my Stealth b52 V-Boxx FR9 is crap.

[coinops]

I bought a used 2018 Stealth B52 with 400 kilometers and i wish it didn't have the 9-speed V-Boxx.
While pedaling and shifting through each gear there is always a horrible crunching noise from the V-Boxx and the shifter mechanism on the left side of the handle bar is poorly designed and not engaging each gear correctly with the V-boxx
I might just have to use this bike for the motor drive system while riding and not use the pedal system at all.

 

[coinops]

And it gets worse,
I want to remove the v-boxx from my bike and open it up but neither Stealth or the v-box manufacturer has made available a service/repair manual for it.
That's straight up ridiculous, i'm sure Stealth wants there customer to be totally ignorant about there bike and parts.

 

[neptronix]

This is a pretty typical experience with a proprietary system, and with a good % of prebuilt bikes.

We strongly encourage building your own bike here and avoiding exotic drivetrains or parts you'll never find replacements for whenever possible.
But people usually end up here after they've made those kind of mistakes.

Welcome to the forum

 

[coinops]

This is a pretty typical experience with a proprietary system, and with a good % of prebuilt bikes.

We strongly encourage building your own bike here and avoiding exotic drivetrains or parts you'll never find replacements for whenever possible.
But people usually end up here after they've made those kind of mistakes.

Welcome to the forum

Hey thanks for the welcome.
I'm glad i didn't buy it new as i paid about 45% of the new price.
the battery appears to be in good condition so is the hub motor as well.
i rode it yesterday and i might ride it again tomorrow if the weather is o.k.

 

[coinops]

i thought to add some photos.

 

[AdR]

Why would an electric motorcycle need pedals. Hmmmm. Just remove the chain and ride it like the motorcycle that it is

 

[coinops]

Why would an electric motorcycle need pedals. Hmmmm. Just remove the chain and ride it like the motorcycle that it is

Stealth bikes has the same opinion.

 

[glennb]

Yeah, no proper service manual. Best bet's probably this thread:

Dlogic´s V-Boxx Clinic

The Vboxx Clinic Hi members, just yesterday my Suntour V-Boxx broke down on me in the middle of a ride. When shifting down from the ninth to the eigth gear it just kept popping out. The same occured with gears number 3 and 6. A weird clicking noise could be heard when pedaling. Once home i...

endless-sphere.com

It's a decent looking gearbox. Might be finicky to get right, but it should perform well when tuned

 

[coinops]

Yeah, no proper service manual. Best bet's probably this thread:

I can't shift the gears up or down without it crunching and i'll remove the unit and open it sometime to have a closer look.

 

[coinops]

Google AI Overview.

The Suntour V-Boxx FR9 (a 9-speed internal gearbox often found on high-powered e-bikes like the Stealth Bomber) is generally durable but susceptible to specific mechanical and maintenance issues. Common problems include gear slipping under load, internal wear from a lack of grease, and shifting cable tension issues. [1, 2, 3]

Common Problems and Fixes

• Gears Slipping/Popping Out: Often reported in gears 3, 6, and 9. This usually occurs when the shift cables stretch out or are misadjusted, preventing the internal mechanism from fully locking into gear.
  • Fix: Check and adjust the cable tension using the barrel adjusters. In severe cases, the internal shifting cassette or pawls may be worn and require replacement. [1, 2]
• Rough Shifting and Binding: Gearboxes require a distinct, un-clutched shift where riders must momentarily ease up on pedal pressure. Shifting aggressively under heavy motor or pedal load causes binding and grinds the internal teeth.
  • Fix: Develop the habit of backing off the throttle and pedals for a split second when twisting the shifter. [1]
• Clicking Noises and Internal Damage: A clicking or clunking noise usually points to poor lubrication inside the casing.
  • Fix: The V-Boxx requires annual re-greasing to prevent catastrophic bearing or gear wear. Remove the gearbox cover and inspect the internal grease—if it's contaminated with dirt or dried up, perform a full cleaning and apply fresh specialized gearbox grease. [1, 2]
• Stiff or Unresponsive Shifter: This can be caused by rust or dirt in the shifter cables rather than a failure of the gearbox itself.
  • Fix: Replace the inner and outer shift cables and lubricate the housing for a smooth pull.

