I have a 1978 Yamaha dt250 that I use for ice racing someone on here once gave me a ratio and I’ve since lost the number and haven’t ridden in almost 2 years taking the bike out this weekend but I need to mix some fuel can anyone help? Thought it was 32:1 but for some reason I remember someone saying 20:1 if you are racing. 

Depends on oil you're using and conditions... racing is obviously much harder on engine than cruising. Numbers you gave sound right for basic two stroke oils like Yamalube. Nobody wants to give you bad advice and have you break your toy...

You just aren't giving enough info to get a good answer and "oil threads" sometimes tend to degrade into heated "political" type exchanges on forums. Most people avoid oil threads like the plague.

Different premix ratios can also affect jetting slightly... so if you have bike tuned to the edge for racing, changing oil and/or mix ratio can require rejetting.

Oil bottle or oil manufacturer website should have ratio guidelines as well... I'm a fan of "more oil" so if oil was rated to mix at 20:1 and I was riding hard that's what I'd do.

Some high-zoot synthetic oils shouldn't be mixed that rich... they are designed for 50:1 or leaner... but those boutique oils are also generally designed for more modern water cooled engines with different requirements than an old air cooled Yamaha so I personally don't use them. Others swear by them.

I'd run 20-1 on an older motor running hard for long periods under load. Digressing back to "86 i ran 40-1 with Castrol TTS in my new KX125 but had a Nikasil plated cylinder so not really relevant.
We'd love to see a video sometime if you can organize one. Thanks.
ps, Mark mentioned jetting which i must admit i hadn't thought about. Back to my KX, i squeezed a bit more comp out of it in "87 when 12 months old so increased the main jet a size by one i think & might've raised the slide needle a notch & responded well on a fast rolling flowing circuit.

Thank you for the response I do have videos and photos I tried to attach to post but I couldn’t get it to work! this is far from a fine tuned racing machine but dang it is it a blast to play around on the frozen ponds! Still very new to the forums but I will get a video or picture posted! 

Yes pic thing isn't working so others say use 'imgur' & i'm using google photos i believe--"i muddle through"--& i use youtube to link videos. I'm old & technicaly challenged haha so can't be too hard for me to work it.