lemur

For pre-mix 2-stroke oil it depends on what is available locally. I use to like MC-1 from Belray back in the day because it was the first you could mix 80:1 in a Montesa 360VA remember back in the day gasoline had much higher octane, old bikes were designed to run on period fuels, personally if I was running an old bone bike today it would be on boosted fuel and synthetic mixed as per the manufacturers label. Some brands tend to plug exhaust systems worse then others. For old Bultaco transmission and clutch you are good using all season hydraulic excavator oil ISO 46 which you can buy in quantity from any farm or heavy equipment store, I have used lots of brands and they all perform equally well. New Holland Ambra, Kubota, John Deere, Hyundai It's basically the same thing they use in farm tractor transmissions. Inexpensive enough to can replace it frequently. Farm tractors have everything inside them same a 2-stroke transmission, gears and wet clutch/brakes.

@dunk10 I found a service manual, no oxygen sensor. I recommend you do a fuel pressure test, the Sherco manual shows that you need a pressure gauge to do that and you are looking for 3 bar which is equal to 43.5 psi If you don't have a pressure gauge I know you can also test fuel pumps by measuring the fuel volume output. For example a Montesa fuel pump which operates at similar pressures (33 to 46 psi), when connected to a 12 volt battery the pump will move 0.749 l/min (125 cm3 / 10 seconds)

Do you have a service manual? You described lean operating conditions and the bike is fuel injected. I assume the air filter is clean and correctly oiled with no obstructions, no mouse nest in the air intake. Next suspect would be sensors, starting with an oxygen sensor assuming it has one. Check your fuel pressure because low fuel pressure could be a cause, check the fuel filter itself for damage and all the hoses attached to the filter for splits or leaks. The injector could be the source of the problem, but I would check all those other things first.

Wise move, I'd put it on the throttle side so you don't need to release the clutch to pull the rip cord.

Have you ever adjusted the valve clearances?

Do you have a tether kill switch?

Lets just say, I hope nobody ever experiences a stuck throttle on an EM and if they do I hope they maintain control over the clutch, the computer doesn't have control over the motor speed and ideal would be you have a tether kill switch to shut it down before take off. Unlike an ICE motorcycle where if your throttle sticks there will be 4 guys trying to help you kill it because they all know what a stuck throttle sounds like.

Have you tried the tick-over setting on the EM? It intentionally makes the throttle hang after you shut the throttle down. If the throttle grip hangs then you have a whole bunch of silent engine revs happening and the only thing stopping it from hooking up is the clutch. If it were not for the clutch I would have been launched into a rock outcrop. I only needed to experience that once to know I would never be using that setting ever again.

Now you went and made me think it's due time to change all my fluids, I've been riding her hard lately. ... flush the hydraulics and sand down the brake pads ... buy a new chain ... service the air cleaner ... service the forks 🙄 awcrap I have a lot of work to do this week.

DOT 4 brake fluid in the brakes available at auto stores Are there any farm tractor or heavy equipment dealers near where you live? For 2-stroke transmissions with wet clutch I use all season hydraulic excavator oil ISO46 and replace it frequently because it only needs about half a litre. Been using it for decades without problem in 2-stroke transmissions and Montesa 4RT transmissions.

Personally I found the EM Race clutch provided little to no feedback through the lever, the bike has a propensity to spin the rear wheel and my first thought after riding one was they are geared too low at the rear sprocket. I think if you made the already powerful motor spin up more rapid you will lose any benefit to additional wheel spin. ... most dangerous feature ever is the tick-over setting, if your throttle sticks (and that can happen) it will launch you.

TRS will have the more rigid frame and handles superlative because of it, the TRS foot peg mounting brackets are bolted to the frame making it more serviceable. On the other models the foot peg brackets are part of the frame. TRS generally command a slightly higher price & TRS has the best dealer support where I live, ymmv.

I think the only reason my home built bushings worked good was because of quality control 😆 by turning your own bushes you can fit the spindle to the brass with just the right clearance for the grease you pump in there.

