konrad

You are absolutely right, it was the pump test I used to drain the tank. Just ran the injector test on equipment in my lab. That test generates five approximately 100-microsecond pulses, 1 second apart. So yeah, that is not going to squirt any fuel! I think maybe they did it that way so it would not flood the engine? It's more of a test for the design engineer than the repair technician. Thanks for making me take a look at it.

Something weird going on there. I have used the injector pump test to drain the fuel tank: https://www.ossa-efi.com/home/chassis/fuel-pump#h.aueu7tpf4lup

EVERYTHING in a carb needs fettling.

The specs for a 2003 290 with PHBL26BS carb are: fuel screw 3.5 turns out from lightly seated. Clip 3rd groove from top. The idle screw should allow the slide to be "a little bit open." Very roughly, you want to be able to get a 2 - 3mm wire to pass under the slide. But this is all just a starting point. The local fuel, premix ratio, atmospheric condition, cleanliness of air filter, and rider preference all play a part. BTW the standard pilot jet is a 33. This jet must be perfectly clean! (And it's the thing that gives most people trouble.)

Is that a Beta Explorer? How far can you go on a charge?

For your testing: ECU pin 4 is the high side (+12V) for the injector. The low side (switched ground) of the injector is ECU pin 18. There is a small pilot current (89 uA) running through the injector when it is shut. This allows the ECU to verify the injector is electrically okay. On the dead ECU I reverse-engineered, I found the IC that deals with this pilot current was fried. I hope that is not the case with your bike! One possible troubleshooting technique would be to power the injector directly from a 12V source instead of via ECU pin 4. ECU pin 4 wire color is pink. ECU pin 18 wire color is white with a green stripe.

You have fuel pressure and can hear the injector clicking. Doesn't that mean the injector is clogged? I would not expect to learn much by putting a voltmeter across the injector. The duty cycle is quite short. You'd need to use an oscilloscope.

Seems like that should solve the problem. I did not suggest that as a solution because it seems most vintage riders would prefer to clutch as little as possible. When I transitioned from a 2T to a 4T, I basically pulled in the clutch whenever beginning to decelerate. Then I'd slip the clutch until I got the "correct" amount of engine braking for the situation. Now with an electric trials bike, it's exactly the opposite problem. So I have engineered-in a small amount of automatic regeneration on closed throttle.

Now you've got me curious! What is it?

Altering the chassis geometry can help accomplish your goal. Lowering the front and/or raising the rear will make the bike turn tighter with both wheels on the ground. This will help prevent the front from "pushing" too. But, it's all a compromise and the radical changes will negatively impact other aspects of the bike's operation -- like how easily it wheelies and the amount of ground clearance it has.

I think taller gearing would be better than shorter gearing. Prove this to yourself by putting the bike on a stand in 1st gear. Attempt to turn the engine over by turning the rear wheel. Pretty difficult, right? Now, try the same thing in top gear. MUCH easier. Another thing would be to set the idle speed higher.

I don't know anything about the Oset 20 Lite, but this source https://www.ultimatespecs.com/motorcycles-specs/oset/oset-200-lite-2017 says it has a maximum power output of 0.9 kW. Your lithium-ion battery is rated 42V and 160A, which would permit a maximum power output of 6.7kW! Even when the battery is depleted to 36V, it's capable of providing 5.7 kW. Electric vehicles are a system comprising motor, battery, and controller all designed to work together. Your controller is protecting the system from that very powerful battery by temporarily shutting off. Basically, your Li-Ion battery has "upset the balance of power."

Parts book and service manual I found online are for slightly earlier models. It's possible your 2024 is different.

There are many ways to test a capacitor, but if you don't already know how, you probably don't have the proper instruments. In that case, substitution of a know-good part is the best method. eBay is probably the easiest (not necessary best) place to buy capacitors. A prior post said, 4700uF @ 25VDC. But I have no idea if that is correct. Whatever the value is, it should be rated for 105 degrees C. Look for a capacitor specified as having "low ESR", or better yet one that specifically says it's capable of withstanding high ripple current. Some capacitors made in China are okay, but unless you have experience with a particular manufacturer/vendor, I would suggest buying a capacitor made in Japan. If you buy Chinese, buy several to have as spares.

