lemur

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.

The job of the emulsion tube is to initiate the process of atomizing liquid fuel (and pre-mix lubricant) into the air intake stream, this is the part that makes your float level critical, the top half of the emulsion tube is to remain above the float bowl fuel level and the bottom half of that tube is submerged, emulsion tube is where air bubbles are introduced into the upward fuel flow, iIt will typically have a series of carefully placed tiny holes in the sides of a brass tube to introduce the air and those are the passages most likely to become plugged. If the emulsion tube does not work you get raw fuel or no fuel getting dumped into the carburetor instead of a fine mist spray. The whole assembly is similar to a fly sprayer or a perfume spray bottle or the nozzle on a can of spray paint fed by a toilet tank float valve.

Spring pre-load depends on your rider weight and shock absorption settings are dependent on how lively you want your suspension to react. User adjustable factory settings are normally set to the mid point of the overall operating range so the owner can adjust in either direction to suit the individuals needs. We could probably tell more by watching you ride if your suspension is close, otherwise at this point we don't know how much you weigh, we don't know if the spring rates are stock original, or if your 26 year old fork spring is bagged out. The manual will tell you the minimum service length of the front fork spring to determine when it needs replacement (chapter 2 page 3) , that's where I would start. As a lightweight rider I would normally need to lower the rear spring pre-load and keep shock dampening settings on the low side so that my suspension is more lively, springy, bouncy etc. First question would be are you a light-weight, mid-weight or ample-weight rider. Then I would watch you ride over a log or concrete block a few dozen times to experiment with altered adjustments. Hope that helps some 👍

It says part #27 is the Emulsor for the needle jet. That's the part that will need the most attention.

"almost 2 rounds out" <- sounds much closer to a conventional carburetor setting 👍 if it works there leave it. Pretty sure the low speed adjuster screw on a Dellorto controls fuel and on most other carbs it controls air so you might find adjustment alters the engine opposite to what you might expect. I think as you turn the screw out you are enriching the fuel mixture on a Dellorto. What do they label part #27 & part # 30 on your diagram? Those look more like the emulsion tube that I refer to as being most critical to clean after being subjected to fuel evaporation. Variations on the name 'emulsion tube' are atomizer or pulverizer tube depending on the documentations original language.

So are you 🤣

Poor mans bleed tool:

From what I've seen on my 2021 and 2023 bike, a rubber band or o-ring might even last longer. imo the springs need to become available individually or it's impractical to own them. That's what I will be telling my dealer and ya'll that own one should consider doing the same.

I think the problem is you don't realize how frequently the motorcycle carburetor needs service and once you start breaking parts inside there you are looking at replacement parts or a new carburetor. No it won't matter if the carb is dry or full when you leave it sit because all of the fuel will evaporate out anyway since the float bowl is vented to the atmosphere. There are no 'extra springs' in a carburetor that can be left out without impacting performance. Running more oil in the fuel then called for will result in additional unburnt oil residue clogging up your exhaust system faster. You can physically test a carburetor float bowl valve operation with only the float bowl removed, raise the float with your finger and watch the fuel flow or stop flowing when you lift the float with your finger, it operates on the same principal as a toilet. Taking obvious safety precautions with fuel spill. Idle adjust screw is always the one that pushes the throttle slide higher, low speed fuel or air adjustment screw will be the one 'not' located directly in the middle of the carburetor slide. The adjustment you will likely need to visit most is not the screws which affect only low rev operation but rather the cir-clip position on the main jet needle which adjusts for lean to rich adjustment through 1/3rd to full throttle operation.

After the first lap of section one in the rain here yesterday, mud trashed one steep run-up to the point that nothing was working for anyone, a bucket or two of crushed stone might have made it ridable again, I was very tempted to do roadwork after everybody completed their first loop 😆 but that just didn't seem right so we just crashed there lots instead.

Results are not up yet but the weekend was a blast 👍 bugs were replaced by rain for the main event making it a total $%^&show in section one but everybody seemed to have great fun and that's what counts. Many thanks to all who supported and attended the event, our next provincial round here is July 20-21

Sounds like you need to let about 12 PSI out of your rear tire. The bike with you on it should provide better traction.then when you are walking in your boots.

Rumor has it the spring is the same kind of spring used in oil seals. Now if we can just find a source for those at a bearing supply store instead of a motorcycle shop 👍

How many are rentals?

Importer justifying what they ordered. Why did you order bikes with steel fork stanchions? ... to keep the front end down 🤣 Because somebody is renting a whole bunch of other brand bikes for people to ride?

If the Canadian Trials Initiative was to drop coin to create a CMA sanctioned club in support of a national race series and provide all the things we would require to host events, sign me up. If it's just another obstacle to scheduling, insuring, marshalling and processing the events well 🤨 darn

I don't generally step up to host a national unless nobody else is doing one. Best luck with your Victoria B.C. event, wish I could afford the travel time and several thousands of $ it would cost me to ride it. Hopefully you will see sufficient attendance to substantiate all of the rider classes, very much unlike the last Saskatchewan national where rider participation was pathetic.

The 4RT valves are easy to adjust once you can get to them, you will need to lower the front of the engine to do it easier. It has screw adjusters and not bucket and shims. The screw adjuster head is square and the same size as a red #2 Robertson head screw so you can improvise a tool to adjust the valves with a short stick of wood and a #2 Robertson screw in the end of it. Exhaust valve clearance is most critical because the cam shaft has a very small automatic decompressor built into it and that will stop functioning once the valve clearance is off.

Can't say I ever had any problem replacing the inexpensive oil filter on a Montesa 4RT that can be purchased at any Honda dealer, not sure what people are finding difficult about that. The most complex service you are ever likely to need to do on every one of them is to adjust the valve clearances after about 3 to 5 years of operation. You will know it needs the valves adjusted when one day it becomes hard to impossible to start.

Sounds like the scene in Worlds Fastest Indian where Burt Monro tried adding lead weight to the front of his motorcycle to improve handling. If you haven't seen the movie, the extra weight theory was a fail.