tsiklonaut

So I got the Btwice flyweel kit and started to fit it but stumbled on two issues: 1) while nice kit there are no fixing bolts included (kit only comes with the weight and the cranckase extender shim) 2) Original gear shifter doesn't fit with extended crankcase size (it's against the magneto door and you can only shift downwards, upward's it's stuck against the door) How did you overcome those two issues: What bolts did you use to fix the weight on magneto w/o it going out of balance? Did you have to remove the magneto to fix it (manual states some special tool needed for this, can it be done without the special tool?) Got another gear shifting lever? Million thanks in advance! Margus

LOL, a good one. Fixed it to "EFI maps" now or should I spell this out for you too?

You're sure it measures the pressure too? To my knowledge it's just the temperatures (air and engine), but since 2-strokes have no Lambda-sensor feedback from the exhaust for mixture adjustment thus they cannot adjust for the high altitude (this must be done via proper re-mapping?)

Let's stick to trials solutions please, those are more rare on ice (our lakes are so full of those superbikes or enduro/cross bikes with studs so it's getting into old news category already)

Anyone knows if there's a high altitude (2000-2500 meters+) EFI map available for TRi?

Very little info on them, looks extremely rare and it's definitely a special custom made set to fit the individual needs. My bike's seen a lot of crashes and bruising so lots of wear marks, but I completely dismantled those Take-Pajas and observed the design - they are really top notch quality while extremely lightweight, even my BMW levers, which I consider very high quality don't compare to them. Even makes the AJP support look like some really cheap chinese part (as you can maybe see on the pics too) Google to help: Take-Paja factory in Finland does precision machining on wide spectrum, from machinery to weaponry. Not sure how to get hold of them since I know very little Finnish language myself. If there are other guys who're interested, maybe I can dig up the info from the previous owner who specially ordered them from factory, maybe Take-Paja produces them in a small patch if there're some 10+ sets preordered.

Good info and perspective there. Albeit I will NOT get rid of handlebar endplugs since I do not want to perform surgical cut to some bystanding observer or on myself, and please don't ask me how I know!!! (9 stiches under my eye and almost lost my right eye - after that, round handlebar end caps are mandatory! ) How are the OSSA stock levelers, worth it? or should I look some third manufacturer's standard-sized levers? Cheers, Margus

Wowza, found one in local web-shop, costs just 1-2 EUR. That's very good price if it lasts at least couple of dozen starts, my only big question is how long they'll last. Looks like a test might be in order: I'll pop A23 in when I can find a holder for this size.

Never seen those for sale. Seems like some special and rare battery, where you can normally get those? Albeit very small too - I imaging it empties quite fast while very expensive to buy(?)

My TR280i came with those short custom made levers installed by the previous owner: I really like the feel on them and after also doing some research those are very custom made levers made by Finnish premium manufacturer, you can't even buy them anywhere (special order only). Aside from very good feel what I really like about them is they don't pressure all of my fingers like the normal long levers do (and especially annoying and loss of feel when the lever messing with my wedding ring, but with those Take-Pajas are perfectly designed for 1 or 2 finger use without touching the third or forth when pushed down) But makes me as a novice trials rider to wonder what's the concensus among more experienced trials riders, do they tend to "upgrade" to some shorter custom levers or they tend to ride the stock long levers?

It's a much more complicated schematic though. OSSAs battery pack (8 x 1.5 volt AAs) makes 12V then. With 9V there's no fuel-pump noise when you activate it, hence I think 9V just helps to support the circuitry (and capacitor) to have just enough start-voltage to improve the firing up engine. 12V battery pack is proabaly is even better support and hence it even starts up the fuel pump, but this huge battery pack weights a lot too I reckon vs a small lightweight 9V battery.

This seems to be the maintenance kit they offer now indeed. Let's see once it arrives.

Good info there mate, will check them out I reckon

Had a quick dash outside today. Mostly trying out studded tyres grip, doing some power slides 3-4th gear full throttle at higher speeds using all the pop the TR280i could offer, was exhilarating fun doing ice/snow riding first time in my life and finding that balance point on higher-speed slides. But noticed I had less and less grip after some 30 min or so riding - turned out rear studs were almost worn out and corner ones ripped: I mean it was just some half an hour fun. Those supposed to be high quality studs so what the hell causes this, metal too soft or just OSSA having too much power for them full throttle? Front tyre's studs were just extended out: Too soft tyre compound (doesn't hold them) or too much speed (centrifugal force pushing them out)?

