DTR year info and setting for race bike

[supermoto1962]

Hello

Which of the Guru's of the DTR can help?

I have a DTR with the following markings:

On the PValve side i have these:

Bottom of barrel - 3BM00

On crankcase - 3BN03 with Y-1 underneath

On oil pump side i have this:

Bottom of barrel - Y-1

On the head i have this:

3BN

Y-2

So what year please?

Next the bike is as follows:

DEP front & back

Running premix ay about 50:1

CDI is a 3RM-20

Air filter is standard

Quick action throttle

Carb - i assume is standard

Main jet? Yet to take carb off. Suggest size please.

Power valve - not checked yet

Will update on jet size, carb model and gearing later today.

Off the line the motor is bogging down and through 1st & 2nd it is dog slow. Throttle wide open and clutch dumped when the flag drops. Nearly last off the line .

From 3rd onward it takes off in each gear with only a bit of a flat spot then it flys.

Any information to help get this bike moving will be appreciated.

Could the bogging down be because the power valve has been jammed open?

Please post links to any information.

Thanks