Sherco TY 125F Classic and Scorpa TY 125F

[stpauls]

Sherco or Scorpa TY 124 4T Classic or Adventure, 2018 onwards.
I have read much in the media about the 2018 and later Sherco and Scorpa TY 125 4T Classic and/or Adventure. Some of it is completely wrong!
If you want a small, 4T Trials bike then your choice is very limited. For use in Novice Trials sections, this bike is quite good, but only IF you do some work to it first.

The engine is made by Jianshe-Yamaha, in China. It is a clone of a Yamaha TTR / YBR. The engine parts are mostly interchangeable. The factory is part-owned by Yamaha. Any small Yamaha motorcycle purchased in Europe now has it's engine made by Jianshe - Yamaha, in China - even if it says Yamaha on the engine cases!
The carburettor is a Mikuni BS25. Used in some quads. Due to very restricted avaliable space, it is a good compromise carburettor for this bike.  The standard jetting is: pilot/slow jet = 17.5. The main jet is 130. If you fit a 150cc big bore kit, you need to increase the size of the main jet to 150.  Increasing the size of the slow/pilot jet also improves slow running,  bottom end torque and aids starting.

If you want to use it competitively for Trials, then the minimum you will need to do is:
1. Change the tires - Michelin trials tires. Or, Michelin front, IRC on the rear.
2. One tire clamp on the front. Two tire clamps on the back.
3. Put a spring tip on the rear brake lever.
4. Replace the exhaust pipe and CAT with a pipe from S3, or, buy an even better one from: Iron Davis at Excel Engineering, in the UK: 01554     751935.  Same price.

 

Additionally, for a much better, competitive trials bike:
5. The clutch is quite stiff and very on/off. Make the clutch actuator arm longer to make the pull lighter and to provide more control. I also removed the hydraulic clutch on mine and replaced it with an ordinary clutch lever. Much, much better clutch control.
6. Fit an in-line fuel filter. The pilot jet hole is tiny and it's hassle to get to, to clean it.
7. I found mine to be a bit quick in the Sections, so, as the engine sprocket is already very small, Talon, in Yeovil made me a one-off 63 tooth rear sprocket, to replace the standard 57 tooth.  This also allows 2nd gear to be used in some sections.
8. Remove all the lights, horn etc. Install a Stop Switch.
9. I removed the heavy battery and heavy starter motor from mine and repositioned all the electrics to up near the steering head. Additionally, removed the starter motor gears from inside the engine. The kick start works fine. Remove the spring from the right hand foot peg to enable the kickstart to clear the footpeg.
10. The engine cases overhang the standard bash plate by quite a bit. You can buy a proper, flat one from Excel Engineering, in the UK: 01554 751935
11. DO NOT Remove 5mm from the carburettor overflow tube (a tiny brass tube, inside of the float bowl).   (This modification was recommended by Scorpa).  However, if you adjust the float level in the carb properly (and possibly increase the pilot jet 1 size up} then this modification is NOT necessary. (I cut 5mm off mine, then had to solder 5mm back on after I had sorted the carb out.  It now starts first kick, every time!
12. Fit a big bore kit and bigger jets: New Sherco Trials 125 4T 150cc Big Bore Kit Straight Fit Oe Yamaha Cyl & gaskets | eBay

13. Remove the big engine sprocket guard - leaving the small one in place.

Main jet: 130 is standard. 1 tried a 140, then a 150. 150 workes well. Mikuni Main Jets 8mm Round Head Carb Carburettor # N100.604 | eBay

The slow/pilot jets are unusual and not listed anywhere. It took me ages  to identify a similar jet. The standard 17.5 is the same jet hole size as a 35 in these!   I fitted a 40 which works better. They are here: 12xCopper Carburetor Slow Pilot Jet Assembly for PZ19 PB16/18/20 Carb | eBay

Front forks.  No oil drain bolts, so you have to remove each fork leg to drain the oil.  300 ml of 5W in each leg.

Engine oil.  Use a Mineral engine oil, not Synthetic or Semi-synthetic, to avoid clutch slip or judder.

Hope this helps.

 

Edited November 13, 2023 by stpauls
Updated and added further information.

[cleanorbust]

Good of you to detail the mods to make the bike competitive. I think you're quite an experienced rider - how do you feel  about the bike in comparison to the mainstream two strokes for trials use?

Lastly, are there any differences between the Sherco and Scorpa?

[gazzaecowarrior]

11 hours ago, stpauls said:

Sherco or Scorpa TY 124 4T Classic or Adventure, 2019 onwards.

 

If you want a small 4T Trials bike to use in Novice sections, then your choice is very limited.  This bike is quite good IF you do some work to it first.

