Zongshen Sierra Speedometer drive unit

ChillRider · 12-03-2021, 04:54 AM

OK, after being on its last breath for the last year or so, the speedometer drive at the front wheel finally gave up the ghost and the speedo needle doesn't move at all. The odometer still *kinda* moves... at a ratio of 100m for every 10 km ridden or so.

In the meantime it went through all phases like e.g. jumping the speedo needle, moving erratically, registering a fraction of kms ridden on the odometer etc., I've also tried everything else like lubricating the cable, replacing the cable, replacing the speedometer itself etc., so that's it for half-measures.

The problem is that my only known source for speedo drive units for this motorcycle, china-parts.co.uk, has it "out of stock" since forever.

The unit itself looks like this:

It is a right-hand unit, BTW. I've tried looking at photos of other speedo drives in online parts shops and eBay and even aliexpress listings to find one that looks close enough, but no luck. Either the notches were incorrectly positioned, or they were left-hand units, or the spindle hole was too small (it should be 12mm), or all of the above.

Any ideas where I could find a source for this speedo, or at least a compatible one from a different make of motorcycle? Even being able to swap out the plastic core gear with a similar one from an otherwise incompatible unit would be enough, without resorting to machining one from scratch.

Edit: FWIW, there seems to be a passing resemblance with the Kawasaki Kaze-R speedo drive unit:

The only obvious difference is that the spindle hole is smaller, but that can probably be swapped out:

Since these are quite affordable, I'll order one and see how it goes from there, reporting back in case this helps anyone.

JohnC · 12-03-2021, 09:25 AM

I would check on Aliexpress. They may have these as well. I picked up a digital speedo from them that allowed me to put in the wheel size, which made it more accurate than the original.

John

ChillRider · 12-06-2021, 02:36 PM

Strangely, AliExpress hadn't got the Speedo unit, even though it carries other OEM (!) ZongShen parts for this model. The closest there is on terms of looks, is a Yamaha YBR speedo drive, but I think the bushing's hole is larger.

I have considered a digital speedo conversion too (using a bicycle computer and a magnetic sensor near the front disk brake), but I'd like to keep the instruments as stock.as possible. No idea how aftermarket digital speedos work though....do they bypass the gears + cable, just like a bicycle computer?

ChillRider · 12-08-2021, 07:15 AM

An update: I ordered 3 Kawasaki Kaze-R speedo units, dirt cheap as I mentioned, and all different makes in order to do some mix & match experimenting.

Some measurements for reference: the outer shell diameter for all of them is identical to the Zong OEM unit (55 mm), as is the diameter of the threaded cable connection (12 mm). The outer diameter of the inner metal bushing is 20 mm, which should also be the same as the Zong's, judging from the pics of the OEM part. The Kaze-R speedo cable also seems to be of the same length and attachment type as the Zong OEM one.

What is almost certainly different however, is the diameter of the axle hole: 10 mm on the Kawa unit, probably 12mm on the Zong just by measuring pixels on the pic. I will only confirm this once I have the front wheel removed at a mechanic's.

I tried to take some of these speedos apart, to see if it's possible to swap out the toothed gears between them. It sorta works, because they are not all made equal: the width of the toothed surface in particular is not equal, some need top/bottom spacers, some have slightly larger bushings/slightly tighter holes for the gears, some don't turn as well when matched with a different core etc. Hopefully one of them will fit my Zong

So, at least when using Kawa units, the best bet seems to be to reuse the center gear (which should at least fit over the metal bushing). Alternatively, it should be possible to bore the axle holes up to 12 mm and use the new unit directly, rather than Frankensteining parts.

ChillRider · 12-17-2021, 08:53 AM

Yet another update: for some reason, I had an epiphany and asked to myself "Well, how do I know the Kawasaki unit will rotate in the correct direction? Is it even mounted on the same side of the wheel?".

So I checked and... you guessed it, it's all backwards

: the Zong, with its Yamaha-style speedometer (and OEM speedos too) require a CCW rotation of the cable, if looking up the cable's sleeve starting at its attachment point to the speedo drive.

The Kawa unit, if mounted on the Zong's right fork, will also rotate CCW's if looking down the shaft....which unfortunately will become CW once mated to the cable. So at this point I need either a reverser unit (does such a beast even exist?), or a complete rethinking of this whole thing

buzz · 12-17-2021, 03:01 PM

Hey just drive with out it,won't be a big deal for.

ChillRider · 12-20-2021, 09:15 AM

Well sure, it's not like it's not rideable without it, but it makes it harder to keep track of intervals such as oil changes and even refueling, unless you like looking down the tank every now and then.

