@calum have you looked at the video i linked above? Do you think it's to loose? Could the bearing be the problem

@calum that’s piston though mine has perfect compression and suprising power

@declan so I’ve adjusted it and to get the right bite point I have to have no slack in the cable and for the most part it functions perfect except for it still drags and I’d need to up the idle just a tad so it doesent die turned off and warm it pushes perfect in 1st gear with the clutch pulled in

Calum, totally agree!

@2stroke4smoke Glad you solved it. Generally there is no reason to worry about timing on a stock two stroke. Naturally if it's been modified...

Never really looked into it to be fair. The load on the gudgeon and small end probably is not that great when compared with the crank pin. I'd ensure you use the small end for that gudgeon. And never reuse gudgeon's and small ends, for their cost they are jut easy to renew.

@declan Spa Motorcycles Cheltenham will do it though. http://www.spamotorcycles-cheltenham.co.uk/

@irongamer727 PJME.

Yeah it's usually a sign of water contamination. Due to the localised pressurisation of the water pump, it's possible for coolant to leak into the gearbox, without the oil going into the coolant.

@declan no the whole aluminium bit snapped in half

@declan @Irongamer727 thanks mates, will look into that

@irongamer727 well, tap water has minerals in it which will be deposited inside the coolant jackets as time goes. This can affect the cooling. Also iron parts may catch rust as well. You may have to flush your cooling system more frequently compared to using distilled water.

@oldman Any help is amazing bro! will see how it is tomorrow and go over some of this stuff

My wr200cc/dt125r hybrid engine runs with lid cut off. I ran it also with the 125 engine. You just need to jet accordingly.

@ninja As a general rule of thumb, the greater the compression ratio the lower torque spread but the greater the peak power. I don't know the figures, but I'd look to go with a domed head.

All depends why reboring it, if the cylinder measures size you say then never been rebored. The cylinder on your year although called 56mm is actualy 55.95mm, if the cylinder is not damaged then just get it honed. If honing the cylinder then this piston is what you need. https://www.ebay.co.uk/itm/Yamaha-DTR125-DT125-R-DTR-125-56-25mm-Bore-Namura-Piston-Kit/292513505226?hash=item441b29dfca:g:jyEAAOSwwbdWQwnA Whatever size piston you buy whoever is reboring it will bore and hone to match what piston you supply. The best reboring is done by Karl at KPM as had them do a few and also by PJME. Karl charges £30 for a bore and hone with return postage at £10-16 postage depending on courier and insurance required. He will also fully port your cylinder for £100, just have to tell him what your after like more midrange etc or more mid and topend like a YZ. http://www.kpmotosolutions.com/

The DT has now undergone a kickstart conversion! Feels so cool!

@sgt-robuck-5 doesn't work like that. Air pushes coolant up in the expansion tank filling it and then spits out on the road. Then returns to normal once cool. Just open the radiator cap and bleed it, problem solved.