 

The engine is a Jianshe 125 6C, made by Jianshe-Yamaha, in China. It is a clone of a Yamaha TTR.  The engine parts are interchangeable.   The factory is part-owned by Yamaha.  Any small Yamaha motorcycle purchased in Europe has it's engine made by Jianshe - Yamaha, in China - even if it says Yamaha on the engine cases!  

The carburettor is a Mikuni BS25.  Used in some quads.  It is a good carb for this bike.  The standard jetting is: pilot/slow jet = 17.5.  The main jet is 130.  If you fit a 150cc big bore kit, you need to increase the size of the main jet to 150.

 

If you want to use it competitively for Trials, you will need to:

Minimum:

1.  Change the tires - Michelin trials tires. Or, Michelin front, IRC on the rear.

2.  One tire clamp on the front.  Two tire clamps on the back.

3.  Put a spring tip on the rear brake lever.

4.  Replace the exhaust pipe and CAT with a pipe from S3, or, buy an even better one from: Iron Davis at Excel Engineering, in the UK: 01554 751935.  Same price.

Additionally:

5.  The clutch is quite stiff and very on/off.  Make the clutch actuator arm longer to make the pull lighter and to provide more control.  I also removed the hydraulic clutch on mine and replaced it with an ordinary clutch lever.  Much, much better clutch control.

6.  Fit an in-line fuel filter.  The pilot jet hole is tiny and it is hassle to get to, to clean.

7.  I found mine to be a bit too quick in the Sections, so as the engine sprocket is very small, Talon, in Yeovil made me a 63 tooth rear sprocket, to replace the standard 57 tooth. 

8.  Remove all the lights, horn etc.  Install a Stop switch.

9.  I removed the heavy battery and heavy starter motor from mine and repositioned all the electrics up near the steering head.  Additionally, removed the starter motor gears from inside the engine.  The kick start works fine.  Remove the spring from the right hand foot peg to enable the kickstart to clear the footpeg.

10. The engine cases overhang the standard bash plate by quite a bit.  You can buy a proper one from Excel Engineering, in the UK: 01554 751935

 

Hope this helps.

Thanks for the info. That is very helpful. What is the suspension front and rear like ?

[stpauls]

On 12/1/2022 at 7:45 AM, cleanorbust said:

Good of you to detail the mods to make the bike competitive. I think you're quite an experienced rider - how do you feel  about the bike in comparison to the mainstream two strokes for trials use?

Lastly, are there any differences between the Sherco and Scorpa?

I rode new Sherco 250 and 125 two strokes for several years and before that Beta two strokes, competing in Trials - usually Novice sections every week.  The first thing I always did was to explore methods for softening the power delivery -  flywheel weight, low compression head, retard the ignition, smaller/larger sprockets etc.

I tried a Sherco TY125F, but in my opinion it is a Trail bike, not a dedicated Trials bike.   "Sherco have no interest in developing this bike for Trials - we just sell them" - quote.  Scorpa did limited developement work on a couple of these bikes in 1919, but no longer do so.  To make them competitive you will have to do it yourself!  (Luckily, in a former life I worked as an Engineer).

The power delivery is different on a two stroke, because as the engine revs climb, so the power increases.   On this 4 stroke, the power is less, but there is no step-up in power as the revs climb - no power band, just smooth, constant power.  Much softer, tractable and controllable power.

The Sherco and Scorpa TY 125F are exactly the same, just different graphics.

The suspension is fine - as good as on a comparable modern Sherco 125 or a Sherco 250 two stroke (owned both and rode regularly in Trials).  The front forks on the TY125F are different from the Sherco 2 strokes, but work well.   (The frame and geometry are exactly the same on all of the bikes - only the front down tube is different). 

Ground clearance is a bit less on the TY125F - perhaps by 25mm.  Lighter riders likely wouldn't notice it !!!

Brakes are excellent.

Fuel consumption is much less than on Sherco two strokes!

This uprated rear suspension spring fits, should you need it! :  Beta EVO 2T/4T Sachs Heavy Duty Rear Spring - 2015 Onwards - GasGas Sherco Beta | eBay

 

Edited December 28, 2022 by stpauls

[stpauls]

Update:

Out of interest I bought a 163cc bigger bore kit.  This is the same as is used on the old Scorpa TY 200.  This needed a COMPLETE strip down of the engine, to enable the crank cases to be bored out to accommodate the bigger cylinder sleeve. 

It was quite straight foward.  The only issue that I had was that the two tangs on the bottom of the piston had to be 50% removed so as not to touch the crank shaft balancer.  I also needed an even thicker base gasket than that provided, to reduce compression, so I made an additional one out of 1mm aluminium.  

Ridden in several trials since completed.  No issues.  More pulling power in the lower rev range.