 

[glennb]

Good luck with it.

Indexing for planetary gears does need to be spot on. It can be time consuming.

I'd recommend buying a brand new shifter and precisely measuring the cable pull. In a jig, without housing. Keep those measurements as a reference for theoretical perfection. (Do not trust anybody else's measurements - they're always off).

You can then measure the pull from your setup to compare. If it differs from perfect, install the new shifter. Measure again after that. If it still differs, install new housing and optimise the cable run.

And obviously also flush out the hub, regrease, etc.

 

[coinops]

Thanks glennb, i'll post some photos when the v-boxx is off the bike.

 

[coinops]

i'm not removing the v-boxx off the bike but i have flushed it internally and drained it with a full can of crc 5-56
i got Castrol Spheerol LMM grease to go back in it.

 

[glennb]

Messy job, and bit of effort. But long maintenance intervals for enclosed grars, so could be years before needing to repeat the procedure. Any nasty junk emerge from the flush out?

 

[coinops]

Messy job, and bit of effort.

it was easy actually and i also used the air compressor to blow out the grease and crc oil out of the v-boxx.

Any nasty junk emerge from the flush out?

there was no metal particles in the crc runoff container just the old grease and that still looked clean and the crc oil was slightly discolored, i packed the v-boxx today with grease using a syringe and the v-boxx cranks a bit smoother now.

 

[glennb]

That's good news, if there was any real damage you'd expect particles. Hopefully just an indexing issue then.

 

[coinops]

i did change my mind about removing the v-boxx from the bike too open and inspect it because i can't buy replacement gears/parts for it anyway.
as it is now when turning the crank in reverse only gears 1/3/5 don't click, but gears 2/4/6/7/8/9 do click..i believe it's the internal paws that are worn.
i'll just have to be cautious shifting gears with how it is now, maybe one day it will be serviced by a pro.

 

[scianiac]

I wonder why they used grease in a sealed gearbox like this and not oil? Maybe they couldn't be bothered to actually seal it well enough to hold the oil.

 

[coinops]

I removed the 2 top v-boxx bolts and the bottom drain bolt and sprayed 3/4 of a can of crc 5-56 and turned the crank in each gear slowly and then let it sit overnight.
next day I put the bottom drain bolt back in and sprayed the remaining crc in the v-box and turned the crank slowly in each gear.
I then removed drain bolt and let the crc run out follow by using the air compressor to blow out the remaining crc and old grease then put new grease in.

 

[coinops]

I wonder why they used grease in a sealed gearbox like this and not oil? Maybe they couldn't be bothered to actually seal it well enough to hold the oil.

i would hate to be that B52 owner who looks down under there bike at a puddle of gearbox oil.

 

[coinops]

i added more grease today into the v-boxx and now it's finished.
i forced in a total of 400grams of grease until the grease came out the other holes and it now cranks smoother and quieter than ever.
In comparison the amount of old grease that was blown out was about 30grams..not much at all.

 

[coinops]

i rode 19 km's today to try the new grease job on the v-box, it was a lot better than before.
i should get my new action 4 delivered tomorrow i'm going to zip tie it to the jaw of my helmet.

 

[glennb]

That's a lot of grease. Glad it improved things.

Still hard to understand how there could be significant wear without any crud to clean out. Unless a previous owner flushed it out and regreased.

 

[coinops]

That's a lot of grease. Glad it improved things.

i'm glad i put in new grease it's the best thing iv'e done to the bike.

Still hard to understand how there could be significant wear without any crud to clean out. Unless a previous owner flushed it out and regreased.

i don't think there is much wear in the v-boxx it really was due to a lack of grease that was causing the noise before and it shifts smoother now as well.

Unless a previous owner flushed it out and regreased.

the previous new owner didn't do anything to the bike or even put lithium grease on the chain as it was bone dry when i got it.

 

[glennb]

That's a win then.

Lack of service manual's no excuse for neglecting a chain. The gearbox is understandable though, it can be daunting to disassemble something complicated. Mostly unfounded fear ... it's rare that something's held together in a way that springs go flying when you pop a cover off.