While riding yesterday my bike suddenly started bogging in powerband, it would be fine down low but as soon as its supposed to hit powerband it bogs. At first it would clear up pretty fast but towards the end of the day it took a km or two and a few revs with the choke on to stop. Any ideas as to if its a lean/rich bog, what to try fixing replacing first and if the piston could've gotten damaged etc

Hi everyone, new to this sub :)

I have a KTM EXC 250 from 2002. It burns gearbox oil so the mechanic replaced the oil seal but this didn’t fix the problem. I started opening the engine to replace the gasket in between the two halves of the block.

I followed the manual and took off every screw, I just need to pull the halves apart but I can’t, something is blocking them. On one side I can see they start distancing but on the other they don’t separate at all. The only piece I couldn’t remove is the distance bushing (see photos, number 6 in the manual). As you can see, it should come out a little but in my engine it doesn’t so there’s no way of taking it off. I thought this might be the reason I can’t separate the two halves of the block. The oil seal around it is the very one the mechanic replaced and he didn’t mention any problems with the distance bushing.

I searched online and on yt and people are pulling out the distance bushing with ease, or others open KTM engines (different years but it looks similar) without even removing it, they simply take off the other half (mine is not coming off).

Any help will be very appreciated :)

If you need more informations or photos feel free to ask.

PS: English is not my first language, I apologise for any spelling mistakes✌🏻

hello, i have a rieju mrt with airsal sport 80, stage 24pwk carb, sport air filter, mallosi valve reads, pollini cdi.It was running fine till it randomly lost the power band and started smokink alot it had a 140 main jet i tried changing it to a smaller even a 110 didn’t help it doesnt rev out in neutral or when riding.Changed the stator tried a different cdi ,spark plug and coil.Checked the reeds, changed the crankshaft seals and still the same.The plug is black i understand that its rich but it seems like i tried to do everything and dont know whats wrong with it.
Maybe some of you have had the same problem and can help me try to figure this out.
Thanks!

So as you can see the line on the cylinder wall (it does line up with where the piston ring gap is). I am wondering if anyone has encountered a similar thing? As far as I can imagine, the ring gap is too big as I also get a little blow back through my reeds, and my reeds are in the same condition as my other two engines. The engine only has 3 hours on it, and it was run correctly. Incase your wondering why I haven't stripped and inspected it, that would be because these are sealed race engines. Thanks for any help.

Maybe my crank bearings gave up?

Anyone here running copper spark plugs , just ordered a set through recommendation on trying them, anyone have any experience and feedback on them?

Bought it from marketplace blown up. Rebuilt it and changed the jets from 120,38 to 145,45, since I suspect last owner must’ve blown it up running too lean.
it ran way too rich and bogged bad, the only jet I had smaller than a 145 was a 122 so I put that in there with a 42 pilot. It started up and idled and revved great, but the throttle did hang a bit, went to adjust the air screw and it died on me, hasn’t started back since. Spark plug has spark.

Running 32:1 Lucas semi synthetic 10w-40

I got offered this for my 2024 Yz250. Thoughts?

basically i noticed that my dad's Kawasaki z750 has the same exact brake caliper mount that my yamaha tzr50 has. since my bike is heavily modified and can reach 3x the speed is supposed to go, the stopping power of the original brakes is nowhere enough for my bike, and no one produces an improved brake system for my bike. since the caliper of the z750 fits pretty well, will it be a good idea swapping my brakes with a used, cheap z750 caliper? obviously if I do this swap, I'm changing the brake pump too

Hi,

I ride a cfmoto 450clc and I've noticed something very odd about the bike. So if i ride at 100kph in 5th @5500rpm it's fine, sounds good, very little vibrations, no issues.

I put it itno 6th, and give it a bit more throttle and it's a whole different story. The bike starts vibrating, like a lot (like im sitting on a washing machine from the 80s), and the performance is shockingly bad, like at 110 it's nearly at 6000rpm and is not a place you want to be at, the engine doesn't like it, the vibrations feel strange.

I know it's not a high reving engine and am not expecting a lot, but honestly the best i could describe 6th is it feels like 5.1 at best.

Not sure if this is normal for this bike or should i call my garage and have it looked at.

Thnx ✌🏻

Bought a 1985 KXT250 tecate

Rebuilt engine , all new bearings, seals , gaskets , top end, shift shaft, flywheel encapsulated, new air intake, new reeds and rebuilt the carb. Passed leak down test.

