konrad

Sorry, no clue. The clean pilot just look like a modern Keihin. I'd advise sending pics to your next vendor to make sure it's what you need. Maybe you can find a part number here: https://www.cmsnl.com/

Maybe the finger just got tired? Human evaluations are subjective. I've used a fish-weighing scale to quantify how much force it takes to pull a lever.

Don't shove the wrong pilot jet in! Yes, that is a limiting cap that was introduced for EPA compliance. Reading a plug is a skill that can't be taught -- only gained through much experience and experimentation. Rather than bother about how the plug looks, concentrate on how the bike performs. Don't be afraid to experiment! I like to have at least one jet either side of standard to know in which direction to go.

Some water pumps have a drain screw. Otherwise, you’ll have to temporarily remove a hose. You may need to tip the bike to get out as much old coolant as possible. Refill so the tops of the radiator tubes are just covered. Run the bike for 30 seconds to see if any air was trapped in the system. Refill if necessary. Since there is no coolant recovery tank, any excess (due to thermal expansion) will just flow out the overflow hose. This is the correct level.

I agree with Lemur. But if you insist, I can highly recommend Splatshop. They are second to none in terms of price, convenience, and support. But shipping oils by air will likely cause a problem. The US Postal Service allows a small volume of oil to be sent by mail, but only when using the special precautions shown below.

The TXT321 was my first trials bike. I have a vague recollection that the pressure plate requires a specific orientation. Found the following pic in my notes on the bike. Note alignment marks. Also, I always short-filled the gearbox (using 450 - 500 ml) to reduce clutch drag. Discovered that on my own, but later learned it was the factory-approved fix.

In lieu of a mechanics' stethoscope, I've used a length of hose to track down the source of noises. Run the bike on a stand. Since you needed to replace the chain, it's probably time to lube the suspension pivots.

Your circled part is the old version of the silver part in your photo. Had the jumper wire caused the fan to run, it would have showed that the thermos-switch (thermostat) was defective. Time to take it to the bikes shop. Konrad out.

What you have circled is for an older model bike. Fun Module is a misprint. It should say Fan Module. The thermostat should actually be called a thermo-switch. It is electrically open when the engine is cool. It closes to turn the fan on when the engine requires cooling. Connect a jumper wire between the two terminals in the photo I have cropped. At this point you may need to enlist someone locally who has some electrical knowledge to help.

Nope. That's an unusual combination CDI and high-tension coil. Silver box is the rectifier/regulator.

Substitute the thermostat (switch that is in the radiator) with a piece of wire while the engine is running. The fan should run. You can test for DC voltage between the wire leading into the thermostat and chassis ground with a multimeter or a 12V light bulb. BTW, the alternator comprises the flywheel and stator plate behind the flywheel. The yellow wire from the stator provides power for the fan. The stator emits AC and the regulator changes it to DC and and limits the voltage.

You can test the fan itself by applying 12 VDC directly to it from a battery. Fan motors often fail if the bike gets pressure washed carelessly.

Yes, it's repackable and you must drill out the rivets. Oil is a bit like religion, and you will get all manner of answers. A white paper by Maxima indicated that small cylinders require a greater proportion of oil than do larger cylinders. The reasoning is that they are being worked harder and revved higher. But if you are not using the engine to its full potential, it's possible to have too much oil. It's entirely possible the carb is jetted too rich and that is exacerbating the problem. I have found that the needle jet tends to wear oval over time and this causes rich running. Before tuning leaner, I recommend replacing the needle jet. You should also clean the entire exhaust system. Without doing that, you may not realize when things are right because it will keep oozing old unburned oil.

Also, using K-Scan you can globally enrich the mixture (up to 15%). The will help cooling, but also will tend to soften the performance (which might be a good thing for a Factory being ridden as an Explorer). Globally enriching the mixture will also decrease range by a corresponding percentage.

The TXT also lacks the Pro's diaphragm clutch and patented "4 gear-pairs provide 6 ratios" gearbox.

The radiator is in an atypical place on the OSSA. I suspect the fan can't push as much air through it as if it were hanging out in the breeze like a conventional trials bike. I'd be curious what 2 maps are in your bike. As far as I know there never was a hard/soft map combination. Here is a list of the final .KDA maps produced: https://www.ossa-efi.com/home/pc-software/map-loading-software K-Scan will tell you what map is in the ECU, but won't change it.

There must always (when hot and cold) be a small amount of free play there.

What's the best lube for a gearbox? Gear oil. What's the best lube for clutch plates? ATF. Pick what you want to optimize. Electric Motion got it right with the FACTOR-e, They used two different lubricants in two different systems. The gearbox lube is separate from the clutch lube.

Do you have the dual map capability? There were specific richer maps for road use. Pure water has the best heat transfer properties. The more antifreeze in the cooling water, the worse the heat transfer becomes. Of course, no antifreeze means you lose boil-over and corrosion protection. I have used a product called MoCool by Motul in roadracers where antifreeze is prohibited: https://www.motul.com/lv/en/products/mocool

Your clutch is not disengaging. Possibly a problem with the clutch master cylinder (handlebar lever). Is it leaking? You may need to install a new "clutch pump piston". At the very least, give it fresh mineral oil and bleed any air out of the clutch hydraulic system. I added part numbers for the clutch pump rebuild kits here: https://www.ossa-efi.com/home/engine/clutch#h.sf023em3dqtp Definitely change the gearbox fluid as well. Use any ATF that's available where you live. I would ride the bike for 1 hour and then change the gearbox fluid again. 7 years is a long time, regardless of hours. Inspect the drain plug magnet for metal particles.

At first, I thought 50 km/h was expecting a bit much from a kid's trials bike, but that is realistic from a test I just read. Although I have no experience with the 20.0R, I also just read that it has separate adjustments for power and speed. I would investigate the "speed" dial. Is it adjusted for max speed and not defective? You mentioned technique training. I take it your son is not riding it as a trials bike because 21 km/h would be more than enough for backyard trials practice.

The GG manual may be a typo. But if I had to guess, I would say the published spec may be the torque use by Morad's wheel building machine (likely with a lubricant on the thread). It has no bearing on tensioning a dirty spoke by the end user. This test shows the effect of torque on a lubricated thread versus a dry thread: https://youtu.be/-hSmtLVESSM?t=999 The link drops you into the relevant part, but the entire video is worth watching.

After seeing those spoke torque specs written in newton-meters, I agree they do seem low. As a very general point of reference, a standard M4 fastener might require 3.5 Nm, and an M5 fastener about 7 - 8 Nm.

Will it restart easily immediately after a hot shutdown? That would be a clue whether heat-soaking is the issue. Is this bike new to you, or is it a new problem? Could be something as simple as using "winter" vapor-pressure gasoline in the summer.

So it's difficult to start only when the ambient temperate is high? How does it start when the engine itself is hot? Have you checked the valve clearances?