konrad

Don't fret, in less than 10,000 hours you too can be an expert. 🙂 From my own experience, trials helps other forms of motorcycling more than other forms of motorcycling help trials.

This is yet another example of the kinds of problems I see with all trials bikes. Even if the design is okay, the end result can easily be compromised by poor manufacturing and assembly. The soft alloy spacer was crushed when the wheel bearings were installed at the factory. The condition may have been helped along by a gorilla tightening the front axle. Even Honda/Montesa is not immune to this. While changing handlebars on my 4RT, I inadvertently swapped clamps for the master cylinders. Those parts should have identical dimensions, but they would not interchange.

Tr1Al, I'll take your remarks as an undeserved compliment. Thank you. I've always been much more interested in the "why" than the "what", so I've spent a lot of time trying to figure things out. I do appreciate a challenge, and the OSSA certainly is that. But honesty, I feel the engineering of all trials bikes could be improved. Unfortunately, the market is so small, there's never enough time or resources to do the job justice. I view all motorcycles as just a starting point that I must bend to my will.

I don't think oil is going to fix this. Assuming you are 100% certain there is no air in the hydraulic system (which presents as a spongy clutch lever) I would look at the step in the OE CLUTCH SPRING SUPPORT PLATE. There can be considerable variation in the step dimension, as one of my photos shows. All three of my bikes were different. It's possible Xiu's clutch control ring on setting 1 could fix this problem (or, at least, improve it). Can the previous owner give any guidance if the bike's clutch EVER worked properly? It's also possible there's too much play in the clutch inner hub, and this is wasting valuable pressure plate movement. See: https://www.ossa-efi.com/home/engine/gearbox/locker-shaft#h.ewk76gf4gqtf

Notes I have on my old GG TXT321 say the minimum squish clearance is 1.25 mm. Different thickness base gaskets are available partly to accommodate manufacturing tolerances, and partly for rider preference in power delivery (more squish clearance = softer). When you measure the squish clearance, make sure the head and piston are free of carbon.

I assume you've read my website regarding the OSSA clutch. Did you use Xiu's clutch pack preparation procedure? https://www.ossa-efi.com/home/my-upgrades/clutch-control-ring#h.twzu1hiimf5e Although it's counterintuitive, revving the motor with the clutch disengaged seems to "break the plates free" and reduces drag. You may need to mix old and new plates to find the optimal pack thickness. I read a surprising thing recently in the 2018 GasGas Pro service manual. It said to check the clutch pack height dimension under a load of 1600 N +/- 100 N (that's 150 to 170 kg of force). But it does not explain how to go about doing that.

The basket used to be available separately, but it's unlikely you'll find stock anymore. This aftermarket basket fits 2001 to 2013: https://www.splatshop.co.uk/csp-billet-clutch-basket-sherco.html

Ultimately, you want to use the base gasket (or gaskets) that gives a squish clearance compatible with your riding preferences, altitude, and local fuel. This is done via experimentation. As faussy mentioned, you should get a baseline by measuring your squish clearance. This link illustrates the procedure: https://www.vhm.nl/en/page/technical-support/squish-measurement The "tin wire" is typically solder.

You are a very skilled restorer! I would be interested in reading about some of your tools and techniques. I notice an oven for curing paint; an ultrasonic cleaner; a homemade crankshaft truing stand; the results of polishing aluminum.

Have you seen this video on setting the gear gap? https://youtu.be/z8p1JbhZaMw I imagine that could make noise. No real specification, just not too loose and not too tight. Since you have two bikes, you can make some comparisons. Also, by removing the flywheel/primary gear assembly, you can run the motor by itself to verify that is the source of the noise. Some additional information here: https://www.electricmotiontech.com/home/em-epure-race/mechanicals/clutch

Nice find! So maybe "a" just refers to the airbox side of the butterfly and "b" the engine side? The automatic idle air control is a nice feature. But I guess Honda figures competition riders have their own preferences.

