Sound recording of engine prob DT 125 <FIXED>

[darkangel]

Before i book the bike in with a mechanic i would like it if someone could listen to two recordings i made of my engine.

They are in a zip file, two sound files and a txt file explaining what possition the mic is in when recording are inside it.

Here's the link

https://www.megaupload.com/?d=UOKEUEIU

The bike is a Yamaha DT 125R 2-stroke
12k miles on the clock

I dont know how well you can hear the problem on the recordings but basically there is some kind of strange noise comming from my engine around the barrel area, it does not effect performance but it is lound and annoying.

Any ideas what could be causing it?
Thanks

<UPDATE>
I had a rebore done, clearances are so tight now compared to what they were before, i had troubly getting the piston and rings into the barrel the clearance was so small.
The sound is (all but a tiny noise, probably just the noise of an old engine, doesn't bother me) gone now, performance is up noticably, fuel economy up a bit, a new gasket also solved my coolant leak problem.
So.. if you ever have a bike that has the same problem as what i desribed then you know its either or a combination of failed rings/piston slap due to excessive clearance by putting a pattern piston in a standard bore.

[hmmmnz]

did not listen to the file, but,
just pull the head off the bike,
its only a few bolts and then you'll be able to see the piston and barrel, and the top ring and check for any damage,
____________________
the humans are dead
I kick arse for the lord
Wiring Diagrams BIDNIP it bitches

[darkangel]

i have taken them off they are fine.
I did a top end rebuild in the past 1k miles and had my barrel inspected by a yamaha dealer which they said it was "ok" and apparently didn't need a rebore.
Just checked the flywheel and could only find the most minute play in it (really really tiny, not visible), it doesn't sound like the noise is comming from there anyway.

I put a screwdriver upto many parts of the bike and it sounds like it is comming from the cylinder head, i know i have a leaking head gasket and probably need a head skim but surely it would not cause such a noise.
I dont want to take my head and barrel to a dealer to find out that the noise is still there afterwards and i dont really want to have to take my whole bike there as its my only transport when the answer could be really simple like piston slap.

[willi]

we cant hear the recording unles we install that megaupload crap
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

wat goes around comes around.

[willi]

flange gasket leaking??
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

wat goes around comes around.

[hmmmnz]

[lukamon]

ANY play in the crank bearings means they are gone. the more you ride it, the louder it will become until eventually it sounds like a tractor. (this just happened to my kmx )
____________________
killa wrote: Im an ass man myself

[darkangel]

ill describe the play in the flywheel.
i check for up/down play, none
i spin it a bit and check for up/down play, none
at some random spot however if i push hard upwards on it i can hear a faint noise like it moves, cant see or feel any movement though

If i were to have the engine fully rebuilt by a mechanic how expensive would it be? considering a full rebuild is only 200 pounds if i send it to stan stephens

[willi]

sounds like piston slap to me. who measured the bore? did they take the measurement from the top of the cylinder or the bottom?? a cylinder will wear at the top more than the bottom like a cone. so have it checked again. 12000 miles is a lot for a two stroke of that size.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

wat goes around comes around.

[darkangel]

THANK you will for listening to the file, yeah it really wouldn't suprise me if i did need a rebore.
They were busy at the time so took it into a room and had a quick check and they suggested a hone for it but otherwise said it was okay.
didn't get it honed though

[darkangel]

hang on. just remembered i stripped the barrel not long ago and there was a fair but of blow-by on the new piston
+1 for it being piston slap?

[darkangel]

any other opinions?
I just snapped a clutch cable last night which was fun trying to get home with... so my bike will be off the road for a few days anyway.

does anyone else know if it is piston slap?

it makes the noise heard in the sound files
There is quite a bit of blowby discolouration on the piston between the top ring and piston skirt
and you can hear the noise allot on decelleration

Also would a yamaha dealer (it has an mot place underneath) have the tools for a rebore, a head and a barrel skim?

and if i were to have a rebore should i go and get the max rebore so i can get some performance gains? im not intending to keep the bike for too much longer would a 1mm oversize increase power much?

[willi]

if your not going to keep it much longer just save your money. keep riding it. the worst can happen is it will blow up, and you will have to get it rebored.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

wat goes around comes around.

[darkangel]

i want to be able to sell it though, and nobody is going to buy a rattling bike
I want to keep it for atleast another 4 months for me to save up some money for my full test, new bike and insurance

[darkangel]

bike has also been difficult to start lately, requiring the throttle to be opened