DT125R FORUM

@calum I will definitely recheck that next time i´m working on the bike but as far as i remember these bushings only had some slight axial play and no mentionable radial play as seen in the video.

@calum I realy appreciate any ideas and experiences.
The dampers in the clutch basket are worn and there is some play in it but the noise does not seem to come from the right hand side.
I have assembled the clutch according to the manual as well so this should be fine.
For me the noise seems to come from the left hand side of the bike but I am not sure if any part of the starter clutch or flywheel could make a sound similiar to the one in my video.

@calum Thank you for your answer. Yes I´m confident that the balancer shaft and crank align proper acording to my repair manual. On my engine there is one mark on the cranks gear and and one on the balancer shafts gear and these are aligned correct. I think they can only be alinged in 1 position because of the keyweys and the 1:1 gear ratio but please correct me if I´m wrong here.

@spookdog That´s not impossible since its my first two stroke bike and I normally drive a 600 ccm 4 cylinder which runs way smoother. I don´t realy know how to describe the sound but I think ringing wasn´t the best word to describe the sound. It is most audible to me from around 0:08-0:15 when the engine is decelerating and to me it seems to have the crank RPM if it is a rotating part so probably nothing gearbox related. But it´s good to hear that the engine sounds normal.

Hello,

First of all I want to thank everybody for your constructive answers.
sadly i hadn´t had time for my project bike this summer. After I checked the piston size it was clear that the loud ratling was piston slap because the clearance between bore and piston was around 0,09-0,1 mm instead of 0,05 mm. So I got a new piston that fits the bore of my cylinder, installed it and the bike ran way smoother. But after around 200-300 km I realized a new sound coming from the left side of the Engine. I uploaded a video: https://www.youtube.com/watch?v=Qj7QRH6IZOc

I hope somebody has an Idea what this ringing sound could be. sounds like a bad bearing to me but all bearings were replaced like 350 km ago and when changing the piston the big end bearing and the main crankbearings had no radial play at all. I think the sound is coming from the left side of the Engine. Also I´d like to note that the clutchbasket has some play but the sounds doesn´t seem to come from the right side of the bike. except this noise the engine runs great and it seems to have good power as far as i can tell because i have not been reving higher than 6500 rpm.

@spookdog So I had the Flywheel cover off today and and the starter overrunning clutch seems to be ok. Also there is no play in the mainbearings and there are no oil leaks at all. I think I´ll take of the cylinder tomorrow and check the small end bearing. the noise only appears when the enginge is decelerating and not on tickover.

@madgyver haven´t checked the headgasket yet cause i didnt want to take it apart if i dont have to and hadn´t had time to check if the PW Play is the reason for that sound. If that sound does not come from the powervalve play i´ll have to take it apart. I took a 0.8 mm cylinderfoot gasket I think, and the head was straight, it wasnt planed, so there should be enough squish gap but please correct me if i took the wrong gasket or did something wrong here. I think there should be enough space but i´ll check all solution approaches this weekend and I´m so grateful that ya´ll have so many Ideas what could be wrong. I will give an Update this weekend. All dowelpins are in place and all bolts were torqued to spec.

@spookdog My Engine sadly only has an E-Starter.
@DTR+NSR I´ll try that as soon as my new battery is there.

I just checked the Powervalve and it has some axial play but i cant feel any radial play. The Piston and Powervalve have no marks at all. It is my first 2 stroke Engine and I dont realy know if this axial play could cause the noise. Does anyone else have axial play in their powervalve and experiences rattleing?

@declan thanks for that fast reply. The shop that honed the cylinder said that its not necessary to maschine the powervalve because it should fit with 56.25 still and there wasnt any visible overhang into the cylinder. also they sent me the piston with the correct size as far as i know but i´ll have to check that again i guess.

Hello,

I have just rebuild my entire engine. All bearings and seals were replaced, the cylinder got honed to +0.25, got a new Meteor piston and the crankshaft got a new rod and got straightend. The Engine seams to have no leaks at all and starts up great. The only problem is a pretty annoying ratteling sound when the engine is decelerating. The clutch does not affect this sound also it appears when i m in gear and the clutch is pulled. Its exactly the same sound as in this Video:
https://www.youtube.com/watch?v=pbfH93HpAto

Do you have any Ideas what could cause this noise?