konrad

You have my sympathies! That has got to rank as one of the worst ignition systems ever designed! The "pickup" is actually a pair of Hall-effect sensors. You really need specialize knowledge and equipment to diagnose these ignitions, otherwise you just have to throw parts at it. I made some breakout cables to probe the signals and spun the system with my vertical mill.

trialshop.it to the rescue! I'm going to have to learn some Italian. https://trialshop.it/ossa-ricambi-originali/25217-biella-completa-tr280i/ I see it comes with the small-end bearing, just like the GasGas kit. This is unusual, so seems likely it is the GG part. 118mm for conrod center-to-center is probably a good number. I was guessing 120. Thank you. 5 micron (0.0002 inch) runout is perfectly reasonable. I have a dial indicator that has graduations every 0.0001 inch.

The short answer is: I would continued to use that crankshaft. The long answer is: I have not seen crankshaft wear limits for any trials bike. So we are forced to infer service limits from similar 2T engines. A trials crankshaft has an easier life than one in an MX bike or roadracer. The average piston speed is fairly low, but the piston is also relatively heavy. If you feel compelled to rebuild the crank, I probably would not replace just the big end bearing. Typically the rod, big end bearing and pin are all replaced at the same time. Like their gearbox, OSSA did not sell any crankshaft parts separately. As a point of reference, the complete OSSA crankshaft (P/N 3000020211) had an MSRP of $725 USD back in 2013. My best guess for something that would fit is GasGas TXT 250/280/300. They sell a connecting rod set (rod, pin, big end and small end bearings) as part number MT280212100. It has an MSRP of $266 USD today. GasGas also offers the big end bearing alone as MT32050GG-AIZ-1. MSRP of $35 USD. I have been very curious about the OSSA's connecting rod center-to-center length. Could you make that measurement for me?

Your rod side clearance is good. How much runout is 0.5 cents? Is that 0.05mm or 0.005mm? How much small end free play? Rock the rod side to side and measure movement at small end.

I've been working under the assumption that if the clutch slave cylinder is located inside the engine, the system will use mineral oil to mitigate cross-contamination of the seals. If the clutch slave cylinder is located outside the engine, DOT4 will be used to minimize the number of different fluids required for maintenance. Is this a bike that goes counter to my assumption?

trialshop.it is an excellent resource! Their website is the first time I have seen an exploded view of the OSSA gearbox. I must retract that statement. Upon closer inspection, it is for a TRS.

Interesting! You are absolutely right. I see that locker shaft is captive, with a through-hole, and a 14mm bearing ID. I'm getting the feeling that no two EFI OSSAs are identical!

Although I have not needed to replace a crank bearing, I believe so. This will probably be your best option: https://www.splatshop.co.uk/gasgas-main-bearing-with-seal.html Excellence work and many thanks for the write-up! That bike looks clean, I am surprised the motor is in such bad condition. 300 hours is getting up there. I have one bike with 500+.

Just so we are on the same page, I grabbed some images from the 2018 4RT manual. Here is what I think is going on: 1. Oil comes from the pressure pump and surrounds the outside of the oil filter. 2. Oil travels through the filter media and exits via the center of the filter. 3. Oil exits the filter cover and enters the generator cover. 4. Adjacent to the oil entrance in the generator cover is the PRV (excess oil pressure is vented to inside of the generator cover, eventually finding its way back to the sump.) 5. Oil travels through a passage cast/drilled into the generator cover towards the crankshaft big end. 6. Now I'm guessing... Some of the oil passes through the crankshaft and continues on to lube the piston and top end. (Or there's a different passage in the generator cover that directs oil on to those other locations.)

In all engines, oil flows towards the big-end bearing. When it escapes the big-end bearing, it returns to the sump. P.S. From my research, oil filters almost always flow from the outside to the inside. P.P.S. It seems that canister-type filters are the ones that have an internal bypass valve. So I'm guessing you won't find a bypass valve inside the 4RT's paper cartridge.

I assume you meant to write "...not swimming in it."

I am fascinated by these sorts of problems. But I'll start by saying the only motorcycle oiling system I've studied in any detail was for a dry-sump Aprilia vee-twin which was more complicated. So the following is conjecture. The block flow diagram below is for a 1977 Kawasaki KZ650. It represents my understating of the pressure relieve valve's place in the system. Its purpose is to prevent oil pressure from exceeding a preset limit. The bypass valve opens when the oil filter is clogged or when the oil is too thick (e.g. cold weather startup). The bypass valve can be external to the oil filter or internal. I would expect the 4RT to get 100% filtered oil under normal operating conditions. I suggest opening an old oil filter to have a look inside. If an internal bypass is present, there should be a spring and some type of valve. But if the bypass valve is external, and stuck open, I could see where your engine could still be running okay yet have no oil in its filter.

Some thoughts: 1. 260 miles before the first oil/filter change is a long time. Reviewing my old 4RT manual says the break-in period is 20 minutes. After which it implies the oil and filter should be changed. (Personally, I'll probably go more like an hour lacking any other guidance.) 2. Seems to me it was possible to install the oil filter backwards in that engine (and thus blocking all flow). 3. What transpired between the time the dealer said there was oil in the filter and you subsequently observing there was none? 4. Small 4T motorcycle engines sometime have no oil filter, so it's not the end of the world, but far from ideal. 5. The engine would have seized long ago with zero oil flowing. 6. I assume the oil looks used and oxidized, rather than like new (which would indicate it had not flowed anywhere). 7. I also assume that if you remove the tappet covers you will see oil. 8. If you are concerned about engine damage, you should submit a sample of the drain oil for analysis. In the US, I've used Blackstone Labs: https://www.blackstone-labs.com/tests/standard-analysis/ They can determine the presence of wear metals in the oil. I'm sure there are similar labs in the UK.