I turned brass bushings to replace the OEM plastic ones and that worked really well. The open cup needles you linked to call for a hardened axle and not just the big bolt they put on the stock bike.

That doesn't look like an exacta alloy fuel tank, looks more like a steel Yamaha TY tank. Problem with the rear end is, the countershaft sprocket is a long way ahead of the swing arm pivot point and the original swing arm is very short. If you alter the rear suspension and sprocket size significantly the rear end starts doing the pogo-stick motion. Angle at the steering head is definitely the source of the slow steering and the leading axle doesn't help that situation. I agree on not wanting to chop the frame and it's a shame you can't adjust rake at the triple trees like they did with choppers in the olden days. Stock forks are spindly and the stanchion tubes are very close together which also limits the lock to lock. The biggest improvements you can do to the bike over stock OEM is to run modern radial gummy tires 👍 and improve the bash plate coverage.

Might want to mention what part of the world you reside in. If you are not set on the Scorpa brand you might want to look at Montesa as an alternative. Used 4T Montesa' will outnumber used 4T Scorpa' by about 7 to 1. Montesa fuel injection and the single cam with screw adjusters engine is far superior to the Yamaha carb and twin cam with shims engine. The really early Scorpa Easy with a Rotax engine suffered from a poorly designed air box that filled with water off the rear wheel during deep water crossings. Same problem Xispa experienced, they drown easy 😉 I called it my Scorpa Drown-Easy.

He needs to follow me for a while 😀 today would have been good

Re: "Suzuki models share the same rear sprocket bolt pattern, as well as alternatives for the front sprocket? I'm going to suggest yes to that 👍 Suzuki used a Lot of parts in common with other models on the Exacta. Great motor! but omg they turn slow at the forks and the Beamish I rode felt like a pogo stick in the rear. What's your plan, gear it slower or faster? A really large rear sprocket will exasperate the pogo stick action and I remember the internal gear ratios are not ideal.

👍 Make some noise is what we usually say, third gear really rocks. If it was a Montesa you'd want to twist it even harder. ...? do you brake and clutch with only the index finger and do you have your levers fairly level of tilted way down. Keeping the levers closer to level helps.

Sad thing is every Montesa comes with a nice big service manual, so the previous owner didn't give you everything for your bike. Like jonny says the parts and manuals are for the most part interchangeable, I had 3 different model year 4RT' at the same time and swapped parts between them to trouble-shoot with no issues. Throttle body, fuel tank, ignition components all interchange with no issues. 2012 model, the first problem you encounter will be valve clearance adjustments when it becomes hard or impossible to start. Everything else on the 4RT is near indestructible and trouble free.

I bet you're riding down a gear, with a 300cc engine 👍 cog it up one notch, they love 3rd. gear and you won't need to grab near as much throttle.

This home built tool will work great for removing and reinstalling wheel bearings, unless somebody failed to install the middle spindle as suggested above. 1/2" Threaded rod, any large 3/4" drive socket that is larger than the bearing outside diameter, 2 nuts & the sleeve part is cut out of a spent CO2 canister like they use in paint ball or pellet guns. Use the same tool to insert the new bearings without the sleeve and replacing it with an old bearing or large flat washer in place of the steel sleeve, no hammer and no heat is required for insert or removal because you can pull the bearing straight in or out. If the middle spindle was left out that is going to make disassembly difficult and if it was torqued down, you may have already damaged your new bearings.

Try Jitsie - they are great when it comes to common needed trials bike parts.

AJP brakes are common and used on lots of models, they don't need to be copied from Sherco because AJP makes them. The gas cap on the other hand might be very unique, that's not the kind of part Xispa would copy. Photos and dimensions of what you have might help somebody to recognize it.

Event was a great success 👍 heavy rain just hours before the start turned topsoil into a slippery slimy mess which roughly doubled the scores, but results were well balanced across all rider classes and near predictable which means I must have done a good job setting up the sections 😎 thank-you to all riders and support workers that made it a great trial. results can be found here: https://www.ataont.ca/ata-arden-trial-provisional-results-july-16th-2023/