Zongshen 125 valve adjustment

Turbofurball · 01-21-2023, 04:41 PM

Hi, I have a Rieju Tango with a Zongshen 125 engine (it looks like THIS, only muddier), I have no idea what model of engine it is so I've hit a bit of a brick wall in searching for information ... does anyone know what it is, or what the valve gaps should be? Better yet, are there any service manuals available online that would cover this engine?

Any pointers would be gratefully received!

TominMO · 01-21-2023, 05:33 PM

Nice looking bike. The principles of valve adjustment are going to be the same for all these bikes. There are plenty of YT videos on valve adjustment. But I will go find the info I found for another guy today and put it here.....

Go to post #24 on this page: https://www.chinariders.net/showthre...t=31297&page=2

As far as the gap, about .05mm or .002" should be fine for both intake and exhaust for a 125. You could go to .06mm on the exhaust side if you wanted, since exhaust valves do get hotter and therefore the stems expand more. If you have only inch-marked feeler gauges, make the intake a "tight" .002" and the exhaust a "loose" 002".

Megadan · 01-21-2023, 05:51 PM

Quote:

Originally Posted by Turbofurball

Hi, I have a Rieju Tango with a Zongshen 125 engine (it looks like THIS, only muddier), I have no idea what model of engine it is so I've hit a bit of a brick wall in searching for information ... does anyone know what it is, or what the valve gaps should be? Better yet, are there any service manuals available online that would cover this engine?

Any pointers would be gratefully received!

Looks like a clone of an older Yamaha XT125 engine

If that is the case then the specs for those were

Intake: .05 to .09mm
Exhaust: .11 to .15mm

TominMO · 01-21-2023, 06:14 PM

Quote:

Originally Posted by Megadan

Looks like a clone of an older Yamaha XT125 engine

If that is the case then the specs for those were

Intake: .05 to .09mm
Exhaust: .11 to .15mm

If you say so, but .11 - .15mm sounds really loose. Did their exhaust side tend to heat up more than normal? The specs I gave him were for an OHV (CG) Honda motor; .05mm in and ex.

Megadan · 01-21-2023, 09:26 PM

Quote:

Originally Posted by TominMO

If you say so, but .11 - .15mm sounds really loose. Did their exhaust side tend to heat up more than normal? The specs I gave him were for an OHV (CG) Honda motor; .05mm in and ex.

I don't know, ask them. I am relaying their specs.

This is all on the assumption that the engine even is what I said it is. I am going off of one picture that doesn't show much to begin with.

I would need more images of different angles of the head to really be able to identify anything.

That said, valve specs vary from engine to engine for a reason.

TominMO · 01-22-2023, 12:04 AM

Here is the owner's manual in several languages.
https://drive.google.com/file/d/11eG...sBI/view?pli=1

It gives spark plug type and gap, does not address valve clearances.

david3921 · 01-22-2023, 12:36 AM

Other side.

Turbofurball · 01-22-2023, 06:29 AM

Thank you for the helpful suggestions!

With a little image searching I think the engine looks like a modern CG125, like THIS, so I'll go look up how to do the valves on that ... although I have quite a stack of tools I don't have any offset spanners, so I might have to get some of those first!

Bruces · 01-22-2023, 10:12 AM

Have a look low on the engine near the shifter ,there should be a pad with a bunch of numbers letters and girls phone numbers on it ,those numbers will tell you what engine you have instead of guessing .

TominMO · 01-22-2023, 12:27 PM

If it is indeed a CB motor as I thought, then the specs in post #2 do apply.

From Clymer manual M315, which you might want to pick up on Amazon. This is the version I have, which has color wiring diagrams (which may or may not apply to Chinese bikes, IDK). Useful if you have actual Hondas or think you might get one.
https://www.amazon.com/Clymer-Public...s%2C122&sr=8-2

Megadan · 01-22-2023, 06:17 PM

Want to know if it is a CG engine, take the valve cover off. CG is pushrod, the CB and the XT engine mentioned are both OHC.

Turbofurball · 02-18-2023, 03:36 PM

Sorry for the slow response! After reading the above comments I had a moment of clarity ... the engine has a camchain tensioner, so of course it-s OHC, lol

For anyone following in my footsteps, after a little searching I found this guide to be the absolute best (and a huge improvement over anything on Youtube):

https://cbf125rider.wordpress.com/20...on-the-cbf125/

Thank you for your help and prompting, this is one of those cases where I just needed a nudge in the right direction

With the valve clearances done it's now purring along very smoothly again.

01-21-2023, 04:41 PM	#1
Turbofurball Join Date: Jan 2023 Posts: 3	Zongshen 125 valve adjustment Hi, I have a Rieju Tango with a Zongshen 125 engine (it looks like THIS, only muddier), I have no idea what model of engine it is so I've hit a bit of a brick wall in searching for information ... does anyone know what it is, or what the valve gaps should be? Better yet, are there any service manuals available online that would cover this engine? Any pointers would be gratefully received!
	0

01-22-2023, 12:04 AM	#6
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,924	Here is the owner's manual in several languages. https://drive.google.com/file/d/11eG...sBI/view?pli=1 It gives spark plug type and gap, does not address valve clearances. __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
	0

01-22-2023, 12:27 PM	#10
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,924	If it is indeed a CB motor as I thought, then the specs in post #2 do apply. From Clymer manual M315, which you might want to pick up on Amazon. This is the version I have, which has color wiring diagrams (which may or may not apply to Chinese bikes, IDK). Useful if you have actual Hondas or think you might get one. https://www.amazon.com/Clymer-Public...s%2C122&sr=8-2 __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
	0

01-22-2023, 06:17 PM	#11
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,100	Want to know if it is a CG engine, take the valve cover off. CG is pushrod, the CB and the XT engine mentioned are both OHC. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

01-21-2023, 05:33 PM	#2
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,924	Nice looking bike. The principles of valve adjustment are going to be the same for all these bikes. There are plenty of YT videos on valve adjustment. But I will go find the info I found for another guy today and put it here..... Go to post #24 on this page: https://www.chinariders.net/showthre...t=31297&page=2 As far as the gap, about .05mm or .002" should be fine for both intake and exhaust for a 125. You could go to .06mm on the exhaust side if you wanted, since exhaust valves do get hotter and therefore the stems expand more. If you have only inch-marked feeler gauges, make the intake a "tight" .002" and the exhaust a "loose" 002". __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
	0

01-22-2023, 06:29 AM	#8
Turbofurball Join Date: Jan 2023 Posts: 3	Thank you for the helpful suggestions! With a little image searching I think the engine looks like a modern CG125, like THIS, so I'll go look up how to do the valves on that ... although I have quite a stack of tools I don't have any offset spanners, so I might have to get some of those first!
	0

01-22-2023, 10:12 AM	#9
Bruces Join Date: May 2018 Posts: 1,622	Have a look low on the engine near the shifter ,there should be a pad with a bunch of numbers letters and girls phone numbers on it ,those numbers will tell you what engine you have instead of guessing .
	0

02-18-2023, 03:36 PM	#12
Turbofurball Join Date: Jan 2023 Posts: 3	Sorry for the slow response! After reading the above comments I had a moment of clarity ... the engine has a camchain tensioner, so of course it-s OHC, lol For anyone following in my footsteps, after a little searching I found this guide to be the absolute best (and a huge improvement over anything on Youtube): https://cbf125rider.wordpress.com/20...on-the-cbf125/ Thank you for your help and prompting, this is one of those cases where I just needed a nudge in the right direction With the valve clearances done it's now purring along very smoothly again.
	0