More importantly, I'm not sure if it can pass an MOT without a working speedo/odometer. Changing odometers is already somewhat of an issue, having a completely non-working setup is another.

ccubanito · 01-29-2022, 10:15 AM

i'm sorry for putting this question here but this is one of the newest post that I have seen. I recently got a 2006 zongshen sierra 200 and it was kept by the river so is pretty rusted. I'm trying to find a wiring harness for it. Would you happen to know if there is a wiring harness compatible with this bike that i can purchase? Thank you

ChillRider · 02-01-2022, 08:31 AM

The only places that are likely to have OEM/compatible spare parts, are China Parts Co. Ltd in the UK (they refer to it as the Zipstar ZS200GY-2), and aliexpress.

A few portions of the wiring might be compatible with the equivalent Yamaha TW200/Serrow/XT200/XT225 ones, but you need to look at photos and connectors to be 100% sure. Which parts of the harness/elecrical system do you need replaced? All of them?

ChillRider · 02-09-2022, 09:10 AM

Yet another update: the only place in the world that seems to stock the Zongshen original speedo drives is this seller on aliexpress:

https://www.aliexpress.com/item/1005002409541300.html

Of course I ordered one, along with some other spare parts, pre-emptively. This also confirms my guesstimate of the front hub spindle being 12 mm. The outer casing dimensions and overall shape also match those of the aforementioned Kawasaki Kaze-R unit (but also those of the Yamaha YBR125 speedo).

The catch with original Yamaha and Kawa units however is that they are mounted "backwards" so to speak, on the left side of the hub, so they would spin in the wrong direction if installed as-is on the Zong, even if you matched the different spindle diameter (Yamaha units have 15mm holes, Kawa units have 10 mm ones).

Thumper · 02-09-2022, 01:11 PM

Chill,
Are you sure it is the drive unit on the axle? The symptoms could suggest the cable or the speedo itself as well. Maybe I missed this in your posts, so sorry if I am barking up the wrong tree, but maybe you can use a drill to turn the speedo input directly and see how it responds. I can't think of anything lighter like a12V motor or something, but the chuck might pinch the input post if it is a post like I've seen on Japanese bike (square post).

To check the cable, disconnect from the speedo and spin the front wheel as fast as you can and see if the speedo end of the cable is rotating normally (or you can just tape the speedo cable up to the side of the front fairing and just drive the bike, see if the thing is spinning in there).

If the cable doesn't turn when the sender device is rotated, it may also be possible to pry open the sender device and see if the worm gear is actually worn or broken? It might even be fixable.

ChillRider · 02-09-2022, 02:29 PM

Yeah, I've been watching it die for a year or so now. I cleaned and swapped the cable twice, even swapped the speedo itself with a brand-new Yamaha XT600 unit, and tried driving both of them with a drill, using both new and old cables. When driven by the drill, both speedos were smooth as butter.

At some point the teeth on the gear drive unit at the hub must have started failing one by one, since the indicated speed/distance only dropped by suspiciously specific fractions (e.g. 10/11, then 7/8, then 3/4ths of the actual etc.) as more and more teeth failed. At some point enough teeth failed that tne needle started jumping up and down, first a bit, then a lot. If you get enough bad teeth then the pinion start smashing against the remaning ones, as it constantly meshes + unmeshes, accelerating the damage. It took one year to degrade from "10/11" mode to "7/8", and from that it went to "3/4" to complete nothing in less than a month. I have documented this agonizing process here.

Cleaning/replacing the cable only bought me maybe a few kms of smoother operation, the needle jumping decreased but never totally went away, and the indicated speed/distance always remained at a specific fraction of what it was supposed to be...as a function of the number of missing teeth. Then, one day it completely died, as whatever teeth remained just got ground away against the metal pinion

Well, it's to be expected. Many of those units have plastic gears (the pinion was metal in my case), and they have a finite lifetime. Mine were 13 yo and saw nearly 30.000 km of use, of which 10.000 km only in the last two years when I rode the bike.

Thumper · 02-09-2022, 03:28 PM

Of course... You've been down this road. Then there is only one fix... the axle mounted sender.

I have had one speedo cable fail on me. I think it was my first bike (a used 1975-ish Suzuki TS250 dirt bike), The sending unit was OK, and the speedo was OK, but the cable would spin erratically and I could hear it binding and releasing inside the housing. A new cable fixed it in that case. I immediately filled the housing with graphite before I even installed it. Whisper smooth!

