miner

Imgur working again now… https://imgur.com/gallery/PCrkpHN

Hi - this disintegrated whilst rebuilding the bike… any idea which part / part number it is? I can’t see/find it in the parts book. 🫠 07 TXT Pro 250. Can’t add or link it at the moment… it’s a plastic part that’s right under the headstock and the tabs come round the frame.

The main bearings were ok, just swapped out the gearbox bearings as a couple of them were grumbly.

Cool. Checked the 300 KTM manual for comparison, just says to fully butt it up before putting the other case on.

Is there an end float dimension/spec for the crank when refitted the casings? Doing ok with the exploded parts diagrams and mechanical nous… but want to check this one before I pull the crank and bolt it back up.

Aye. Tribology (mating faces and lubrication) is a science on its own, a deep rabbit hole to go down. 😵🤯🤓

Quick google brought this up… covers it well. Torque values are not compatible but it’s not just about that, it’s also about loading area and retention of lubrication. https://www.gordonrussell.com/articles-3-the-differences-between-planetary-and-spur-gear-motors This one covers gearbox types very well. https://granvilleoil.com/news?artID=9#:~:text=The most obvious answer to,fluid is for automatic transmissions. There’s also the specifics of the oil itself and it’s shear resistance which leads to reduction in viscosity over time under load. https://www.marinelink.com/news/analysis-oils-what353514 For a trials engine’s torque output, its maybe ok depending on the fluid used… but if it was meant to be used with ATF the engineers would’ve specified it instead of 10w-40 (or equivalent). Being an engineer I’m going to side with them. Also got sick of dumping silver oil out my old KTM when running ATF in it. Might be ok but it’s a no from me based on the above. 🤓🍻

Went out yesterday to get two 25x1.5 o-rings, 35x45x12 needle bearing, 12x20x5 oil seal and 10w-40 semi synthetic oil... came back two hours later demented with two o-rings and ordered the rest on desert cart. Ordered two quarts of Lucas 10w-40 semi synthetic. Suitable grade hydraulic oil not a bad shout. I don't like ATF as its not intended for pinion geared boxes... BuT bUsEs uSE ATf AnD tHey'Re MAssIvE!! They sure are AND full of clutches... but people on the internet don't understand anything about the difference between pinion and planetary gear sets loading. 🤓 Might be OK... but its not for me. Would prefer a light hydraulic oil. 😁

As above… cases are split to do the gearbox bearings and replace the o-rings in the gearbox crank seal side (all good, just worn o-rings appear to be the source of burning gear oil). Anything particular to watch out for when reassembling? Never done it but between the KTM manuals and the Jim Snell videos, should be able to figure it out. Any pointers welcome.

Cheers guys… I’m not a big fan of ATF… but I do have a surplus of Mercon V & LV to hand. 😅 Semi-synthetic becoming old hat nowadays, most things are synthetic now. I switched to fully synthetic in my CBR600 and the clutch was toast 1000 miles later… it was ~26k miles old by then, subjected to track days and super sticky track rubber in that 1000 miles though. Clutch springs also 0.3mm off the sacked out limit. I could be being a little paranoid about semi > synthetic. 😅 Not the switch from mineral oil it once was on the motors.

Cheers Zippy, that’s spot on. Might just being paranoid… best to get the tyre off and check. 🤞🤪😅

As above… anything to watch out for? Bike (07 250 TXT Pro) has a rideable slow puncture. Band was replaced a couple of years ago with the tyres and the rear rim. It was leaking after being rebuilt by the shop, they sealed it and also trued the wheel up. Wary of what I’m going to find when I pop the tyre off… maybe it’ll be as simple as swapping the band?🤪

Anyone switched from semi to fully synthetic on the older TXT Pro (07 250)? I was able to get Petronas 10w-40 semi before and maybe able to get again… fully synthetic will be easier to get though. Mindful of the clutch and not sure how it’ll take to fully synthetic? Bike currently in a hundred bits… but finally getting the time to rebuild it. Front and rear wheel bearings changed, carb stripped and floats replaced. Don’t have enough 5w oil as finish the forks today, ordered some from Amazon. The Petronas oil is massively overpriced on Amazon, as are most of the other semi synthetic options.😬 Front and rear brakes to do, going to strip the callipers whilst the bike’s in bits. Also a bearing, oil seal and two o-rings short for doing the motor bottom end. Pick them up midweek. Hopefully have it done over the next weekend.

