UPDATE: 12 tooth front sprocket, JTF 1906, fits w/modification of the rubber chain guard to allow the sprocket room to spin and add 2 chain links (128 vs 126 stock). This mod transforms this bike for the better. The rear suspension is now alive; springy & lively, the bike "pops" off ledges, drops & other obstacles. The chain no longer tries to wrap around the front sprocket under engine breaking or when bump starting & requires minimal chain tension (pinky finger between the s/arm & tensioner). If this bike is just going to be ridden in small circles in the back yard or a typical small trials area this mod isn't necessary, but if you want to ride the SSDT or any distance ride like I do then this mod is a must as it gives this bike the legs it needs for travelling at speed in 5th & 6th. The only down side is first is now just low enough for me to climb the stupid steep climbs very aggressively. No more stopping to smell the flowers part way up.

Two other small mods also transformed this bike. It came w/a quick turn throttle tube which I replaced w/my slow turn from my 125. Big mistake. I was having a hard time grabbing enough throttle for the long climbs & not getting into the meat of the power band resulting in failure. Since the first 4000 rpms of throttle are unusable the quick turn throttle works a treat, no more failure.

Another mod was to install the S3 curve pegs which I had kept from my 125. I hated them in short order on the 125 but on the 80, which has to be ridden aggressively, they work decent. Large platform for my big feet & set back. However, the sharp set screws caught me out once already. Hopefully they dull w/time & use.

For my next/last major mod I am going to find a mint low hour 2013 - 2017 KTM 85 SX & do an engine swap so I get what should have been in the frame from the start. Hopefully, better shifting & better running for the first 4000 rpms. In for a penny, in for several thousand more!

 

I have had a TRS80 for about a year for my son. Prior to that I had pretty much every juniors bike available, among which 3 beta 80, vertigo 50s, beta 50s, ty80, multiple osets, on top of that I have experience with beta, vertigo, EM, sherco, montesa, so while I’m not a great rider by any stretch, I have dealt with pretty much every brand in trials.

initally we had some problems but were all taken care by trs which acted in conjunction with the importer in an impeccable way.

TRS shipped a crate engine across the globe in 5 days so that my son could compete in the Nationals, and my son did compete and won on it.

speaking from experience, problems happen with all brands but not many send an engine across the world so that a little kid can ride a race, I can name names and do multiple examples of the opposite behaviour but best to stick to TRS merits here.

the new side case took a bit to be available but transformed the bike and the reliability has been excellent since and on par with the bigger bikes.

not only, but we installed a bigger bore cylinder and the engine took it no problems and the reliability hasn’t changed.

we live on an acreage and my son uses his bike every single day, and every single day this bloody thing starts first kick, hot or cold.

compared with those bored out 50cc by beta with no linkage and concrete suspensions, this bike goes like an airplane.

not to mention we installed a gold super fast throttle.

today I took it for a ride and had my 3 year old standing on my feet, so probably close to 100kg weight and this bike was just chugging along in third up and down hill at trials speeds.

the suspensions are perfect, we added a compression adjustor to the forks to make it a bit quicker but to be honest it wasn’t needed, the shock is absolutely standard.

my son (12yo, 35kg weight) hops this thing left and right and rode this bike in T3 in local club trials.

I don’t know what else to ask to this bike, it’s been a rocky start yes but turned out absolutely great.

While I respect the experience of others, I feel that TRS with us worked in a professional manner and this bike satisfies all our needs.

is it perfectible? Of course! A proper ktm engine or a small expansion chamber would be killer. Some components should drop the chinesium but it does what it promised.

and I repeat, a beta 80 is not even close, from a geometry point of view, and from a engine power delivery point of view. 

UPDATE #2 Gearing & Mods:
While the 12 tooth front sprocket has a lot of benefits it is too tall for some extreme climbs. Turns out the CS splines on this bike & the Beta 80 are identical. I fitted a 10 tooth front & 59 tooth rear in 428 from the Beta along w/126 links of 428 chain. That puts me right in the middle between 9/60, too low & 12/60 too high. Now, first allows me to climb anything slowly, or nearly anything in second very aggressively. Down side is some loss of top speed in high gear & the suspension is back to feeling nearly as harsh & dead as w/the stock 9 tooth. The Betas stock 11 tooth would be an option for a smaller rider & will just fit w/out modifying the rubber guide as necessary to fit the 12.

