Cynic

Stop looking the wrong way. The engine runs fine on the kicker so the engine is fine. Coils etc too. The problem is in the starter circuit. Or the motor. The battery was easy to check. If that's good now you need to check the inhibitor switches.

The point being, aside from a sprocket change there isnt any more. 4strokes are not restricted. The engine is designed to do what it does. Even the latter 2 stroke 125's are weak pretenders to the monsters around in the 90s.

4stroke hp comes from the cylinder head. Cam, airflow, valve sizes, squish. But and its a biggy. All your power will just come from somewhere else. More top end will destroy the bikes torque. A 125 hasnt got much spare to begin with. Esp as a single. The twins were much better but were sidelined by the newer restrictions. People are not giving you grief when they suggest a bigger bike. Its a genuine sentiment. That little 125 is great for learning and shoestring budget transport. If you work within its limits it can ride with the bigger stuff to. If you mates are genuine. Ask andrewelvisfan. He rode with a 250 and a 650 to Squires from Cambridge on L plates.

Like i said your going to generate swarf. This will be ally too which gets everywhere. When you do the punching get the ally hot. Remember your not heating steel. You only need 7 or 800 degrees to melt the case. Pop the top seal out and use a nice narrow flame to heat the bit you want to ease. Good luck.

It starts on the kicker so can only be something in the starting circuit. As that works (as far as the engine turns over and you get a spark) we need to look for the common part. The battery. Airhead takes the gold star. Until the battery is proved ok (12.8v). That's where my money is.

Mine is copper. Just re-aneal it. 2mins with a blowtorch. That just looks like bolt on trouble.

Honestly.. You could maybe cut the worst off. You could try and punch the damage, swarf being the enemy there. Persevere with modifying the shaft to fit. Bearing in mind its cheap and if you knacker it. Replacements are readily available for another go. Replace the crankcase. Up to you but i know what i would be trying. Biggest lesson. For all those reading too. Don't neglect your chain.

Anything wrong with the sidestand. If not use that when your out and use some wood under the stand at home.

Cor wish id read this first. Auto electrician with electric issues asking US for help.....

+1 on the battery. What is your definition of fully charged. Because the charger says so or showing around 12.7v no load.

Don't get too hung up on the drawings. Back then they were drawn by people. You end up with the written equivalent of Chinese whispers. Mind those threaded holes are doing nothing on mine. That seat strap fits to the seat, not the frame. The square section arm does get verbal mentions but as it is pretty much the same as the round arm its nothing to get excited over. Except the fact that the pins thicker. So when swapping round for square you need to change the shock too.

Nah only 1 think kills dt175's no way round it and kills them as sure as giving one to grouch. Revs. They dont like it over 8k cos the piston overheats and either nips the rings or holes.

Lol. Your supposed to use your knees to grip the tank. All your arms should be doing is steering. If you are holding the bike with your arms gues what happens when you get moved by a bump or windblast. Ya wiggle.

Hope it doesn't disappoint. But that boost bottle stuff was to improve bottom end torque. If you want power from a 175 you need the later airbox and a good pipe. Still be flat out at 55.

You will most likely split the ally. Also you will get swarf down there you cannot remove. I would work on the shaft till it opperates nicely in its hole. That will be the safest bet i think.

Thats why i edited the title to tell the difference.

If you want to change the basket you will need the primary gear too. Possibly the other gears as well for the oil pump and taco. Whats up with the old one.

What do you mean? The full clutch. If so most likely yes with the appropriate primary gear,oil pump/taco drive. If you mean the clutch pack. Depends on number of plates, thickness etc.

I had a 600 that was a sleeved down 750. Put 750 barrels on and it becomes a 900, not to mention dif cams, chain, ig, top crankcase and the clutch and gearbox mainshaft were different. On a 100% sound bike low miles that had its oil changed every 3000mls running like a swiss watch, yeah maybe bore it. On a 125 for maybe 5hp.

Problem being, the insurance being the first. Generally to prevent general buggering about the 250 top will not bolt straight on these days. Generally cranckcase oppenings and such need changing. Secondly, Yamaha wont have wasted x pounds on a 250 crank in a 125, it will be a 125 crank. Thinner webs maybe. Def smaller bearings. Weaker clutch too and wheel bearings/brakes. Not enough exhaust flow. Bikes with big bore kits die as a rule. Your asking 30% more than it was ever capable of, as a repair? Don't forget its not first class before you fit the kit. Sensible option is fix the damage and see what else is/may/could be broke when you start her up.

Your engine will be ok as you didnt run it when it was dry (did you?). Bbk will be a waste of cash. Loads of negatives for little real performance. One bolt to sort and a new neutral sw. Then sort the fueling. Bikes tell you their troubles. You should listen.

Just alterd the title slightly to save confusion.

Hey not so sloppy. Its only the bolt you have issue with. The bolt pulls the 2 halves together. With it broken you should be able to remove it at least. If its a dud you lose nothing getting aggressive with it using the serious tools. I see no reason your old pv wont fit. 2strokes can be really cruel to own. They give big but you have to pay the piper.

The bolt or the clevis pins that locate the halves.

The power valve shaft has SNAPPED! How? More importantly its 2 halves held together by a bolt, least the ones I remember are. They may have changed. Pictures would be good. Have you tried the valve from the other barrel. You might be surprised.