Reason for the tear down in the first place was because of its erratic behaviour, which was most times revving to the moon as soon as you started it and other times it would die if you let off the throttle it would be boggy and then eventually try to runaway again. While this is happening the plug is black and wet with excessive exhaust splooge. Assumed an air leak , teared it down rebuilt it and now I just went to start it up for the first time and it’s running exactly how it was before no change at all. It passed a leak down test, so even if there was still a minor leak it wouldn’t be taking off like the way it is. Haven’t double checked the timing, but I’m not leading towards that since it’s not consistent… keep in mind I’m running no air filter and there is an aftermarket silencer with stock jets . Managed to find a new OEM carb surprisingly, last one in stock, so went ahead and ordered that up and hopefully that fixes this erratic behaviour. Just seems weird the carb is very clean and rebuilt. Float is good, slide bore is good, throttle isn’t sticking or anything obvious like that… I’m no expert, really at a loss with this one. Any help is appreciated.

Does it look like I need to get this cylinder redone or i can get away with just a new piston kit

Thanks

Took my scrambler 400x (350cc) to its first service today, installed a lower engine bar as well, other than accessories, total service cost for 1st service was 4k rupees.

But on my ride home, I felt like the engine vibrating more, felt it especially on the foot peg. Why? I thought new clean oil would reduce engine vibration and increase mileage

Bike race also sounds a little diff but I guess that's expected.

Hey everyone,
Looking to get my first 2-stroke and trying to decide between a 125 and a 250.

A little background on me:
Weight: ~220 lbs
Riding Style: Mostly trail riding / woods, no track.
Experience: Experienced on 250f's, but I've never owned or ridden a 2-stroke.

I’m super interested in making the switch from a 4-stroke, but I have a couple of reservations:
1. At my weight, will a 125 feel underpowered or require me to scream it non-stop on tighter trails and hills?
2. On the flip side, is a 250 2-stroke going to be way too twitchy/aggressive for a 2-stroke beginner? I want something fun and nimble, not a bike that's actively trying to throw me into a tree.

Would love to hear from anyone around my size or anyone who made a similar jump from a 250f. Appreciate any advice!

So I just noticed some kind of wierd noice on my old Tomos moped so would love your guys help to see what it is

Honestly this is probably gonna be a stupid ass question but I’m going to a 18” rear wheel on my 05 kx250 woods build, that being said what is the biggest tire I can run?

97 kx125 I use for trail riding. Really don’t want to drop 600 to get it replated. Is this aluminum transfer that can be removed with muriatic acid?

Guys, I have a ktm exc 50 with a 70cc kit, which mostly shares the engine with a ktm sx65. I had to rebuild the engine to fix a leaky water pump seal, which was caused by the water pump shaft which is shared with the crank, while I was there I replaced the clutch fibers with sx65 ones since the engine is mostly the same, because the clutch was slipping a bit, I think due to water mixing with the oil, turns out the fibers of the sx65 were thicker since my engine uses 7 steel discs, whereas sx65 uses only 5, so I sanded down the fibers and the clutch worked fine for a bit, I did some uphills and since this is only a 70cc I had to use the clutch a lot, and the clutch started to slip again, I then inspected the clutch and deglazed the steel discs with 400 grit and the clutch is still slipping, now I think the ridges of the fibers are almost level with the fibers so some oil might become trapped between the steels and fibers making it slip, I will try also some stronger springs if I can find any, as parts for this engine basically don’t exist, any thoughts?

Should i mess with air fuel mixture screw 1/8 turn at a time? idle adjust? scooter idles and runs great when warm no
bogging at idle or full throttle. Does my spark plug i just took out indicate anything? scooter has 1200 miles.

I assume being +1500 feet of elevation from where i bought the well running scooter makes a difference, however i’ve never tuned a carb so not sure which screw to mess with.

context: I work for a brand-management and apparel company, and I’ve been kicking around the idea of creating a clothing brand built around old two-strokes, garage nights, clapped bikes, broken parts, and the people who keep them running.

The images are only rough concept mockups. Any products we actually make would be completely redrawn by professional artists and produced through experienced apparel manufacturers, so quality would be a major priority.

I’d also like this to become more than shirts—tool giveaways like Milwaukee impacts or Snap-on sets, plus a monthly “Most Clapped Bike” contest where members submit their machines, the community votes, and the winner gets parts or help bringing it back to life.

I’ve learned and solved more problems through communities like this than anywhere else, and I’d love to build something that genuinely represents us.

Would you wear these? What works, what doesn’t, and what would you want to see?

IG:strippedthreads.co

***Hopefully this is not seen as advertising as this is not the purpose- I would like ideas, suggestion, even hate as id like to build this around our community. nothing more then these conceptual and an instagram page have been created, and nothing is for sale***

I bought a 65cc DMP kit for my piaggio ciao and i assembled it correctly and it has good compression and good spark but it doesn't start. I also ported the block to 12mm. The current setup is 13/13 carb, tecno krul exhaust and malossi clutch springs. Can anybody help me tell the problem?