I think so, they are all ROM-based, meaning flashable - that's how the dealers write the new map versions. EFI mapping is nothing more than a simple table with parameters written on the ROM chip: throttle-body opening angle according to RPMs, air temperature & engine temperature - from there the ECU will "see" how much fuel to give over the injector for each RPM and condition (a speciefic data "line" in that table). Advanced EFI systems also have the Lambda (O2-) sensor feedback (closed loop mode), this will measure the exhaust gas from the exhaust. Two stroke EFIs don't have this closed-loop mode to my knowledge since they'd "clog" up the Lambda sensor with oil in fuel. So in essence it's a very simple system and considerably more controllable over real-life testing and just remapping according to riding requirements or conditions than any carburator can ever offer with even the most advanced jetting. The OSSA diganostic cable is just a regular USB cable to ECU connector and to pay 200 EURos plus for this seems like a daylight robbery to me. I wonder if we could just solder one ourselves and get the required ECU ROM flashing software?

I counted you need more than just 100-300 pcs that most kits offer, so I went for Pro Gold (1000 pcs) kit in the end that seemed to be very reasonably priced: Works perfect with the standard electric drill socket: Since the studs are very large and agressive in size I made this kind of pattern so it has the required rubber-contact as well in case you hit a hard surface that has no ice, thus providing some rubber grip as well. Rear tyre: Front tyre: The front tyre was a bit of concern in case the 12-13mm long studs go through the carcass and puncture the tube, but it holds allright so far. Hopefully have time test the grip in various conditions in the near days.

Ordered the Marzocchi maintenance kit, in OSSA factory repair manual it states it's a 7-piece kit but the dealer said it's only the two seals. I wonder if Marzocchi figured they've been overdoing the required service parts or just the dealers figured it's an overkill?

Good question! Once started, it feeds 12V onto the battery contacts and after that it's a random guess - 12V isn't too much over the nominal 9V so it depends how good the battery is built, after some time some batteries may smoothly melt-through (push out some little liquid green cr*p and just disconnect themselves from the system), some batterys can expand or even explode and worst case it may even start a fire (I've done this when I was young bastid myself, albeit it needs higher voltage than just 12V ). Hence I highly recommend the kill-switch type to avoid this "I forgot" problem alltogether.

It's for the earlier OSSA fuel-injected models that tend to be hard to start. Since the original thread is 24 pages and very hard to follow and confusing OSSAs own easy-start mod with various DIY mods or tweaks, here I'll put down a simple DIY mod into a single thread: You need: - 9V battery - 9V battery holder or connector - switch (or even better if a Yamaha-type kill-switch) - little bit of light wiring (some 5-10 inches total or a little more if you route to handlebar killswitch) - some longer straps to fix the battery (and for the switch if you don't use kill-switch) And a mandatory very important note to any DIY mod: DO THIS AT YOUR OWN RISK! (and may I point out it's well worth the risk if you're tired of too much kickstarting the bastid!) For those who like to be 100% sure, see the schematic here (courtesy of ric h). I salvaged my 9V battery connector from an old smoke-detector ment for rubbish bin - zero cost. If not, buy a random 9V holder (couple of bucks). 1) Remove the front plastic plate, behind you see the big capacitor with two wires going in. 2) Connect (best if solder all the following connections, this lasts longer and much better contact) the red wire from 9V battery holder to the red wire from the capacitor. 3) Connect the black wire from the 9V battery holder to the random side of the switch 4) Connect a little wire from switch (the other contact of the two on the switch) and leave the other side open 5) Fix everything down with straps and connect the open wire to random place of the bike's frame (I just put it between one of the 3 bolts holding the front plastic plate) Yer done! (->) Activate the switch only when you need to kickstart it, once started switch back (<-) Since I don't have a kill switch available I used the simple switch, but I'd highly recommend using the kill-type of switch. This will make sure you don't forgot to switch back after the bike has started. With kill-type switch you just hold it down while kickstarting and let it go once started. I have 2013 model with the high compression head and it's hard and tiresome to kick it even nominally. Before it was around 10 kicks at least when cold (or even sometimes 20 on a very bad day!), some 3-5 when hot. After this mod: 1-2 kicks cold, 1 kick warm! Starts like a dream now and even doesn't need that exceptionally sharp-kick, just a nice average kick will do the trick! My OSSA TR280i definitely got from being a very good bike to excellent after this mod. This relatively hard-to-start feature was by far the most negative thing about this bike and this mod took it another level literally. This mod should work on all OSSA fuel injected bikes: TR125i, TR250i, TR280i, TR300i & Explorer since they all use the very same EFI system as far as I know. Hope this helps, Margus

Sounds good, sent you a PM!

