konrad

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?

The OSSA version of K-Scan will not work with GasGas - despite them both being Kokusan Denki ECUs.

I considered buying a spoke torque wrench when building some supermoto wheels a decade ago but decided it was unnecessary. Although torquing may make sense for brand-new spokes, by the time the threads see any mud, water or just dirt, tightening torque no longer has much relationship to tension. And proper tension is the thing you are trying to achieve. Tension does have a relationship to the sound the spoke makes when you hit it. Ducati even decided that sound was the best indicator of cam belt tension.

I assume they are Morad rims. You could try to contact them directly https://www.moradsa.com/ and ask for torque specs.

A bike that new should not need this trick, but in addition to lemur's penetrating oil, particularly nasty ones need heat. I generally give the nipple a quick blast with a propane torch. I always make sure I can loosen a nipple prior to attempting tightening. You can tell a lot just by sound. Try tapping each spoke with a light tool (screwdriver, spoke wrench, etc.). Tight spokes will ring. Loose ones with thud. You want them all to sound similar. I don't own a spoke torque wrench.

The nominal size for a flywheel puller will almost always be a whole number (e.g., 26, 27, 28, 30 mm, etc.). Like all fasteners, a flywheel puller is measured on the OD of the male thread. A 30 mm puller will measure about 29.8 mm (slightly smaller to allow clearance). Presumably, you are measuring the ID of the flywheel (female thread). Adding the thread's pitch (e.g. 1.0, 1.25, 1.5, 1.75 mm, etc.) to the ID you will get close to the OD. Lacking a thread pitch gauge, you can compare bolts of various known thread pitches to your flywheel. You will need good light and possibly magnification to make an exact match.

The hex nut that's screwed into the flywheel looks like an adapter for a common bolt. If you remove the hex nut, what does the flywheel itself measure? Most of my pullers are in the M25 to M28 range. 1.0 and 1.5 are the common thread pitches.

I've made a number of throttle cables from scratch using bicycle brake cable and homemade brass ends attached by soldering. It's easiest to start with something close and modify it. In the States, Flanders sells a variety of stuff to build your own cables: https://www.flanderscompany.com/collections/cable-parts

Don't know how desperate/adventurous you are, but some Ducati Energia stuff appears to have been cloned in India. Here are two examples: https://www.ebay.com/itm/195766384472 https://www.ebay.com/itm/384465870455

How do you know? There is no "R" in the size description for the front. Yes, the bullet point says "Radial construction" but I think that only applies to the rear.

Lemur, do you actually have a Michelin front that's a radial? I don't. https://www.denniskirk.com/michelin/trial-trial-x-light-tire.pfp643430.prdf?fs=643430&rs=643431

Are any front trials tires radial construction? Appears the Dunlop D803GP has been discontinued and is being replaced by the Geomax.

Just found this pic on dritbiketest.com and circled the area in red.

The person to ask is Lotus54. My guess is that the Explorer tank somehow drains into the M10 x 1.0 port on the right side of the standard tank. There is a pic of a fuel level gauge I made shown here: https://www.ossa-efi.com/home/my-upgrades/minor-modifications It used the aforementioned M10 x 1.0 port.

Part number for the Easy Start system is 1160030214. There were at least two different versions of the printed circuit board manufactured, but the changes were nothing a typical rider would care about. More information here: https://www.ossa-efi.com/home/electrics/easy-start P.S.That's cool to convert the trials model into an Explorer as you'll have the superior suspension components.

Well that is pretty cool. I Googled "chapman bsa trials" and the first hit is here: Looks like the original builder was a member here (mick_99) and replied, "...20 production bikes and there were 3 prototype made:..."

Although this information is for North America https://en.wikipedia.org/wiki/Vehicle_identification_number many European manufacturers use the 10th character in the same way. So M would be 1991 or 2021. Does that seem reasonable for the bike?

That monoshock configuration is reminiscent of mid-1970s Yamaha MX bikes. Some interesting backstory here: https://motocrossactionmag.com/classic-motocross-iron-1974-yamaha-yz360b-monoshock/

The first time I used the steam cleaning trick was with the bike running on a stand while strapped to the trailer. It was the rear, and I just applied brake pressure while the wheel was turning. I could easily monitor the rotor temperature with an IR thermometer (which is totally unnecessary). Get the rotor so hot you can smell the pads cooking. More than one application may be helpful.

Thought of another thing I will add for completeness. Pure water has the best heat transfer properties, but we typically use antifreeze for a variety of reasons. A 50/50 mix of ethylene glycol / water has very good heat transfer properties. Pure ethylene glycol has quite bad heat transfer properties and why it's not used above 70% concentration. Straight ethylene glycol as coolant would definitely cause the fan to run much sooner than normal.

The exhaust system of all 4-strokes runs much hotter than 2-strokes. I did very few mods to my 4RT, but one was applying “header wrap” to the exhaust system between the heat shield and muffler to prevent melting nylon riding pants. As suggested, checking the oil and coolant levels is a good idea. Also check for a blockage in the radiator: mud, collapsed fins, etc. How soon the fan turns on depends on engine load and airflow through the rad. For a given ambient temperature, high load and slow ground speed turns the fan on quicker than light load and a lot of airflow. The bike is new to you, but how new is the bike? Due to friction, the entire engine will dissipate more heat during the break-in period than afterwards. Scariest of all, it's possible you may have a mis-drilled oiling system. See: https://www.trialscentral.com/forums/topic/78761-montesa-4-ride-oil-filtration-issues/

Igor, I don't think the selling price of my bike is relevant and that's why I did not mention it. A long list of modifications, spare parts (and the promise of technical support) was part of the sale. Local market conditions play a huge role in price -- look for comparables where you live. Condition has an even greater effect on price. The bike looks clean, but as a wise man one said, the cheapest restoration you can do is with a camera. Is the shock leaking, does it need crank bearings, etc.? When was the last fork service performed? Does the clutch operate properly? How old are the tires? In the end, it's worth what you and the seller agree it's worth.

I had that exact bike in my stable until just a month ago. Although called a 200, it actually displaces 163cc. It exhibits all the desirable characteristics of a 125, with just a bit more torque. It is the most beginner-friendly reliable trials bike I could imagine, and super-easy to start. It's the one trials bike I said I would "never sell" because it was perfect to introduce anyone to the sport of trials. But alas, I ran out of newbie friends and space. The only possible downside is the ignition system. My 2003 had the bulletproof Ducati Energia system. Slightly later models used a vastly less reliable Leonelli system. Follow this link to see a picture of the two flywheels side by side: https://www.electricmotiontech.com/home/what-makes-a-good-trials-motor/flywheel-inertia The Ducati is marked 200, the Leonelli is marked 125.

So true! To the OP, it's often difficult to tell the difference between an electrical misfire and a fueling misfire. I'd richen the jet needle clip to see if you can move the misfire to a differed throttle position.