The ECU is integrated into the throttle body. The wiring diagram shows three blocks inside the ECU marked TPS, PB, and TA. I assume these stand for Throttle Position Sensor, Pressure Barometric, and Temperature Ambient. Elsewhere in the service manual, however, reference is made to a MAP (Manifold Absolute Pressure) sensor. So if it's a MAP sensor, I can see looking for intake vacuum. If it's a barometric pressure sensor, that would be on the other side of the butterfly. The intake vacuum theory would also explain why they say not to touch the throttle while kicking-starting. I'm sure the answer is well known since Honda started using this integrated throttle body on the first FI 450 MX bikes circa 2009.

Instantaneous crankshaft speed. The crank slows on compression and speeds up on expansion. Almost certain it must fire every crank revolution until it's actually "running", though. Nice to see another curious person on this forum!

I agree with faussy. It's been done the other way around, fitting a trials rear to an enduro bike for hard surfaces.

What year did that occur?

Trail Tech makes great products, but the problem is that it would measure battery on-time -- not actual motor running time. That's the easy solution. https://www.trailtech.net/en-us/shop/accessories/digital-gauges/tto-mini-gauge/tto-hour-meter/surface-tto-electric-motor-hour-meter/ If you don't mind getting more technical, I can wholeheartedly recommend a product made by your countrymen. I describe it in detail here: https://www.electricmotiontech.com/home/cycle-analyst

I just added some content on the Domino throttle here: https://www.electricmotiontech.com/home/em-epure-race/wiring-diagram#h.art3jj7bkav4 It appears the Domino throttle EM is sells as a spare part will just plug into the early wiring harness. It has two JST connectors, one of which is for the unimplemented switch.

https://www.cpd-usa.com/shop/tc01q-60401-00-00-asm-em-assembly-throttle-domino-epure-escape-mid-22-up-tc01q-60401-00-00-asm-17940#attr=17910 If he does not want to pay the OE price and does not mind doing some wiring, this look similar: https://www.electricmotorsport.com/domino-twist-grip-throttle-with-microswitch.html I think this was the original thread.

It's just a tube. Knock something out on your lathe. I like to start with PVC plumbing pipe if the dimensions work out. Note this only changes the preload / front ride height. It's no cure for the wrong spring rate.

Thanks for reporting that, I was unaware. I will ask a friend if it was implemented in 2022 as well. EDIT: Friend reported his 2022 Race has no additional throttle connector in the loom.

Does your bike even have the low fuel light? Most did not. Just plug the hole by threading in a bolt. One of my early mods was to make a fuel level sight tube, but I ended up not liking it: Photos here: https://www.ossa-efi.com/home/my-upgrades/minor-modifications

Yes, in theory. But, so far, EM Connect's programmability is only relative to the maximum permitted settings. The is no reference to any absolute power or torque numbers. (I suspect the Dragonfly's U-Mapp will be similar.) Edit: just saw that Dragonfly shows power in watts. And even if there were, the meaning would be open to debate. Is it the peak power or the continuous rating? And what happens when the controller decides to limit output based on its internal temperature? There's also the whole question of how having a single gear affects the situation. I've tried to address some of that starting here: https://www.electricmotiontech.com/home/what-makes-a-good-trials-motor But it's far from complete. The bottom line is that driving force at the rear wheel is what really matters.

The 2021 EM Race has a "schoolboy" mode. The Map switch then gives three very low-power settings. But in 2022 onward, this feature was eliminated so EM could use that input to activate TKO.

10mm thread with an O-ring. https://www.ossa-efi.com/home/electrics/sensors#h.pc3f12lv2znb

For US dirt riders of a certain age, Malcolm truly was a legend. A friend had the good fortune to encounter Malcolm in the Mexican Baja, and they rode together for a while. The AMA magazine published excepts from his autobiography. Malcolm's early life was fascinating too. Malcolm's father lived to be 99, and conceived Malcolm when he was 80! https://www.malcolmsmith.com/malcolmstory