Yes correct. Found a pair if forgot I’d bought a while back when I realised spares would be a pain to get. Cheers guys. 🍻

Got some play in mine, just spotted it, most parts places closed until into January… anyone know the spec/numbers for the bearings? Lots of places still open over here in Abu Dhabi, should be able to source them. Cheers. 🍻

Good point, his videos are spot on. 🍻

Signed off for a couple of days with sinusitis so more antibiotics and another weekend off riding… so thinking I’ll take this weekend to do the rainy day jobs on the trials bike. Main job is the crank seals plus got a new pair of piston rings to fit plus I’ll repack the silencer, grease everything whilst it’s apart, etc… anything to beware of when splitting the cases on these? Every other part of working on them is quirky so expecting something, don’t think there’s any consumable parts I’ve missed like lock tabs on the clutch basket or anything like that… just steady away and take lots of pics whilst disassembling… feedback welcome. Cheers.

Settled on the 44/10 pair that I bought first 🤪 I found a review of all the boot fits on here and somewhere else that said the Forma boot fit on the heel was looser than others but was also dependant on the middle strap. Adjusted that, feels better. Also wore the 43/9 whilst watching WSBK Race 1, half an hour in them was enough as convince me. Ok length wise, little narrow, like most Italian boots. Sure with heavier socks and trousers on they’ll be ok once bedded in. Happy with the boots, look smart and well made. 👍

Long time no posts… I finally got round to buying a new lid, can’t find the old post I started but just wanted to share that I bought an Airoh TTR-S (convert red, white & blue 🇬🇧) and it is indeed very well vented. My first Airoh, tidy lid. Stacks up ok along side the Arai and 6D lids in the fleet. Cheers for the pointers.

Anyone know what forma boots like at breaking in and stretching? Bought a 43 & 44 in the boulders and don’t know if I need to break one pair or wear thicker socks for the other… one’s a bit big and the other a bit tight round the instep, my feet appear to be half a size in between. 😐

Still using a little gear oil but not smoking yesterday, bike felt good, throttle response was ok, good bark but probably a centre box/silencer full of sludge. Steamed out a couple of times without the fan coming on whilst rock crawling, after that it was fine, assume it was air locked. Mrs is woring tomorrow so will go for a hangover buster in the morning... splash of fuel, oil and coolant and should be good to go. On the plus side... felt much better yesterday, months of layoff coming good with reactivated muscle memory... cant bring myself to strip it yet... want to ride it.

Manual says 50:1 but I just run the same 60:1 I mix up for the 300 EXC.

Silencer re-packed not so long ago.. oil level going down, stinks, smoking heavy, oils coming out when revved hard to check it was revving clean, responded to a little more on the fuel screw, was smoking after it was stopped, deffo oil. When I stripped it there was black gloop in the cylinder head, put it down to re-using the o-rings as it wasn’t right afterwards. New o-rings, base gasket and water pump seal, now smoking... will give it a couple of rides and see how it goes but going to start ordering stuff in parallel.

Forgot I’d started this thread... after a couple of rides the thing is smoking like buggery and getting some oil on the pipe... time to strip it. Asides front thinking like an enduro engine... what would you advise to do/replace whilst the cases were split? Bike is solid but for me if you are going in deep to do the crank seals on a 12yr old bike, its time to replace bearings and do the top end at the same time. Thoughts?

Got round to fixing it eventually, holidays, work, riding the 300, its taken a back seat but my riding buddy broke his arm so back on the GG for a bit... swapped the head o-rings with the new ones once they arrived at same time as rebuilding... had to take the subframe and both sections of the exhaust off, to remove the radiator to do the o-rings again... wasn’t fun. ? Flushed the coolant channels, refilled with redline supercool, cleaned the carb, etc, etc... stuck it all together and took it for a quick test ride. Started second kick with stale fuel, sounded nice and crisp revving it, felt strong on a few laps round the block. Bike looking good, be a shame to get it dirty but cant wait to get out and play. It’s in one piece again.... :) Thanks for your help. ?