lemur

How close is this to what you have? http://ossa.2y.net/ossa/onlinemanuals/ossa5speedmanual/Page124.jpg

Transmission and wet clutch oil actually, since it is not a 4-cycle engine. You are looking for a lubricant (oil) that is suited to the operating temperature you are likely to be running in. I use all season hydraulic excavator oil which is ISO46 why because I buy it in 5 gallon pails and it works as good in a motorcycle transmission as it does in a farm tractor transmission or excavator that is full of gears and wet clutches. More important is that you keep the oil clean and free of water, so change it frequently which is going to happen a lot more frequently if you are buying it at 7$ per litre and not 20$ per litre. Viscosity charts will show you where !SO46 fits relative to other lubricants. What you don't need in a manual transmission and wet clutch is multi-grade 4-stroke engine oil with friction modifiers.

Some days nothing seems to want to work good

Easy to cook a rear brake by dragging it against the engine power, front brake not so much if you don't have pavement. Last time I had a trials bike front brake steaming hot on trials terrain was never.

Blow torch or do you do this on pavement?

I just sand them dry and put them on dry to break them in. One thing I did run across recently was wedge shaped pads, one end contacted before the other. I had to keep sanding the high side until the pad face was parallel to the steel backing plate. Might want to watch for that, they performed poorly out of the package. Bought a set of pads with lots of brass flakes in them, those were garbage and I went back to Galfer reds.

You have to buy a GasGas service manual? that sucks, it should come with a new bike.

Hints for all on reassembly; torque charts are based on wet threads not dry. Service manuals or the net sometimes give inappropriate torque values, triple check them because many confuse inch pounds with foot pounds during conversion, or they are just printed wrong. If you are not using a 1/4" drive torque wrench on M6 or M8 bolts it might be the wrong tool for the job, I've also seen people not use the handle correctly, the handle pivots at the correct distance to the tool, it doesn't flop back and forth like that without reason. If unfamiliar with operation practice on something that does not matter first. 👍

If all else fails; see if the casting will take aluminum weld, fill the holes with weld, drill new holes and tap them to the standard size.

Biggest difference other then cost: HeliCoil is a coil spring and will not provide a watertight repair at the threads. TimeSert sells a threaded insert and threads can be made to seal water pressure if you end up drilling into the water jacket. Using a drill press to start the tap straight into the clearance hole is a good practice. The manufacturers catalogue will detail the size of the clearance hole required.

Did it come with a white or a black throttle (fast or slow). imo That makes a huge difference to the engine response for very little cost.

Fish Glue would still work far better, a tube needs some form of rim lock. ... but lemur, why use fish glue and not something else? <- because you can reactivate it any time by adding water 🤓

How long was it in the ocean?

You're not going to believe this but Fish Glue I use it in winter tires that are full of screws and sidewall splits, it's water soluble and non toxic for easy cleanup. Not expensive and available from stores that cater to woodworking.

Biggest difference to some people is the kick starter on the opposite side.

That's why there are so many burn marks on the inside right leg of all my riding pants, there is raw flame going through that little single walled header pipe.

Is it ownership registered? Nobody can guess at the value when we don't even know what country the bike is in, are we shopping in euros, US$ or loonies? That looks to be about a 3200 loonie motorcycle here in Canada which might mean nothing depending on where you live. Less value if it can not be plated for off-road use because that would make it ridable only on private land and in closed course competition events. ymmv

Whisky throttle is when you experience a brief disconnect between your brain and your physical dexterity. I can tell you're not addicted to the sport yet, but once you do become comfortable with the controls and start moving with your machine instead of just using it to haul you around like a wagon, then you will become addicted to riding trials bikes. What they didn't tell you at the dealership is; you didn't just buy some vehicle to transport you over terrain so rough that it could kill a horse, you bought an exercise machine that requires riding every chance you get until you get really good with it. Master the controls first and learn to read the terrain, learn to move your body in harmony with the motorcycle while practicing the technique' of doing wheelies, splats, zaps, hops and all those other neat tricks. The motorcycle does not make it easy, it only makes it possible and about 4 days or more per week is usually required to notice a marked improvement in your riding skills and physical endurance, much less than 2 days per week riding will have you regressing in skills and physical conditioning just as it would happen with any other strenuous exercise regime.

Sweet bike! From here the fuel tank and possibly even the frame looks like it came straight off an AJS Stormer.

Trouble-shooting and always having replacement parts on hand is the biggest reason to buy trials bikes in pairs, nothing beats having a second bike of the same model and swapping entire assemblies until you locate the problem, especially when a carburetor, throttle body or CDI module is in question. ... any friends that own the same model bike? That can work too.

I concur with the above post, you likely need to ride the foot pegs far more and the handlebars far less. Infinitely better to assist if we could see what you are doing wrong but just a guess: The number one new to trials rider issue is not bending your knees anywhere near enough because doing so moves your body weight off the bars and lowers your weight onto the pegs where it is needed. I find it beneficial to keep my right foot forward on the peg where I can retain control over the rear brake at all times and I shift my left foot further back riding on the ball of my foot, the staggered stance offers better front to rear balance control. Setup of the lever and bar position is critical to keeping only your index fingers on the control levers at all times and that will help you to control everything that needs to happen when you are popping a wheelie or riding a cat walk. (cat walk is the term I use to describe a sustained wheelie or when you ride only the rear wheel like a unicycle.) A taller gear selection and using front to rear balance point control instead of the engine power will address the over-rev issue.

Absolutely time to revisit the carburetor and if this is a carburetor where you can put the slide in rotated 180 degrees from where it should be, that is very likely the problem. Should take all of 5 minutes to check that.

Get compression test done? 🤔 It's a 2-stroke, pull the spark plug, remove the kill switch magnet so you don't get a shock, plug the spark plug hole with your finger or thumb and turn the engine over slowly. Spark is useless if it happens at the wrong time, once you know it has compression check your ignition timing or you can't rule out ignition as being the issue. What is the recent history of the bike, is it fresh out of storage or was it running and then failed?

Something tells me when the carburetor acts up you will know why the spring is in there.

Trouble-shooting section of the service manual will give you all the same questions we could possibly ask.