Now I understand my confusion. Apparently, Gael rode both a 2024 Comp and a 2025 FACTOR-E at Montpellier. Trial-club.com posted a video on FB. Here's a screenshot from the video.

What photos are you using for reference? Honda service manual are second to none. I still have a PDF manual for a 2107 260. It shows routing behind the bars. Maybe the 300 is different. It's worth investing in the manual. P.S. It's great to see women involved in this sport. If it weren't for my wife, I probably would not be riding trials.

This is an excellent first post! I sincerely hope you are not ChatGPT!

I reasoned that an EV with a gearbox introduces an extra complication for the electronics. See: https://www.electricmotiontech.com/home/ev-tech-101#h.i4aqgk34vpex (Covered in 3 section headings.)

Although the ePure's motor does make a lot of torque, its driving force at the rear wheel is still lower than ICE bikes in a low gear. This section is far from finished, but it may help: https://www.electricmotiontech.com/home/what-makes-a-good-trials-motor Although all the sub-pages are important to gaining a fuller understanding of the problem, this one may answer your question: https://www.electricmotiontech.com/home/what-makes-a-good-trials-motor/driving-force-comparison#h.qosto0nr8kmc

I've started a page to keep track of information about this exciting new motorcycle: https://www.electricmotiontech.com/home/em-factor-e

More information via ChrisCH's link: Completely new chassis in geometries and reinforcements TECH TJ2 two-way shock absorber S3 Parts Handlebar DID chain step 520 S3 Parts Grips New aesthetics and FACTOR-E bodywork Homologation as a 125cc motorcycle Weight in running order: 73 Kg Completely new engine. More power, more inertia, more revolutions (17,000!) Four speed gearbox New mechanical clutch with Kevlar discs Controller with new settings Completely new 1.8 kWh battery in interior and structure Renewed transmission system 1,400Nm motor torque (in first gear) Range of 59 kilometers Peak power 19kW

Admittedly, it's a bit hard to tell but that looks more like a 2024 production bike to me. Regardless, nice backflip at 0:51!

Prototype electric trials bike with a 4-speed gearbox 59 km range (would seem to be when using the larger battery) 1.8 kWh or 2.5 kWh battery Peak power of 19 kW Provides tuneability via EM Connect app Clutch is accessible like a normal motorcycle. Claimed to have dropped the weight by 4 kg too. Production to commence "next month" so, February 2024. Mr. Google translated for me, "On the occasion of the magnificent evening that was organized for us in the premises of its brand new and immense new factory, the Héraultaise company presented us with its brand new motorcycle, the FACTOR E, which represents an incredible evolution in the field of trial motorcycles, electric. We listened to the words of Gael Chatagno who told us of this bike that it was at the level of the 300 Thermal and it is on its handlebars that he will participate in the entire Trial 2 World Championship and the French Elite Championship. The powertrain is much more powerful and now has a 4-speed gearbox. The weight distribution is different which makes the bike more playful and more stable. The battery (2.5) has 30% more autonomy, which gives it a range of 60 kilometers. The swingarm is new, the shock absorber is what is best at Tech., same for the Fork The FACTOR E goes into production next month, so you think how we can't wait to try it ."

I don't believe 600 Nm at the rear wheel and a top speed of 62 mph with a single-speed gearbox. The EM's motor is rated about 45 Nm. Couple that with a 14.39:1 total gear reduction and you get about 650 Nm at the rear wheel. (The SiliXcon controller may be limiting peak torque to EM's specified 600 Nm.) With a 14.39:1 gear reduction, the EM's motor must spin in excess of 8000 rpm to go 42 mph. The E-AT 600 would need more than a single speed to have both 600 Nm and 62 mph at any sort of reasonable motor rpm. And there was no mention of multiple gears in their specs.

I looked up the claimed specifications for that Arctic Leopard E-AT 600 Weight: 152 pounds Max speed: 62 mph Range: 75 miles @ 15.5 mph Peak power: 16 kW Torque on wheel: 600 Nm Battery: 72V, 40 Ah = 2880 Wh Titanium frame +$1500 TFT display +$200 Light & Horn +$100 Off-Road Kit +$200 TECH Shocks +$1500 (assume they mean front fork) J.Juan Brakes +$300 Michelin Tires +$300 For a sanity check, my EM Race Weight: 170 pounds (measured) Max speed: 42 mph (true) Range: 26 miles (unlikely) Peak power 11 kW (true) Torque on wheel: 600 Nm (maybe?) Battery: 52V, 1875 Wh (true) Riding trials, I get about 12 miles range at an average speed of 6.5 mph down to 20% battery remaining.

Looks like I can post again. My prior post was in limbo awaiting moderation - perhaps because it contained a Facebook link? That link showed a water pump on the old GG design where there now appears to be an encoder. My impression about the original Plettenberg design was that it used an "observer algorithm" in the controller. This is better than Hall sensors, but computationally intensive. An encoder is more expensive, but better for an application like motorsports.