lemur

Sounds like a standard part if the bike was being sold to somebody with a license restriction and the intention to plate it as such. Pull that out and you will have a lot more power.

Your TrumpTax just did impact you, before this era I would have just mailed you the spare parts for free and ate the postage, now I don't want to.

What if I give him a 4000% discount 🤔

Poor fella lives in the USA the tariffs he would need to pay would be astronomical and impossible to calculate.

I owned 3 Montesa bikes at the same time, a 250, a 260 and a 300. I swapped out parts assemblies between all of them to trouble-shoot issues at one point and I found that absolutely everything was interchangeable without causing issues.

Stainless steel and the same size as my size 8 wedding ring. Too bad you don't reside in Canada I have all that stuff sitting in my spare parts drawer, if you lived local I'd give it all to you to mess with. I think altering the fuel mapping on the 4RT would be a complete waste of effort considering the stock fuel mapping does not need to be changed when you remove all the mechanical intake and exhaust restrictors, it sorts itself out just fine. The fuel injection works great corked or uncorked, they just have less power response when they are corked so why would you want to mess with the fuel to air ratios. I had one 4RT with the 2 position map switch and left it in high or dry power setting all the time, same as with my TRS machines more power is better, I think all the map switch changes is to slightly alter the ignition timing, like an ignition advance.

See the tailpiece part # 23 and see the tailpiece that it replacers with rivets, I have one of those as spare and I bet lots of other do too. The rest of the restrictors are simple to make on a lathe if you don't want to source them as original Honda parts.

In the Montesa 4RT parts manual. There are different versions of the muffler and tailpiece depending on what year and model you are working with, any dealer or customer that has done a competition prep on a homologated 4RT will have the restrictor parts. There is also an intake restrictor plate but you don't want those installed unless you want to completely disable about half the bikes normal power. ... the exhaust restrictors are all 18mm inside diameter.

There are an assortment of restrictors available to detune the 4RT all the way down to ~125cc performance ( learner license ). one plate goes into the intake and 3 are available for the exhaust including a different tailpiece that can be riveted on the tail end of the muffler. ... if you really want to detune one it's not hard, the fuel injection will even sort itself for everything except idle screw setting.

Pure theory dictates you should use the correct spark plug, wire and cap 👍 So did that fix it? ...short plug in a deep hole in a 2-stroke might well run like a plug that is 12 ranges too cold depending on what wrong plug was installed.

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

Dragonfly is 21Kg lighter and I can tell you that TRS electric start is high maintenance, it would work better if you kickstart her TRS bike when it is cold for her if you go that way, the electric works best on a warm engine.

Dragonfly 👍

Reach implies arm position so height and position of your bars is where you would adjust for reach, a set of taller bars aka 'indoor bars' is a good investment and will fit both bikes, had them on one of 2 rides and it makes a surprising difference in leverage and riding position.

So you are scratching up your fresh new spray coat of ultra hard nickel and silicon carbide that is actually harder then your piston rings for what purpose 🤔

When a piston ring pack becomes gummed up from bad fuel the rings stick in the piston grooves, then everything starts to go badly. Once you experience it you will know why I call it a jam sandwich.

In theory; your piston wobbled because of either tightness in the wrist pin bearing or a jam sandwich in the piston rings.

Just push your bike home, bump start it, or call a tow vehicle 🤣 says the 200 pounder who only rides flatlands and quad trails.

You sure you want to hone a plated barrel 🤔 don't think you are suppose to do that.

If you plan to ride in cold climates the first thing you will want to add is a jump start port so you can carry some extra battery power, e-start on my TRS bikes is very seasonal. If it has a sprag bearing in the starter you might even want to pack a spare motorcycle.

Oil won't hurt the throttle body. The fuel injector is after the throttle body and that is where fuel residue would start to be apparent, if anywhere. Race fuel is a very aggressive solvent if you have been running poor quality fuels and will be going through the injectors. Crankcase ventilation is critical to preventing oil going places it should not, like past the intake valve seals for example. Spray solvent can dissolve the blue silicon insulation inside the main electrical connector, use only air if it gets water condensation in it. If any flame gets past the 4-stroke valves the filter could ignite unlike the 2-stroke 315 model, hence the addition of a flame screen is required. .

I think you can get a clear float bowl for that carb, makes it easier to diagnose 🤓

It's a radial rear and it's stamped for 'trials competition use only' right on the sidewall, I'm guessing it's a trials tire worth a try. It's not like a rear tire lasts any longer than one season anyway. + If they are any good you can bet the price will increase.

The cap is on there to make the fuel pump work better. The cap is small compared to the one on a Montesa, personally I think I would double up on the cap, that would be cheap and easy, might even give immediate results if the cap on it is lacking.