The service manual I linked shows different wiring diagrams for the 2ED (street) and 4ED (competition) version. The only handlebar controls on the competition version are the map switch and tether kill switch. That's all you need to make the bike run.

Honda makes the best service manuals in the world! This is for a 2020 model 301: https://www.montesa.com/wp-content/uploads/2020/03/OSM-301RR-2020-EN-Web_V04.pdf Look for "Cable & Harness Routing" .PDF page 36 (manual page 2-13) shows the rear harness. Seems easy to remove. I did not see anything specifically about the 2ED front harness, but it may there too.

+1 When I would take newbies trials riding, they always asked about boots. I would recommend any boots (hiking boots, combat boots, even road racing boots) before MX boots. One local motorcycle accessory shop found that although it was not worth stocking Gaerne trials boots for trials riders (not enough of them), it was for adventure riders. I like my Gaernes for building sections. I prefer the stiffer Alpinestars Tech Ts for actual riding. It's really important to try on any boot you are considering, as there is no size consistency among manufacturers. And I've even found a "pair" of boots that felt like totally different sizes.

It's your bike, but if you look at the chart, 45 to 46 centistokes is a 10 wt or 15 wt (depending on manufacturer). You really cannot judge how the old oil performed because it is contaminated with debris. Usually I think of oil losing viscosity as it shears down during use. But it's equally likely the viscosity increased due to the presence of debris. You really need to get a baseline by starting with a clean, known oil. The clickers (if any) can't fix the problem alone.

The data sheet for that oil says it has a kinematic viscosity of 45 mm^2 / second at 40* C. mm^2 / second is the same as centistokes (cSt). I always compare oils by their kinematic viscosity because there is considerable variation in how manufactures grade their oils. Peter Verdon posted a fabulous table years ago that I can no longer find. Fortunately, someone copied and reposted it here: https://norwestsuspension.com/suspension-fluid-viscosity-chart Look at the 40* C specification. As you can see, there are several oils that meet the viscosity requirement. Mostly, it depends on what is available locally. I wrote the follow specifically about 40mm Marzocchis, but there is generally applicable tuning information: https://www.ossa-efi.com/home/chassis/marzocchi-forks And BTW, 140kg is totally off the charts. You are going to require one hell of a stiff spring (front and rear) to get the sag anywhere near correct.

You already know what to do. Get K-Scan again and see what historical errors are stored in the ECU.

Although jetting has an effect on rate of combustion, that's not what causes kickbacks. When a kickback occurs, the force from combustion pressure exceeded the force from flywheel inertia. Basically, the combustion pressure was high enough (too much burning too early) before TDC (rather than after TDC) to cause the piston to turn the crank backwards. Ignition timing for starting is retarded from normal running for this reason. It's possible the stator plate is too far advanced. Or it's possible the ignition system is intermittently behaving badly. Do you have a timing light, a helper, and a dark place to work? If so, you can see it the ignition timing is different from normal when a kickback occurs.

The trials bike looks heavy. Although I am heartened to see a gear-change lever. I feel having a gearbox is the way forward for electric trials bikes. I have mixed feelings about the conventional clutch. I liked it on my 4RT as it was zero-maintenance and had a fine feel. But a small diaphragm clutch is much lighter. To me, the motocross bike looks better suited to its intended purpose. And, like the Stark Varg, the MX bike has no gearbox.

I knew I had seen something like that before, and kept thinking antique board-track racer (which was not right). You can clearly see from the photo it's just a cut-and-welded standard bar -- not even a custom bend.

I downloaded a large version of the JPG. You can clearly see a gear-change lever!

When a DC motor starts, it draws several times its normal running current for a fraction of a second. What's worse, frequent starts or constant running? Depends on the duty-cycle I suppose. Either way, I would not lose sleep over it. The thing that kills fan motors is hitting them with a blast from a pressure washer. If only there were some type of automatic control to turn the fan on and off... 😛