, 16 mm = 0.63 inches

edit: I updated my sketch above to reflect the scale shown in your last image. Still a tight fit but doable.
 
2022-11-12 19.20.10.jpg

Should work juuuust fine. Will drill out some spots on the cell holder to allow for pass through, and the balance leads will have a tight turn to take, but should be fine. Slap a piece of double sided tape in there and maybe a few pieces of foam just for good measure.
 
Been staring at this layout and just wasn't super happy with it so I took it back to the board and kept cracking away at it a bit. Found what I think is better:

1) Fewer "weak" series connections*
2) Actually has more free internal space
3) Can use a lot more pre-made ladder nickel cut strip (significantly easier than custom cutting every piece)

(*) I do recognize that, compared to the other layout, the weak connection spots are MUCH weaker, but I can pretty easily layer nickel to keep those in check.

general-bms.png
front.png
back.png
 
Battery all welded up, BMS leads soldered, on it's way to case time!

2022-11-15 22.19.50.jpg

I really like how the balance leads worked out on this one. :D Like a bunch of little worms, lol. Burnt the snot out of a finger when I screwed up and made a 6p group and then shorted it real nicely on the subsequent group. Whoops.

Going to get some padding put on so it'll squeeze nicely between the side panels, drill a hole for the power leads into the case, and I should be able to get it on the bike tomorrow, I think. Alas, it didn't quite fit right; you have to remove the shock to get the case in/out.
 
Rolling!

Some beauty shots:

2022-11-16 15.28.09.jpg

2022-11-16 15.28.44.jpg

At full throttle, I get 10mph / 20mph at the low vs. high gearing. I suspect this should be a bit more and that the Nuvinci needs to be calibrated... reset... something like that (I'm still learning about how it works, quite a bit more complicated than the regular 'ol derailuer).

I've got the phase current setup somewhat conservatively at the moment topping out at 30A, but could easily push the 75100 controller to double that, I'm just not sure what the motor can handle. I also need to charge the pack fully and let it balance for...a good long while, I didn't balance all the cells perfectly while building.

On the first ride around the block the chain tensioner worked it's way loose and bent the bolt; whoops :D Glad I didn't go too far, I walked it back.

Also want to replace the throttle; it's a hot mess in the weird position it's at (it's a thumb throttle for the right side, mounted leftside, so it's upside down and you have to use your index to kind hold it. Yuck city.)

And the front brake needs a bleed really badly; no brake engagement until pulling the lever almost completely down.

So; just a few things to sort out. Maybe a cover for the belt on the left side.
 
Changed up quite a bit since last post:

2023-01-28 15.44.57.jpg

Swapped out the mid-drive of unknown origin. It was running really rough, misalign, and I just wasn't digging it.

Along with the mid-drive swap out, I picked up a MXUS 3k 3t wind for a pretty low price to build into a new wheel. This of course put the nuvinci on the sidelines. Maybe I'll come back to mid-drive at some point, but...

As has been documented other places, the 3k just doesn't have enough room on the caliper side to actually support hydraulic brakes, sadly. But that's not a huge issue as I swapped out the throttle for a mid-reset twist throttle so I have proportional regen on the back, which is enough

I also swapped out the controller for a Makerx G300 which can push WAY more amps than this battery configuration can handle. I spent a LOT of time 3d printing mounts and trying to figure out where to put it...till I tried on a lark and found it still fits in the same under-seat bag, lol.

2023-01-28 15.45.31.jpg

Other miscellaneous items like new tires, tubes, and bleeding/tuning up the front brake have all been handled too. Gonna button up a few items (like that voltage divider just hanging around in the picture above) and get some fenders on it -- then time to hit a trail and see how this goes.
 
chuyskywalker said:
As has been documented other places, the 3k just doesn't have enough room on the caliper side to actually support hydraulic brakes, sadly.
Even with the large rotor?
 
99t4 said:
chuyskywalker said:
As has been documented other places, the 3k just doesn't have enough room on the caliper side to actually support hydraulic brakes, sadly.
Even with the large rotor?

I've yet to find a 400mm rotor ;D

Yeah, even all the way up to the 203, probably even the 220. Basically the entire diameter of the motor shell on that side is flat and the same disc-distance away.

What's worse is that, because this is also the cable exit side, you can't push the disc out further with spacers because the heads of the bolts would start to chew up the cord.

The only solution I've seen theorized, but never seen in reality, is something like the "floating disc rotor"s, but with offsetting bolts. Like...

https://a360.co/3kUrdal

Huh, it seems this is a thing for motorcycles, though.
 
Here's the problem:

2023-01-30 10.50.21.jpg

<14mm of space for the back half of the caliper is just too small. You need at least 18mm to fit most, so this is way too small.

So I spent some more time on that model and came up with something I think might work.

2023-01-30 17_53_09-Window.png

A mock up of all the elements. Found a model of the MXUS on grabcad; modified it to fit the proper dimensions (I think it was a 5k which has more space). Added a caliper and such to ensure the second set of bolts don't interfere. This should create a nice little "pocket" of space for the motor wire, and also push the rotor out far enough to get a proper caliper on there.

2023-01-30 17_53_51-Window.png

The minimal stackup adds 3.7mm of depth, so... 13.7+3.7 = 17.4mm of space.

2023-01-30 17_54_22-Window.png

A 3d print of the mockup seems to bear out, so I went ahead and ordered these up over at sendcutsend in stainless. (Picked up two spacers just in case I want more depth). Will see how it goes.
 
chuyskywalker said:
...and also push the rotor out far enough to get a proper caliper on there.
Don't forget to check dished rotor to seat stay clearance.
 
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