lemur

How much do you figure has changed? We are talking about trouble-shooting one of the most simple electrical systems in existence. If you were ordering parts it might make a difference but a thermostat control on a fan is as basic as it gets, it's just a switch that turns on when you heat a sensor, if you don't trust the thermostat you can bypass it with a toggle switch. If bypassing the switch doesn't work then he has a problem with power generation and the test procedure for an alternator, rectifier and regulator is unchanged.

Search harder -> https://www.mrsltd.co.uk/Catalogue/Sherco-Manuals-Parts-Books/Manuals/Trials

Service manual shows the fan is controlled by the CDI unit and they detail how to meter test the thermostat in hot water. On my 315 Cota the fan would kick on in the middle of a section and the idle would drop enough to risk stalling, so I put a bypass toggle switch on the fan circuit and that was handy. Better to have too much air movement then not enough. I always start trouble-shooting electric problems at the source, so meter test of the alternator windings is the best place to start, also detailed in the service manual.

That's a really old thread you are posting to, I would highly recommend you start a new thread and post a photo of the parts you need, and maybe what part of the world you need them in 😎

That's a negative, the key is in there to position the flywheel correctly, without it your ignition timing would be all over the place. For what it's worth the last time I had a 2-stroke coil rewound it cost about 125$cdn.

The decompressor is a little tiny (spring loaded) weight that is built right onto the camshaft. The valve clearance is the only adjustment. It's a one shot decompressor, if it don't work on the first rotation it won't work. It's on there so that the engine can complete 2 rotations of the crankshaft and start the fuel pump pumping. All you are really doing to start the 4RT engine is to spin it up to idle speed, you don't want to jab at the kick starter like a 2-stroke. Once running the engine will lug down well below the idle start speed before it goes Ker-Puck! and flames out. 100LL avgas contains Tetraethyl Lead ☠️ ... curious why the 2022 models would have fuel pump problems after they have gone so many years without significant changes. Absolute best way to trouble-shoot a 4RT problem is to own 2 of them and swap assemblies until you find something that fails.

lol ya, with the ministry of environment

Ignition key no, you can just put a magnet tether kill switch on it. Meter test or even better an oscilloscope will show you what the output is and how regulated it is, what lamp you use will be dependent on that test. LED uses low voltage but are not tolerant to over-voltage so your power needs to be regulated to suit the LED lamps. You would need to add a capacitor to prevent them from flickering because your power output is going to have a relatively low frequency and no battery to smooth the power.

Not very scientific and likely somebody has a better idea but I always tighten them by hand and then hit the wrench with a hammer to see how much more it moves.

Is this what you are dealing with? Resistance test the coil windings and you should see something in the realm of a couple of ohms per coil. The black box will be a rectifier and the steel cased one that says it must be earthed will be the regulator because voltage regulation produces heat and no way do you want to run light emitting diodes unless you like lights that flicker. LED lamps have no latency so at the very least you would need to add a capacitor to smooth the current flow. Guessing this is a 6 volt system. Super easy to run LED lights off a battery that you recharge from a wall outlet or dead loss disposables like a regular flashlight. No wiring diagram really sucks, sure looks like the lighting coil has just been wired to the ignition coil, that would make it a 2 phase alternator and the output would be easy to check using an oscilloscope.

"Before this all started, I was riding one day and when I tried shut off, bike kept running even though the lanyard was disconected. It died after 10 seconds or so." Would not be the first time the lanyard caused all the problems. Yes, the air box normally accumulates a small amount of clean engine oil. Fuel injection sorts itself out when you leave it idle until the fan kicks on. I'd be tempted to set the valve clearances again, you might not have got them right, have a micrometer handy to check your feeler gauges and to get a feel for the correct clearance. There is a little tiny decompressor on the exhaust valve side and it needs to be spot on to work and that is the source of hard starting. I've run higher octane and it does perform better, but they normally run faithful as a Honda on regular octane fuel. My first 4RT was hard on plugs, every one after that has been good on plugs, I never did find the problem with that first one, I sold it soon after I dropped it in the lake.

