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Not suggesting 2mm more base gasket. Recommending 2mm (or any other value your experiments show to be helpful) total squish clearance. The squish may already be on the order of 1.2mm. Yes, it will change the port timing, but I have not seen that small change cause negative side effects. If anything, it makes the bike slightly easier to kick. It's also easily reversible. The Sherco uses o-ring seals for the head/cylinder interface, which I would leave alone. Machining the head is another, less reversible, route. Increasing the combustion chamber's “blend radius” is another way to soften the hit. I touch on that here: https://www.ossa-efi.com/home/engine/heads Also, a bit on reeds here: https://www.ossa-efi.com/home/engine/reed-valves I'm going to retract my G2 idea based on RonH's experience. I now see it's intended to be a blend of the slow and fast rates. Whereas Ron's idea for a “slower than slow” tube is more what you need.

I like your suggestion with the cam. Thank you for your help.

Adding 2mm to base gaskets will also change the port timing slightly, whereas increasing the head gasket will not. Is it your recommendation to lower compression AND change port timing by using a base gasket, or just to lower compression by using a head gasket?

Two cheap, easy, reversible changes: Retard ignition timing. Increase squish clearance to ~2mm via additional base gaskets. Additionally, if you are good with the clutch, a flywheel weigh can help slow things down. A company called G2 makes a cammed throttle tube called the Tamer: https://www.g2ergo.com/shop/g2-trials-throttle-tube-progressive-rate-sherco/

www.sherco.com manuals 2012series.

Hey pmcand, I had the exact same problem with my bike. I did three things to help calm my 2023 Gasgas down. 1st - I installed a flywheel weight (it helped some) 2nd - I installed a 1mm head spacer to lower the compression. (It helped a little more, it’s much easier to start too) 3rd - I modified the throttle tube. (This helped a great deal) Regarding the throttle tube, there is a cam where the cable runs around the end of the tube. Both fast and slow throttles have them. I had tried a slow throttle but the change was very minimal so I bought an aluminum one (slow again) from G2 Ergonomics. It also produced no noticeable change that would work for me. I lived with it for two years until I had the idea of modifying the tube. I simply removed the throttle tube and used a Dremel to ease the cam to a more linear pull. It took me about five minutes to grind it down. I have a photo showing how I modified it in the link below. I put a dashed line in to show what material to remove with a before and after shot. The change from a “scary” throttle response was exactly what I needed. It costs nothing to modify it compared to the other mods I listed. I guarantee this, modifying the tube, will get you what you want. Feel free to ask questions. Good luck! https://flic.kr/p/2rPhx56 Oh, we happen to be the same age. When you and I were riding trials in the 70s the throttles were linear and smooth. The new age throttles have the cam we didn’t back then. That quick throttle caused me a serious crash with a punctured lung and six broken ribs. I know exactly what you’re going through. Let me know if the link doesn’t work.

Sell it and buy a 250 is the least amount of messing about.

The throttle on the 2012 is WAAAY too scary. Comes on way too hard with small throttle inputs. What methods are there to calm this beast down? 1) What alternatives are there to slow the throttle cable twist grip? I use the Domino side pull (slow) trials version now. 2) Changes to timing? Advance or retard? 3) Changes to cylinder compression or gasket thickness? 4) Changes to ignition mapping available? 5) Porting mods? 6) Reed mods? 7) Cylinder alternatives? Is there a 250 piston/barrel available that will fit on the 290 engine? I am 65 years old and a expert-level rider in my previous life, so don't give me this "You gotta train harder and get used to it" approach. I don't want to shoot up and over 15' vertical steps...I just want to slow things up a bit.

It is impossible to bounce the rear on the 2012 . Can't even get it off the ground no matter what I do. Front brake is clean and acts like a trigger on a gun, but still won't lift the rear end. Damping is WAAAAAY too slow. Sag is about 10-15mm with no rider. Is there any damping adjustment on the stock 2012 rear shock and where is that bugger anyway?

feetupfun, To be clear I would want to use the KT triples as well, so if using the 175 wheel a spacer would be needed? Still not sure how to anchor the TY brake arm. I think the KT uses a lug cast into the backing plate and lower.

Yes 4 pot front brakes were a huge advance in brake control compared to 2 pot. The EVO also feels substantially lighter to ride than the Techno. I remember riding my first Rev 3 in about 2001 and being amazed at how light it felt to ride compared with a Techno.