12-03-2021, 04:54 AM	#1
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	Zongshen Sierra Speedometer drive unit OK, after being on its last breath for the last year or so, the speedometer drive at the front wheel finally gave up the ghost and the speedo needle doesn't move at all. The odometer still kinda moves... at a ratio of 100m for every 10 km ridden or so. In the meantime it went through all phases like e.g. jumping the speedo needle, moving erratically, registering a fraction of kms ridden on the odometer etc., I've also tried everything else like lubricating the cable, replacing the cable, replacing the speedometer itself etc., so that's it for half-measures. The problem is that my only known source for speedo drive units for this motorcycle, china-parts.co.uk, has it "out of stock" since forever. The unit itself looks like this: It is a right-hand unit, BTW. I've tried looking at photos of other speedo drives in online parts shops and eBay and even aliexpress listings to find one that looks close enough, but no luck. Either the notches were incorrectly positioned, or they were left-hand units, or the spindle hole was too small (it should be 12mm), or all of the above. Any ideas where I could find a source for this speedo, or at least a compatible one from a different make of motorcycle? Even being able to swap out the plastic core gear with a similar one from an otherwise incompatible unit would be enough, without resorting to machining one from scratch. Edit: FWIW, there seems to be a passing resemblance with the Kawasaki Kaze-R speedo drive unit: The only obvious difference is that the spindle hole is smaller, but that can probably be swapped out: Since these are quite affordable, I'll order one and see how it goes from there, reporting back in case this helps anyone. Last edited by ChillRider; 12-03-2021 at 05:35 AM.
	0

12-17-2021, 08:53 AM	#5
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	All wrong Yet another update: for some reason, I had an epiphany and asked to myself "Well, how do I know the Kawasaki unit will rotate in the correct direction? Is it even mounted on the same side of the wheel?". So I checked and... you guessed it, it's all backwards : the Zong, with its Yamaha-style speedometer (and OEM speedos too) require a CCW rotation of the cable, if looking up the cable's sleeve starting at its attachment point to the speedo drive. The Kawa unit, if mounted on the Zong's right fork, will also rotate CCW's if looking down the shaft....which unfortunately will become CW once mated to the cable. So at this point I need either a reverser unit (does such a beast even exist?), or a complete rethinking of this whole thing
	1

12-03-2021, 09:25 AM	#2
JohnC Join Date: Oct 2020 Location: Southeast Michigan Posts: 99	I would check on Aliexpress. They may have these as well. I picked up a digital speedo from them that allowed me to put in the wheel size, which made it more accurate than the original. John
	0

12-06-2021, 02:36 PM	#3
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	Strangely, AliExpress hadn't got the Speedo unit, even though it carries other OEM (!) ZongShen parts for this model. The closest there is on terms of looks, is a Yamaha YBR speedo drive, but I think the bushing's hole is larger. I have considered a digital speedo conversion too (using a bicycle computer and a magnetic sensor near the front disk brake), but I'd like to keep the instruments as stock.as possible. No idea how aftermarket digital speedos work though....do they bypass the gears + cable, just like a bicycle computer?
	0

12-08-2021, 07:15 AM	#4
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	An update: I ordered 3 Kawasaki Kaze-R speedo units, dirt cheap as I mentioned, and all different makes in order to do some mix & match experimenting. Some measurements for reference: the outer shell diameter for all of them is identical to the Zong OEM unit (55 mm), as is the diameter of the threaded cable connection (12 mm). The outer diameter of the inner metal bushing is 20 mm, which should also be the same as the Zong's, judging from the pics of the OEM part. The Kaze-R speedo cable also seems to be of the same length and attachment type as the Zong OEM one. What is almost certainly different however, is the diameter of the axle hole: 10 mm on the Kawa unit, probably 12mm on the Zong just by measuring pixels on the pic. I will only confirm this once I have the front wheel removed at a mechanic's. I tried to take some of these speedos apart, to see if it's possible to swap out the toothed gears between them. It sorta works, because they are not all made equal: the width of the toothed surface in particular is not equal, some need top/bottom spacers, some have slightly larger bushings/slightly tighter holes for the gears, some don't turn as well when matched with a different core etc. Hopefully one of them will fit my Zong So, at least when using Kawa units, the best bet seems to be to reuse the center gear (which should at least fit over the metal bushing). Alternatively, it should be possible to bore the axle holes up to 12 mm and use the new unit directly, rather than Frankensteining parts.
	0

12-17-2021, 03:01 PM	#6
buzz Join Date: Dec 2020 Location: Dayton Pa. Posts: 862	Hey just drive with out it,won't be a big deal for.
	0