Running is good 👍 race fuel has a better shelf life if you're going to leave it stand for ages. Fuel filters are super expensive because they want to sell it with a fuel pump included.

Absolutely the idle needs to be set correct and you can't touch the throttle when you kick it over 👍

The engine still runs and doesn't sound like it has a bad main bearing? It would need to be the right hand side because the alternator side contains engine oil. ... I'd be tempted to change the fluids, ride it and see if the engine oil level increases, if not then that's not where it's going.

Super easy to check your fuel pressure and rule that out. Two methods are covered in the service manual, one that requires a gauge and one that requires no special tools. Set your valve clearances, don't just look at them to be close, physically set them precisely as you can. (You need to drop the engine part way to do it and you need a micrometer handy to test your feeler gauges and get a feel for the correct clearance.) Owned 3 4RT's at the same time, one did not start when I was about to begin a competition and I had to use my back-up ride. After that I took parts from the other bikes and swapped absolutely everything physically possible with no joy. Once I determined it was nothing fuel or spark related I set the valves very carefully and precisely as possible and it worked perfect since. Same problem eventually happened with three 4RT's out of the five that I've owned since 2005.

On the last oil change when there was barely any transmission oil at all, was the engine oil level overly high?

Is that the brake with a Brembo symbol on it? You use air? Air compresses, fluid does not. I always just use the hydraulics that are already attached to remove the calliper pistons. Hold back the piston that moves easy with a pair of pliers and the other piston will slowly hydraulic out.

Step one, obtain a service manual, step two test everything the manual tells you to check or inspect, step three tell us what your findings are and we can probably help you interpret the results. Probably best if you start a new thread unless you know for a fact that you have "over-voltage issues". If it is indeed an electric problem that only manifests when hot, I would start with inspection of the alternator coil and see if it looks like burnt toast, or if the coils internal resistance is correct. Electric issues are always best to troubleshoot starting at the source of power and working down stream.

When you have a small volume of oil that has no filtration or water separator, the logical best practice would be to change the oil out frequently. The transmission oil I have been using successfully for decades in dozens of different engines costs about 5 bucks to change and it works great in winter or summer. Suit yourself but no transmission oil that should be changed frequently is worth 24$ per litre, you're paying outrageous money for packaging. If you want to know what is in a packaged chemical product the best place to start is the MSDS (Material Safety Data Sheet) it's the only place they are compelled to be 100% truthful about what they are selling you.

I just checked the price of the transmission oil you are using compared to what I use, says you pay about $24 per litre and I pay $8.10 per litre. That's sick. What's the nearest farm tractor dealer to you? Buy what they run in the hydraulics and transmissions of their big expensive equipment, change it frequently, it will work. ... do not over-fill, that won't work.

Is it still dragging in first gear only and no clutch dragging in second or third gear?

Without even getting to see it, if the damage is limited to the copper then it is serviceable, if it went deeper that's not so good.

Quote from the TRS Owner Manual (same for all displacement models) "This motorcycle uses two-stroke synthetic oil mixed with 1% 98 octane fuel. Do not use any other kind of lubrication without previously checking with an authorised TRS mechanic." Recommending a synthetic oil labeled 100:1 pre mix ratio is not over thinking, that's just reading and applying the instructions correctly.

It's not terrain that will cause your combustion chamber temperatures to be wrong or even engine revs, it's the actual fuel to air ratio. More oxygen = hotter burning so if you run too lean in any range of operation you will see more heat, right up until there is not enough fuel mixed with air to ignite and then you will have fuel residue. If the manual calls for 100:1 oil to fuel and you run 60:1 how much excess oil are you putting through your engine? Something in the range of 40% more oil than the engine can burn.

" thinking maybe the varnish hardened up when the bike cooled and stuck the rings to the barrel?" The rings jam up in the piston grooves and then the ring no longer follows the shape of the barrel. That creates a gap between the ring and the barrel where raw fuel and raw oil burns and contributes to more carbon buildup. Carbon is black and that mixes with non-combusted oil to make a glue like residue. A piston and its ring pack needs to operate as an assembly where gasses from compression push the ring more tightly against the cylinder barrel. Look at how a Dykes piston ring works for a better explanation.