Rear shocks to suit a TY175 would be suitable for the Cota 247.
Forks are rebuildable, you just need to get some high pressure rotary seals of matching dimensions from your local supplier.
I'd be checking your countershaft sprocket before pulling anything apart, if its worn it might be catching the chain.
Next thing would be as JRSUNT has said and take the chain off and run it in gear and see if noise is affected by the clutch, which means you will have to dig further.
The Beta 4 stroke is super smooth if you are going with a 4 stroke, might be a better option than the Montesa if you thought the 2 stroke was a handful.
Are you trying to start it with the Carby choke on?
Will it start once it has been started and warmed up?
I would also check the plug lead is screwed in properly, if that was changed with the electronic ignition.
I kick mine left footed fine but it does have a bit of compression.
I would recommend that you remove the high compression head which is fitted to the factory model and put on a low compression one like they fit to the standard model.
Good quality gear oil to suit a trials bike.
Moving the lever location on the bars so you are pulling further out on the lever.
Depending on how low low hours is 2017 is also old enough you might want to consider filing any ridges that exist in the clutch basket tabs from wear with the clutch plates.
EBC are ok but they are not peak performance which you seem to be after.
An example of someone who does it below but you coould find someone who does it for forklifts or the like locally to you.
https://villiersservices.co.uk/product/brake-shoe-re-lining-service/
It takes some time for pads to bed in and have full contact with the drum.
You might want to go down the path of having pads of a suitable friction material applied to the brake shoe so you can match the diameter of your drum.
What happens if you give the throttle a big blip when it starts revving up?
Could also be starved of fuel if there is not an air leak as Lemur has suggested.
When you pull the clutch lever in I assume you can feel the mechanism trying to activate the clutch?
Also I assume you have tried riding it in a high gear with the clutch pulled in while accelerating?
On my gasgas enduro bike I went to the shop and bought a cheap ring spanner and ground the outside down until it fit.
Scientific torque spec I used was almost as tight as I could do it by hand and then give the the spanner a couple of light hits with a hammer.
Trials bikes are normally fairly difficult to change into neutral, I normally just turn my bike off then put it into neutral.
On the odd occasion you can knock it into neutral with it running but its certainly not really easy.
https://www.trialsbike.com.au/product/ossa-5020040211-air-filter-box-lid/
Was an Ossa dealer at the time, so he may still have a stand if you send him an email.
