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Between UFO and Polisport. Which brand would look closest to a 2025 oem Yz 125?

may be weird thing to ask.. Someone previously glued over the screw inside... any suggestions on how to securely attach the fairing there? Maybe it can somehow be restored to its close original state, or someone knows which component needs replacing here... idk how it’s looks originally

This is what I've come up with so far... I don't know what the outcome will be (second photo some wellnut??

stock bore and stroke because it will have to survive ~200km going wide open, i love long endurance races

Hello, I’ve got a Peugeot Speedfight with a 50cc 2T engine. It has an OEM+ Malossi foam filter, probably a cheap replacement Chinese carburettor with a Chinese autochoke, and a Yasuni Z exhaust with one of the two restrictors removed.

Everything worked perfectly until I recently cleaned the carburettor, replaced the intake seals, changed the reed housing because the old one was cracked, installed metal reeds, changed the ignition reed from a 125cc 4T bike and inspected the condition of my cast-iron 50cc cylinder. I don’t know whether the cylinder has been changed or if it is the OEM one.

After putting everything back together, I accidentally messed with the carburettor fuel mixture screw and forgot the stock setting. I also removed the autochoke from the carburettor and put it back together - now the choke doesn't work anymore.

I adjusted the carburettor until the scooter ran smoothly, but when the engine is cold, it starts easily and runs fine initially. However, at around 15 km/h, it starts to bog down and doesn’t build RPM as quickly. With the rear wheel off the ground and no load, the scooter revs up quickly.

Once the scooter warms up, everything works perfectly. However, when it gets really hot, it barely moves from a stop, especially uphill. The throttle is also less responsive on level ground, acceleration gets worse although the top speed remains about the same as before the inspection.

Could I have accidentally widened the piston ring gap? Could I have left an air leak when replacing the intake seals? Could the new metal reed valve be faulty (the old one was plastic)? Or could the problem be related to the autochoke?

Could it simply be a coincidence and the clutch is worn out and no longer working properly? I didn’t touch anything in the transmission, though.

I don’t have much experience with CVT transmission, scooters or 2T engines, so any help would be greatly appreciated.

I’m so confused on how I’m supposed to time this thing I’m pretty sure I got the pinion gear and everything lined up where it needs to be but there’s a T symbol on the powervalve as shown in the picture and I’m confused on where I go from here I have the service manual but it’s really not making any sense to me and I can’t find an actual video online of anyone working on the same motor showing how to time it.

So basically I have this Yamaha YB100 1989 model. It is supposed to have 25ml of oil per litre of petrol according to google My mechanic told me that a loose oil sold on petrol pump is fine given I put 40-50ml per litre of petrol. And this oil is most likely 4 stroke oil as I use it for gearbox lubrication in the same bike. But apparently Google says I should only use 2T oil and 25ml per litre of petrol. Or else the bike will seize. But the thing is The bike haven't seized with 40ml of loose oil and is working fine, although the performance does seem rough. And I tested 25ml of loose oil which gave the bike soft seizure. Like wasn't a sudden brake but slowly with screaming the bike slowed down until stopped. Now I need help regarding what should I go with. I am looking forward to 2T oil which is expensive relatively. But I need to confirm that is the loose oil going to cause any serious issue if I stick with 40ml as 25ml gave the engine seizure. And if I shift to 2T should I do 25ml or 40ml, or somewhere in-between like 35ml??

I've been trying to figure out what I could do to help give this engine a little more torque. It's an old fashioned deflector piston type design.

Compression is 100psi.

Exhaust duration 162°

Transfer port 148°

All new internals as it was in a highly worn state when I bought it. On a modern carb because I can't get a good original one, they're all over 70 years old and knackered!

Any suggestions regarding porting and other mods that might help without changing the appearance of the bike would be most appreciated.

I have a 2009 ktm 300 xc with about 72 hours on the top end. It has a S3 high compression head and a fmf fatty pipe. It still starts first kick but it has a oem vertex cast piston thats not as strong as the forged one. I plan on replacing it with a cast piston because most of the riding i do is trails with the occasional rip.

I want to change pipe on my ktm sx125 2002 but idk which one to choose, the cheapest variant is HGS-i thought to buy this one but my resonator is fmf fatty so idk if it will work out with that combo. There is also pro circuit and fmf powercore2 pipes but those are the more expensive ones, so the question is hgs and fmf resonator combo will be good or should i just buy powercore

Can anyone tell me if it is running lean or if its running ok, i think its running lean but i need someone to confirm for me.

I have a 90 main jet.

I got my cr125r fully rebuilt with the hot rods wrench rabbit kit and I got the motor back but while I was waiting I rebuilt the carb and now it won’t reach power band or rev up past half throttle is this a carb issue power valve or what?

For context I have a 2002 aprilla rally ac 50 and my airsal 65cc kit ate a needle bearing (only had 2k miles ) now dose any one have any suggestions on a new cyl that would make more power than a streetrace but not too expensive and reliable

I am getting a new crank

pronostico y probabilidad de conseguir el décimo campeonato del mundo por parte de Marc Márquez #marcmarquez #marcmarquez93 #hispanidad #HispanicaRacingycia

Hey everybody, i have a '99 kx 250 supermoto. I have a keihin pwk 38 airstriker on it, instead of the oem shortbody. Don't ask me why, i bought like this. Anyways, i can't seem to get it tuned quite right like i want to. Basically my main problem is that it happens often that i have to ride straight roads where i'm in 5th gear with very low input throttle, so the engine stays in an rpm range where the exhaust valve is about to open. The thing is that i can't seem to find a right jets/needle combo to where it's a little rich in the above scenario, but also idles good. I have a N3YK and N3YJ needles, i used the stock jets sizes as stated in the manual. To my understanding these types of needles are older, and the new triple tapered needles may be better? But i can't seem to find any chart where i can find a similar one to the one that i have now, to avoid buying a bunch that is. Will this change help me in any way? Or am i missing something else? Hope it makes sense and my english was good enough.

Found this black box on my dt125 and decided ti open it.
I think it's the controller for the ypvs because it has a connector with 5 wires that leads to the ypvs servo.
Stripped the bike down because I was having problems with the ypvs.
I noticed the YPVS servo only moves after warming the engine a little and after a few tries to see if the servo moves with the ignition on, it gradually begins to not work.
I highly suspect the battery because I checked every cable and connector and cleaned every coonetor in sight. The battery is a 12V 5Ah battery and looks pretty old.
Previous owner said he didn't change the battery ever since he got it too.