A second small mod was switching from the quick turn throttle tube (white) to the ultra quick throttle assembly (part # 70129) from the Gold. I ordered the throttle assembly only & not the fancy bearing end cap ($) that supports the end of the tube. Instead I used the S3 End-5 bar end set. Since the first 4000 rpms are unusable, making whiskey throttle & herky jerk moves near impossible, this is a further improvement in responsiveness & rideability.

Update # 3: Cracked clutch case between the kick starter & fill plug @ 155 hours. Gear box oil everywhere, cutting the ride & the season, short. I am amazed it lasted that long based on others experiences & the # of times I have to kick to light the fire (3-7, cold or warm, in neutral). TRS has "updated " the part for 2026, same part # 03031MT100. KTM part # 47030001100 is interchangeable.

Edited September 15Sep 15 by anachronism

7 hours ago, anachronism said:

Update # 3: Cracked clutch case between the kick starter & fill plug @ 155 hours. Gear box oil everywhere, cutting the ride & the season, short. I am amazed it lasted that long based on others experiences & the # of times I have to kick to light the fire (3-7, cold or warm, in neutral). TRS has "updated " the part for 2026, same part # 03031MT100. KTM part # 47030001100 is interchangeable.

Had this problem in the first month 3 times... Got rid of the 80cc and bought a 125. Never had a problem with 125cc...

8 hours ago, AndréNL said:

Had this problem in the first month 3 times... Got rid of the 80cc and bought a 125. Never had a problem with 125cc...

I miss my '18 125, never should have traded down for this perpetual problem. Not liking any of my options from this point, fix it, flog it, replace it.

32 minutes ago, anachronism said:

I miss my '18 125, never should have traded down for this perpetual problem. Not liking any of my options from this point, fix it, flog it, replace it.

I had the same problem. After 3 cracked clutch cases, failed waterpump seal, and a very unstable idling engine all within 10 hours of driving I had enough of it. Although everything was very well taken care of by the dealer i wanted a bike without problems. It was my daughters bike and she couldn't drive for several months or we had to share my trs one 250. So i traded it in for 2024 125 one rr.

Flawless, no issues, just driving and cleaning....

Update # 4: I decided to fix it. Purchased what appeared to be near mint KTM clutch housing (EBAY) located a couple days in the mail from me plus gaskets/seals from my friendly local KTM dealer. NOTE: There is a tiny over priced seal in the power valve assembly. Luckily I was able to reuse mine. Total damage $300 + my free labour & endless elevated blood pressure. This is NOT what I would call an easy job. I rate changing chain +sprockets at the limit of easy. I had to rebuild the water pump in my TRS 125 & that was aggravating enough, the 80s' power valve adds a whole other level of needless complexity.

Pro tip: Remove the power valve drive assembly cap & loosen the locknut while everything is together. This was a bear to do once the clutch housing was oozing gear oil all over my bench.

I wasted the best part of my Sunday to disassemble/reassemble.

Pro tip: while reassembling the clutch casing to the gear box, watch the alignment of the gasket. Mine kept trying to wiggle out behind/below the kick start, even w/all the bolts in their holes.

I thought I had been careful & foreseen all possibilities but no, not quite. While filling the gear box w/oil I spy, from the corner of my eye, oil, fresh & clean & expensive oozing from the box onto my work surface. Turns out there must be an internal hairline crack in the lowest bolt hole for the clutch cover as oil appears to be magically pouring out the bolt head. Drain oil, clean up the mess, install a copper crush washer, refill & voila, no more mess.

Pro tip: If you buy used like I did, Just Expect Every Problem while hoping for the best. Or buy the updated piece from TRS & wait however long it takes. If you buy new from KTM make sure it is a genuine part w/the KTM part # molded into the inside by the drain plug. There are a ton of "new" ones on EBAY that are direct from the far east, AVOID.

Now the clock starts running on how long this casing will last. Judging by how many new/used sell on EBAY, the prognosis does not look good. To be continued.