DT125R ARCHIVE

Yes Please mate it would be a big help. I was on the phone to my brother and told him that id oiled the top on the piston and he said its not ment to have any oil on the top of the spark wont fire up the bike as the oil stops it from sparing with the piston. so gonna have to take off the head again and wipe it clean then put the head back on and try again. Thanks for your help.

Yeah tried to bump it but when i pull the clutch in it's still in gear? the cable still moves but just stays in gear when I pull the leaver in. But put it in nutroll and then kick it in gear and still wouldnt start. Now when i kick it with the kick start it sounds rough.. I can't believe that ive done eveything the manual says but I just cant get it to start.. So it's going to the doctors on thrusday next week to have it looked at. I know it will be at least £200 odd. Fu**ing Gutted. I have no idea how all of you guys manage to get it working again. Bloody angery and pissed off.

here we are i put a little video up on youtube of my bike when i try and kick it over.
http://www.youtube.com/watch?v=jKMOf5YmcdA

sounds pretty stiff in there u got the right piston and put the rings in the right way round ?

has it just been rebuilt ? if so did you check the big end on the crank ?

Hi and thanks for all of your replys. The piston has a arrow on it -> I made sure it was facing the front wheel. I took the piston back to the bloke and he put the rings on the piston for me for free so i know they must be right. put 2stoke on the barrel and not sanded anything and put 2stroke on the piston wall and rings. cleaned the head of the piston to make sure it get the pure spark. The crank only moves a little side to side cant pull up or down. i dont have any easy start or break cleaner but am gonna take off the spark plug and see if i can see petrol going in.

check a spark

then look for water on the plug

then , make sure compression

and put fuel in the barrel, if it still doesnt start dunno

Yeah i looked at this the other day. Had a good spark no too sure where the coil is? the piston is 0.25 oversize so would that be anything to do with the gasgets as i guess there standard size as i bought them off ebay. When i put my finger over the hole yesterday i could feel the compression push out and as the piston goes down i could feel it suck in as well. wouldnt mind taken off the head an look down the barrel to see if i can see anything catching or see if i can find out why it's sounding jammed in there when i use the kick start. maybe even take off the barrel and put it back on and see if it makes a diffrence once re seated. Ive had the topend off twice now and every time ive put it back together it's wanted to start but never has.

Just thought id ask do i need to bolt on the cylinder on in a criss cross patten?

ok got the head off and its not making that sound and seems to be nice and smooth with the head off. Gonna unbolt the cylinder and re bolt it up again and see what we get il take a vid and pics. Let me know what you guys think. Thanks for all your help guys.

the piston seems fine going up n down there, but u got way too much sealant on there m8, thats gonna go every where when u bolt it down , alot of it will go into the cylinder aswell , best go get another gasket m8 otherwise urll be taking it all off again

Just out of interest, how many times did you take the head on and off? And did you replace the head gasket every time you did it?

The head gaskets for these engines are like a one use job really, because you compress the gasket when you fit it, so if you had fitted everything, found you had a problem, took it off and re-fitted it with the same gasket, you are going to be running around in circles essentially, as that gasket will be knackered.

 

Edit: the pictures didn't come up the first time I looked, just seen the pic with the instant gasket... fail lol. Its a proper gasket or nothing mate, you can't use instant gasket!!

-- Edited by mammoth200 on Thursday 5th of May 2011 12:37:12 PM

Old thread :\ For future reference.

You still have gasket paper on the cylinder and head! That must be scrubbed clean otherwise the gasket won't sit flush!!!

ALWAYS ALWAYS ALWAYS use Genuine Yamaha Gaskets purchased from a Yamaha Dealer! ALWAYS I can't stress that enough. Would be worth a shot skimming the head and cylinder although that won't affect the starting of the bike. Also the YPVS won't effect the bike starting unless its completely shut! Could have tried pinning the YPVS open and disconnecting the server.

Is the spark intermittent?

If so then it could be the side stand switch!

This occasion the bike sounds rough and I would check for compression. You said it was an oversize and I would make sure that the correct piston was installed.