lemur

👍 In vintage events we use to call them cheater bikes because they could do so much more compared to a 70's TY or Bultaco etc. Gearbox oil is nothing special, as with any the more frequent you change out the clutch/transmission oil the better. For premix I would run full synthetic at lean ratio to keep the exhaust clean. Rotary valve 2-strokes are extremely powerful and about the most common way to destroy one is to not keep the intake air clean, or to over-rev the engine. You don't know what you are missing by not riding in winter ⛄ studded tires are a game changer and can extend your riding season to 10 months of the year 😎

Sparkplugs are designed to fit the cylinder head, long thread plugs are more typical on heads where they need to get past valves. You have the unknown aftermarket cylinder head in hand to measure, we don't. If you want to be rude, end of trying to help the likes,

Normal reach, long reach 🤔 no such thing unless there was only 2 spark plug ever made.

Apologies, opened his post to see what you are working with, strange way to do it. I like the stock compression, not even sure why you would want to lower it, best luck with your mod. ... I would have stuck it in my lathe and shortened the collar, looks like it has a ton of thread engagement, but we can't see what you guys can with one in hand.

If the head needs a longer reach plug that should be easy to measure.

Local hardware store, it's a chainsaw sparkplug. Cheap and easy to source.

Must be why they make 27.5mm hex socket wrenches 🤔

The drain in the bottom of the air box is not the greatest design if you ride deep mud lots they tend to fail.

The thing you don't want is friction modifiers, only use oil or if you must ATF that is designed to work on wet clutch applications suited to the plates you are running be that cork, paper or carbon fibre. The transmission is non filtered so the best oil is the one you are likely to change most often.

Cog it up one or two gears, use the clutch more and fully extend your arms 👍 1st. gear is geared so low there will always be tons of engine braking.

Sounds like you are riding in first gear, 300RR will pull 3rd. Montesa has a slightly more settled suspension compared to the Beta, not as lively suspension but the engine performance should never be lacking.

Tax on trials bike sales sounds like a good way to make hundreds and hundreds of dollars lol

Apparently China doesn't have the engineering or they would not be buying it.

They should start building electric motorcycles in some economically depressed first world country where the domestic currency is only worth 69 cents on the US$

Correct answer is Papa if you can possibly swing it buy a 4RT, it's a current production model bike and infinitely superior bike to own, ride and maintain.

TL lol you should have made it a poll

Looks like a lighter duty bearing compared to what my trials bikes use. In my experience if bearings fly to pieces on removal that is usually because they were left too long before being replaced.

Just a guess that MOT inspection guy will not be able to check the chain guard is secure if it does not have a chain guard.

It's called homologation and if it hasn't come to your country yet it surely will. Third world countries might never adopt it, by our laws you bought a pit bike, perfect for use on private property use or closed course competition where it exists.

Guessing you don't have access to electrical test equipment. If testing involves shipping in both directions or they just say it is faulty on receipt, it is generally best to just buy a new part. If your bike has no black box to control the ignition that means the coil and associated electrics will be even easier to meter test. Best luck with your repair 👍

Today 😎

And you would be correct, you are looking at the coil pickup or signal generator to control spark, that pickup generates a small charge of electricity when the magnets pass by it, that electric charge goes to your ignition control module where it will be used to send a whole bunch more electricity towards the ignition coil and spark plug. Coils have measurable resistance unless they are burned or shorted, then they will show the wrong resistance or no resistance at all aka no continuity. You can meter test the coils, meter test the connections and wires, you can meter test the power outputs once you have it somewhat running, but that part #4 the ignition control module is going to be by far you biggest problem to test or replace.

Lots of rectifiers or regulators would work, those are about the least 'special' parts in the whole electric system, everything else is more difficult to substitute and unique to fit the model.

Do you have a VOM (volt ohm meter) if you do then test for resistance (ohms) between the yellow wire coming out of the alternator and ground. Have you removed the flywheel yet? ... a photo of what is inside there would be helpful, we are looking for breaker points or a magnetic pickup to control when the spark happens.