I've done it the other way around, fitting TY250 forks to a KT (wanting to increase the trail). I used a TY wheel. An axle spacer was needed for this. It was just an experiment and I went back to using KT forks on my KT. There were two problems with the TY forks on the KT. The amount of trail was too much which upset the steering and the front mudguard hit the exhaust header on full compression of the forks. I then modified some KT triple clamps to provide only about 5mm extra trail over standard and was very happy with the result. If you fit KT forks to a TY250, the KT wheel assembly will be a bit too wide because with KT triple clamps, the fork tubes are slightly (2-3mm) further apart than with TY250 triple clamps. I've not tried to fit a TY wheel to KT forks. KT forks are longer overall and have more travel than TY250 forks and would reduce the trail by about 20-25 mm due to the leading axle design. They are functionally very similar inside with the main difference being that the KT forks do not have anti-topping springs. They are so similar inside that you can use TY internals in KT fork tubes and vice versa. It sounds like a fun, interesting project.

Beta or Vertigo 200 or would be my vote based on the size of the wife and easy of starting. I have known several people who have had smaller riders Daughter's and wife's that have done well on the 200's. If you can't find a 200 I would vote a 125 as my daughter did great on one for a number of years even riding at 3000-6000 ft. If she had stick with it a bit better I probably would have upgraded her to a 200 as that would have made the most sense. However based on the fact that by the time she turned 18 she was 5' 10" 130 lbs and even able to start my 07 4RT 250 (though not great at it) I probably could have gone with most 250's by then. Good luck.

https://www.instagram.com/reel/DSX5PKJDLJs/?utm_source=ig_embed

Has anyone used KT250 forks on a TY? If so, pros and cons? Did you use a KT or TY wheel? If using a TY wheel, how did you mount the brake arm? Possible scenario is KT250 forks used on a TY175 to have larger/stiffer 34mm front end to get rid of the flex with the small 28mm(?) 175 fork. I haven't been able to source a TY250 set and came across a set from a KT. I was also wondering how the leading axle from the KT would work. Hoping someone has tried this over the last 50 years.

Thats worth knowing. thanks Feetup! I must say the ancillaries especially the brakes are much better then the Techno's and they are vitally important much more then the power delivery , I found that out the hard way! I think its a 250 but have not had the head off to confirm, compression is way higher the the evo and you can feel it on the kick starter, she does start normally on the 2nd or 3rd kick after being left for a few weeks. I did measure the bore through the exhaust port when I got her and althouh a rough measurement think it came out at nearer a 250 then a 270 bore. Parts being hard to get now with the tail piece in particular looks almost brand new so not sure I will take her out much unless I can find another tail piece/rear mudguard at a resonable price such is my looping tendancy atm

The only way to find it out is to compare. I have no data about it. The bike feels super light and well balanced. I already assembled the engine back, currently I need to adjust a squish clearance for 1.2 mm. It was 0.9. I ordered 2X0.4 gaskets on top of 0.5 base gasket. Also, the piston feels a bit lightweight and I'm wondering about engine balance.

Does it have the same transmission ratios as the trials engine?

A standard 250 1997 Techno has a lovely soft motor. Technos came out in 1994 and were highly responsive - probably too responsive for the average rider. The 1996 model was made much easier to ride for the average rider and it stayed like this for the rest of the years of the Techno (96, 97, 98, 99). By the way, is your Techno a 250 or a 270?

Thanks for the replies both, well having finally got out to ride the Evo I must say the power is there in abundance! Too much power actually as I flipped the bike at least twice may be three times today , this was more my ineptitude then the bikes fault ofcourse but the geometry of the bike and low gearing and my riding style which was always to muscle the bike around made a lethal combination lol I was thinking of taking the Techno out but I think that could be even more of a handful but I need to do a lot more practicing before entering a trials that for sure........I'll keep the Low compression for the moment , thanks again gents

Then a beginner Trials machine does not currently exist and it's time to find a new hobby.

The EM Factor-e might not be considered a beginner machine (it costs too much for one thing) however the ability to calm it down with adjustable engine maps makes it very suitable in my view. As a rider gains skill and confidence they can increase the available power using the mapping adjustment on the app. The main thing for newbie riders is to ensure the lanyard is on as the bike(s) cannot stall and will continue to drive the back wheel after you fall off. Electric bikes are not affected by altitude either. Well worth getting a test ride if you can. Petrol is still a better option for road bikes in my opinion and may well be for many years to come, but for trials the battery bike is a very sensible choice.

Hi, Is it possible to use 1975-1976 LH and RH crankcases from YZ125 with the all the components and covers of TY175?

We've had both 125cc and 200cc Shercos in the stable. The 125 is easier to kick. My wife transitioned from the 125 to the 200, but it took a toll on her knee (which was pretty beat up from running). For infrequent starts during trail riding, it may not matter. But repeated starting during competition may be a problem. I found the older Ducati Energia ignition system more reliable than the newer Leonelli. 2004/2005 was around the changeover point.

No I can't, I did check it for several times. My bike identifies as a trial, according to the VIN number but there is a lot of difference. I’m blaming the carb, it was running on lean and that caused a cold seizure. I have no data on factory settings. I like this bike, it's a bit different. I'm going to keep it in along term and that's why I'm trying to find out all potential issues.