lemur

This is why you should;d always buy trials bikes in pairs, it makes it so easy to trouble-shoot components when you have one that works and one that fails.

Stator should have low resistance as you are seeing, the service manual should indicate the correct resistance. The stator is part of your alternator and should output well in excess of 12 volts AC which is best observed using an oscilloscope. The fan requires the DC 12 volts and imposes the greatest load on your electric system, but for your voltage to drop so significantly with only the fan running I would be inspecting and testing everything from alternator windings, ground connections, rectifier and the fan motor itself.

I use a higher gear range compared to some, apply the revs a little earlier and use the clutch a lot more to moderate the launch acceleration. 4RT power is extremely linear and almost endless compared to the 2-strokes that thrive on short bursts of fast throttle. 4RT also has 5 clutch plates (3 cork & 2 paper) instead of 3 corks like many of the 2T bikes, design theory was to offer better bite.

Blips is a 2-stroke habit and something that the 4RT does not like to do very much, the rider is rewarded through the use of a steady throttle hand.

Curious on the subject of warranty; did the dealer sell you the complete motorcycle in the crate as a competition only race bike, or did they charge you additional for some kind of pre-delivery setup service? At the very least a dealer should warranty their own service work if they charged coin for it. "problems starting in gear." That will always be an issue, the kickstart needs to bring the engine up to the high idle speed to start because you do not have a battery and the auto-decompressor needs to operate at the correct time or the bike simply will not fire up easy.

Strange 🤔 the engine has the ability to pressurize or create a vacuum condition in the bottom end, but the transmission does not. The engine typically creates greater positive pressure during operation from blow by gasses, I would inspect the crankcase ventilation hose, because that pipe needs to vent in both directions and you don't need to take much apart to get to it.

It is a trick question from the aspect that Brembo bought J.Juan which bought Braktek subsequent to their purchase of AJP so yes; there are a whole bunch of different model brakes all made virtually by the same company. Photos are the best way to tell them apart 😕

Over the years there were 2 different sized banjo hose fittings and the handlebar mount went from two bolts to one bolt with a hinge. You will want to make certain your hydraulic fittings are the same or you will end up replacing the entire front brake assembly.

Smaller Condenser 🤔 why? Airbox and drain works great, why mess with it? Remove Bank Angle Sensor 🤔 it's handy if you don't ride with a tether kill switch and the 4RT does not come stock with a tether kill switch.

Those sound like some really bad ideas to me having owned and rode a lot of 4RT' A better heat shield for the header pipe would be good before you melt a bunch of riding pants on it and upgraded foot pegs work better compared to stock.

You have not had the other side apart yet? I bet it has shared oil between the clutch and gears and the first hint is the volume of 900cc (that's a lot) SAE 80 gear oil is plenty heavy on the viscosity.

I'd go by the Yamaha service manual and by my read 0.4mm ring gap is within spec 👍

Lot of riders carry a spare magnet for the tether kill switch. superglue is small to carry and can repair a lot of rear tire splits or punctures.

If you are going to allow the riders to back-up then timed sections start to make sense, it's the best way to avoid what happened in the past where riders took way too long in the sections. imho If the time is too short for a section, somebody built the section too long, lol electric eyes? ...you can buy a sports stopwatch for about 6 bucks.

You're Out! 😄

Riding partner ran one on Beta, reason for the aftermarket alternative was cost saving saving after a crash damaged the original system, sounded different more throaty (lower tone) and altered the power band slightly not to his liking but it was plenty lightweight and the fit was good. It's not something that will make you win trials events or ride any bigger stuff, like say; new tires, wheel bearings, new fork consumables and a year supply of race fuel might.

If it is a Suzuki part that is exactly how it is done, there is an inside thread immediately around the perimeter of the locking nut and that should be visible on close inspection.

If you have heavy equipment or farm tractors and typically have ISO 46 hydraulic oil on hand that works equal or better to ATF.

👍 In vintage events we use to call them cheater bikes because they could do so much more compared to a 70's TY or Bultaco etc. Gearbox oil is nothing special, as with any the more frequent you change out the clutch/transmission oil the better. For premix I would run full synthetic at lean ratio to keep the exhaust clean. Rotary valve 2-strokes are extremely powerful and about the most common way to destroy one is to not keep the intake air clean, or to over-rev the engine. You don't know what you are missing by not riding in winter ⛄ studded tires are a game changer and can extend your riding season to 10 months of the year 😎

Sparkplugs are designed to fit the cylinder head, long thread plugs are more typical on heads where they need to get past valves. You have the unknown aftermarket cylinder head in hand to measure, we don't. If you want to be rude, end of trying to help the likes,

Normal reach, long reach 🤔 no such thing unless there was only 2 spark plug ever made.

Apologies, opened his post to see what you are working with, strange way to do it. I like the stock compression, not even sure why you would want to lower it, best luck with your mod. ... I would have stuck it in my lathe and shortened the collar, looks like it has a ton of thread engagement, but we can't see what you guys can with one in hand.

If the head needs a longer reach plug that should be easy to measure.

Local hardware store, it's a chainsaw sparkplug. Cheap and easy to source.

Must be why they make 27.5mm hex socket wrenches 🤔