Hi,
I bought a DT125 a couple of years ago, mainly because it looked very sad sat outside decomposing.
I started sorting it back in the winter and now have it almost to a rideable condition, in fact I have had a few rips about on it but have pulled the barrell off to rebore it just now.
I have a few questions which I will ask in a separate thread.
Ray.

@Uber_Beluga
How many wires going up to the kill switch, usually only one and when the switch is closed it earth's out the low voltage side of the coil, so if it is disconnected and taped up it should not stop it from starting.

Can't find 15x25x12 needle roller bearings on ebay but google turns up a few hits for TR152512
You still might be able to get it from a bearing stockist but looks like it is not a common size, if you phone a few you might get lucky, probably be cheaper and quicker than a genuine one.

I wonder if it's possible to remove the generator side cover run it and squirt some WD40 at the crank and see if it makes any difference.
Might try that tomorrow.
Wanted to get the float height set so I could eliminate that, it looks like it is set too high so should be rich if anything.

Sorry wasn't sure where to post it.
Yes, I did wonder about an air leak but It's just been rebuilt with new bearings, seals etc. if it was sucking past the crank seals on the clutch side wouldn't it eat its own clutch oil and smoke? could be the other side.
Don't think it is leaking on the inlet anywhere as it's all fairly good.
My float is like this one http://www.ebay.co.uk/itm/Yamaha-NOS-AT2-AT3-CT2-CT3-DT125-MX175-Float-314-14185-00-00-41-/181056072162
what point on the float do you measure to?

Finally got back to trying to get the DT to run nice but it seems like it is running really weak.
I start it on choke and it seems ok but as soon as I put the choke in it wont seem to hold a steady rev and if I blip it, it wants to rev away madly for a couple of seconds then will die unless blipped again.
It just seems like a really weak mixture, I moved the needle down to one notch from the bottom but it didn't seem to make much difference so I have the carb off to check the float height which according to the Haynes book of words should be 21mm but mine is probably about 18mm - but my float does not look like the one in the book and I can't see where you are supposed to measure to.

How do I post pics on here?

A DT and a defender, a man with taste, not sure about the painted wheel rims though.

I want to know what these little rubber bits are as well because they must be missing on mine.

Put the clutch basket back on and wedge a piece of hard plastic between the gears, i use a small lump of nylon, then it should come undone with a breaker bar.
Or cheat and use an air rattler/windygun.

@Uber_Beluga
So if you have four wires - one will be an ign. Switched live to the starter switch. One will be the return wire to the starter solenoid.
Then the other two will be a feed up from the CDI and a return that either goes back to the CDI to make a circuit or maybe goes to earth as I mentioned before.
Just buzz the wires out with your meter to check what they do, but if you can get a good make/break across the switch then that's not you problem.

@Uber_Beluga
How many wires going up to the kill switch, usually only one and when the switch is closed it earth's out the low voltage side of the coil, so if it is disconnected and taped up it should not stop it from starting.

@Biker_123
How does the clutch arm come out, if you can get the clutch arm out without stripping the box then possibly you could push a piece of wire down the clutch shaft hole and maybe push out the broken bits, I wouldn't use oil in the shaft, I would use a solvent to try and wash out any small bits.
If you still cannot get the broken bits out then it's rebuild time.

@Biker_123
If you push a rod down against the bearing (or whatever is in the shaft) and then move the clutch arm does it move in and out like it's supposed to or is it stuck solid?
If it is stuck solid you will probably have to completely strip to punch the broken bits out.
If you can get a bit of movement in it I would try wd40 or any solvent in the hole and keep moving it to see if you can get it to fall out.
I don't know how the clutch arm is held in but presumably if you removed it you could feed a wire in and push the rod out.