Sums up pretty good. They're a small player with a hell lot of uncomplished potential had they continued their pursuit refining their ideas and design. I think OSSA naturally gets a lot of hate for it's "out-of-the-box" thinking and engineering (with obvious risks and the need to fine-tune as the experience comes along) while the dominant most other makers follow the classic design (where everything is pretty much settled over the years). It very much makes OSSA a "black sheep" among trials bikes and we all know what happens to black sheep in a heard of whites. I mean just count how many people negatively comment and speculate here without even owing one plus it tends only to happen in OSSA thread in this kind of magnitude - people just check in to let their personal hate go. offtopic: jkmr1, where did you get the wider bash plate, or you just built one yourself?

I've heard the same denialist story for my vintage tape deck that was produced maybe 20-30 units a year in 80s for a couple of years run only and I still run it full time in 2016 with fresh parts coming along nicely. So I guess it's better to stop wondering or speculating if you haven't owned a particular brand and looked for speciefic parts like the real owners do. I just two days ago asked OSSA parts stock reqest from my dealer here in Scandinavia (possibly the FARTHEST place from Spain here in Europe) - all consumables in spades, but he also has stuff like cylinder bores from A to C, pistons from A to C grade, all seals for hydraulics (upper and lower kits) in stock, even stuff like spokes, small plastic bolt kits etc. I imagine it's even better in Southern Europe where there's bigger trials market. Hence I'm confident there will be parts available for newer (I mean post-70s) OSSAs.

I very recently bought mine, also s/h so I'm maybe good one to answer. I was aware of the detoriorating OSSA brand health before buying, but still opted to buy one after doing considerable amount of homework reading many reviews on different trails bikes in 250-300cc class. No bike is perfect and TR280 isn't perfect either, but it was the best to tick most of my boxes. About spares etc: I don't consider this a problem. I own an older BMW that's supposedly hard to find parts since it's out of production for over nearly 2 decades, but never had an issues, also own a vintage and a very rare R2R tape deck and still manage to run and maintain with fresh parts no problem while everybody said it's impossible to run today. Plus I have additional experience of personally knowing people who own bikes from 1920-1930s or just some hyper-rare motorcycle - I've seen first hand how they just make parts themselves (from machinist or CNC workshop), just unbelieavable stuff you though only factory can do, but they proved they can even forge a crancase when you need to and most of all: most of them at SURPRISINGLY reasonable costs that can even rival some redicolous OEM parts prices we pay (no joke)! So I'm not put off even if OSSA dissapears, for some 5-10 years parts will be available from old stocks, after that it's like owning another rarity or a collectible bike - you'll still manage easily. Just me 2c.

With GP bikes it's different story, I.e. Ducati V-Twin engine was speciefically developed for out-of-the corner controllable traction for a human rider to feel out (w/o overdoing and thus highsiding), but this is for tarmac and it's completely different ballgame in terms of traction and grip. Offroad bikes mostly require more "pulse"-like power, especially for better grip over the loose surface. I remember experienced offroad riders said a very lightweight, powerful and capable Aprilia RXV (V-twin) had this too easy to slip issue, because they have denser "pulse" rate over the crank, it's two bangs vs single bang vs single-cyl motor. Single cylinders all have this single-pulse-over crank, but the "smoothness" in actual conditions isn't just about this, I think it's also is how it works and pulls over the entier RPM range over dynamic use of throttle both acceleration and decceleration stages, not just one speciefic RPM range riders keep bragging about. 2-stroke engines are infamously bad for smoothness over the entire RPM range (little power below, but sharp rise on top). OSSA has adressed this issue the best way (a proper precise EFI mapping vs "gut-feeling" with a fiddly carburator) and has done very good.