DT125R ARCHIVE

This is actually starting to do my nut in.

Can anyone help with this please?

Basically there is lots of contradicting informaiton out there on the net with Standard Piston Sizes for different codes of barrels.

For Example directly from the Haynes manual:

Cylinder barrel

Standard bore ID:

     TZR and early DT models (3DB1)....................... 56.40-56.42 mm

     Later DT models (3RN1 Onward)....................... 56.00-56.02 mm

Piston

Standard OD:

    TZR and early DT models (3DB1)......................... 56.34 -56.40 mm

    Later DT models (3RN1 onward)......................... 55.950 - 55.955 mm

Ok so that above is directly out of the Haynes.

So what is with the different internal Diameters of the earlier models. What was the code on these barrels. I'm mainly concerned with the DT side of things.

So from what I have read is that the 3BN cylinders have a 56.40mm Internal diameter. And that the 3MB cylinder is 56.00mm ID.

I've recently acquired a 4FU cylinder and will be looking into fitting it onto the DT bottom end. Can't find much information on the net about it's specs. Only that the bike was coded 4GW and that the cylinder is off a 1993 TDR. But what does that mean?

What I want to know is what is the standard piston size for the 4FU. i've measure it using verniers and all I get is the 56.00mm ball park. But how accurate am I measuring?

When looking for pistons on the net Woesnner reckon that the standard bore sizes are the same for my 1993 TDR and the DTRE

Any help is appreciated. At least here it will remain for future people to refer to...