lemur

Schematic indicates non regulated to the lights and horn and the regulator is on there for the fan only, the capacitor is on there to make the fan motor work better. All that runs off the lighting or accessory coil which is independent of the ignition coil.

CV carburetor running lean, just like CV carbs were designed to do. You might try raising the needle if the problem happens at greater throttle opening. What does the spark plug look like? & does it smoke at the exhaust &/or is the engine full of carbon ?

Horns draw a considerable amount of power, even more when they get old and rusty or full of water. ~30 watts is typical, the 4RT has a significant large alternator on board to accommodate the fuel pump and fan, the alternator windings are oil cooled which works brilliantly if you should be stressing the limits. Conserving power consumption from other accessories such as the high beam and horn leaves that power for your little heat strips. I would be way more concerned about cooking the stator by running heaters on my TRS. I don't winter ride the lakes much I ride the same back woods trails we ride the rest of the year, way more fun . Competition soft compound tires can't withstand much below single digit minus centigrade temperatures and a heated garage with the riding area right outside my door makes it possible, caution that at minus 22C riding the knobs will peal right off your rear tire. Stored in extreme cold trials tires crack the sidewalls if you leave the bike sitting on them at low pressure. When you are running 1740 GripStuds in subzero temps on ice and snow it is advisable to run higher then normal low tire pressures so that the sidewalls don't crack so badly, 👍 studded trials tires are awesome fun and extend the riding season by months here. Since running studded tires I even look forward to winter riding 😎

One problem you might encounter with the 4RT in winter is sub-zero engine starting as I did, if your engine oil gets too cold it will make cold starting difficult to impossible. I even tested 0W winter grade engine oil but had no success with that. Be ready to build a small fire under your bike to sub-zero cold start it.

Better control over the operating temperature sounds like a very good idea, I have the heated grips on a little snowmobile and find the heat too intense to operate continuously and need to toggle the heaters on and off to reduce the intensity to a tolerable rate. When I winter ride my trials bike it is the clutch lever finger that freezes first and has me pausing regularly to warm my fingers on the engine, the grip heaters do little to address that. Hotshots chemical heat packs inserted into the back of your regular riding gloves work as an alternative to the grip heaters, but similarly do little to warm the lever fingers. I have heard of local riders using the electric heaters on the control levers instead of the grips, but have not personally attempted that yet.

Roughly the same power as your horn. 🤓 Don't use the horn at the same time as your heated grips and there should be no issue.

Why don't you just re-anodize the original aluminum rims 🤔 there are lots of companies that specialize in aluminum anodizing.

I have a 2021 and a 2023 the replacement spring was difficult to install and broke within a very short time, then I went for the extension type spring as a more reliable alternative and I can source them at a hardware store, so I figure why not just set it up for that type of spring. If there is no spring the bike does not roll backwards and the tensioner arm binds up.

If we want to get all scientific there a 4 types of stainless steel and it is the chromium content that largely alters the magnetic attraction of the steel and the possibility of nickel added which has a grain that does not make a good magnet, all steel contains iron. The problem with the replacement spring in question is, they bent it in the wrong place.

Yep, I bought one of those too, it's not bent correctly, ended up sourcing a package of regular assorted coil springs from a hardware store and improvising something that works as good or better to the original.

No spark happens at the pickup coil, it's just a coil that briefly produces a small electric charge that in all reasonable logic goes to a little black box ignition control module just like a regular motorcycle, that in turn sends an amplified charge to the secondary coil producing the spark at the spark plug. I'll bet everything to do with the fuel injection is just like any other electric pump fuel injection system and everything to do with the modern 2-stroke motor making a spark at the spark plug is just like every other modern 2-stroke motorcycle that makes a spark at the spark plug. ... You do have 2 small black boxes, one is going to be dedicated to the Fi and one is going to be the ignition, odds are nobody short of the original manufacturer knows what is inside them which might be Hitachi or some such company.

I use an oscilloscope to test the AC outputs, nothing beats that, your pickup coil should ohm meter test easy and be adjusted (if possible) for the closest proximity to the magnets to optimize performance, pickup is simply a field coil that initiates the spark and provides timing for the fuel injection.

imho an upgrade would be to keep the small battery and add a capacitor and if it is only a cold start problem install a jumper port where you can easy plug in a small power supply.

If there is no spark start by checking the stator windings and ignition pickup outputs, your spark plug does not use the capacitor to make a spark. ... interesting that one would consider a capacitor to be an upgrade to a battery 🤔 if I was building fuel injected motorcycles I would think a capacitor in place of a battery would be a cost and possibly weight saving measure, not a performance improvement. Both are power storage devices but a battery maintains an electric charge for a considerable time where a capacitor retains a charge until it is discharged and then it becomes basically flat or dead. The cap won't charge until you start cranking the kickstarter, a battery in theory would be ready to provide full power right from the first kick.

Generally the capacitor is not a tremendously expensive or special part and worth stocking a spare to test or replace, the primary reason it is on there is because your bike is fuel injected and Fi needs DC power in the form of a battery and or capacitor to supply sufficient electrical power to the DC fuel pump. Symptom of a failed cap on your ride would be lack of fuel pressure not lack of spark.