12-20-2021, 09:15 AM	#7
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	Well sure, it's not like it's not rideable without it, but it makes it harder to keep track of intervals such as oil changes and even refueling, unless you like looking down the tank every now and then. More importantly, I'm not sure if it can pass an MOT without a working speedo/odometer. Changing odometers is already somewhat of an issue, having a completely non-working setup is another.
	0

01-29-2022, 10:15 AM	#8
ccubanito Join Date: Jan 2022 Posts: 4	i'm sorry for putting this question here but this is one of the newest post that I have seen. I recently got a 2006 zongshen sierra 200 and it was kept by the river so is pretty rusted. I'm trying to find a wiring harness for it. Would you happen to know if there is a wiring harness compatible with this bike that i can purchase? Thank you
	0

02-01-2022, 08:31 AM	#9
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	The only places that are likely to have OEM/compatible spare parts, are China Parts Co. Ltd in the UK (they refer to it as the Zipstar ZS200GY-2), and aliexpress. A few portions of the wiring might be compatible with the equivalent Yamaha TW200/Serrow/XT200/XT225 ones, but you need to look at photos and connectors to be 100% sure. Which parts of the harness/elecrical system do you need replaced? All of them?
	0

02-09-2022, 09:10 AM	#10
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	Yet another update: the only place in the world that seems to stock the Zongshen original speedo drives is this seller on aliexpress: https://www.aliexpress.com/item/1005002409541300.html Of course I ordered one, along with some other spare parts, pre-emptively. This also confirms my guesstimate of the front hub spindle being 12 mm. The outer casing dimensions and overall shape also match those of the aforementioned Kawasaki Kaze-R unit (but also those of the Yamaha YBR125 speedo). The catch with original Yamaha and Kawa units however is that they are mounted "backwards" so to speak, on the left side of the hub, so they would spin in the wrong direction if installed as-is on the Zong, even if you matched the different spindle diameter (Yamaha units have 15mm holes, Kawa units have 10 mm ones).
	0

02-09-2022, 01:11 PM	#11
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,313	Chill, Are you sure it is the drive unit on the axle? The symptoms could suggest the cable or the speedo itself as well. Maybe I missed this in your posts, so sorry if I am barking up the wrong tree, but maybe you can use a drill to turn the speedo input directly and see how it responds. I can't think of anything lighter like a12V motor or something, but the chuck might pinch the input post if it is a post like I've seen on Japanese bike (square post). To check the cable, disconnect from the speedo and spin the front wheel as fast as you can and see if the speedo end of the cable is rotating normally (or you can just tape the speedo cable up to the side of the front fairing and just drive the bike, see if the thing is spinning in there). If the cable doesn't turn when the sender device is rotated, it may also be possible to pry open the sender device and see if the worm gear is actually worn or broken? It might even be fixable.
	0

02-09-2022, 02:29 PM	#12
ChillRider Join Date: Jun 2020 Location: A small country with a funny name Posts: 164	Yeah, I've been watching it die for a year or so now. I cleaned and swapped the cable twice, even swapped the speedo itself with a brand-new Yamaha XT600 unit, and tried driving both of them with a drill, using both new and old cables. When driven by the drill, both speedos were smooth as butter. At some point the teeth on the gear drive unit at the hub must have started failing one by one, since the indicated speed/distance only dropped by suspiciously specific fractions (e.g. 10/11, then 7/8, then 3/4ths of the actual etc.) as more and more teeth failed. At some point enough teeth failed that tne needle started jumping up and down, first a bit, then a lot. If you get enough bad teeth then the pinion start smashing against the remaning ones, as it constantly meshes + unmeshes, accelerating the damage. It took one year to degrade from "10/11" mode to "7/8", and from that it went to "3/4" to complete nothing in less than a month. I have documented this agonizing process here. Cleaning/replacing the cable only bought me maybe a few kms of smoother operation, the needle jumping decreased but never totally went away, and the indicated speed/distance always remained at a specific fraction of what it was supposed to be...as a function of the number of missing teeth. Then, one day it completely died, as whatever teeth remained just got ground away against the metal pinion Well, it's to be expected. Many of those units have plastic gears (the pinion was metal in my case), and they have a finite lifetime. Mine were 13 yo and saw nearly 30.000 km of use, of which 10.000 km only in the last two years when I rode the bike.
	0

02-09-2022, 03:28 PM	#13
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,313	Of course... You've been down this road. Then there is only one fix... the axle mounted sender. I have had one speedo cable fail on me. I think it was my first bike (a used 1975-ish Suzuki TS250 dirt bike), The sending unit was OK, and the speedo was OK, but the cable would spin erratically and I could hear it binding and releasing inside the housing. A new cable fixed it in that case. I immediately filled the housing with graphite before I even installed it. Whisper smooth!
	0