Gate Starts

Being on an 85, weight distribution will probaly be towards the back of the bike. I suggest sitting just behind level of your footpegs and with your torso, lean up over the fuel cap. Gearing will depend on what gear you use to do on a start. 2 gear is the most common.
Im sure you would have done the odd start before, even just in practice, so im sure you would know what footing you will have, as everyone is different.
Now for the little secrets...

one secret is to ease the front brake in on the starting line, and ease the clutch out a little to take out any slack in the chain and lower the front of the bike a little. Remember to release the brake when the gate drops!

Being on a 2-stroke, clutch control on concrete starts is vital. Dont fan the clutch off the start and dont drop it either. You want to count to four, one having it it, and four or the way out. count 2 and 3 are for letting the clutch out. When you get the hang of this you wont have to count in your head, as you will sub-conciously do it.
On dirt or grass starts, then you can ussually release the clutch alot more violently. A good weight position for dirt starts is to be sitting near the fuel tank with your head over the cross bar.

When you at a start, keep reminding yourself that you want to win, and that you deserve a win. When the gate drops, and your into the first corner, push it. Break that little bit later then you normaly would, everyone else wants that holeshot, so your going to have to fight for it. A hint to carry more speed through the first corner (which is pretty flat) is to look either at the exit of the corner or on the straight after the corner.

Line selection on starts can be vital, as you want a nice line into the first corner where you can carry plenty of speed but still not get bottle necked. Watch other races and see who is getting the holeshots, and where they are starting from.

there is ussually a few little cheats to starting gates. sometimes they viabrate just before they drop, sometimes a pin drops before the gate drops, or if your sneaky, go beside the starter's box and look into their box when the 5 second board is up. Sometimes you can see them drop the lever for the gates, resulting you getting that faster leap on everyone else, ussually resulting in holseshots.

Alot of people say not to look at the gate when it drops, look past it. My personal preference is to look at the latch that is holding the gate up, and as soon as the gate drops, i push foward and when i hit the dirt, move my torso back a bit further to gain more traction. Once the gate drops, look well ahead into the first corner and squat a little on the seat if possible to allow the bike move under you. Looking ahead will prevent sliding out on the start.

One last hint to help you get that lead, is to start your bike as late as possible, as this will help hold compression which will give you more power.

if you have any more questions, just ask!