A gift is only taxable if the giver has gifted more than $5.4 million during their lifetime. This is the amount of the lifetime gift and estate tax exclusion. And there is some talk about eliminating the estate tax altogether in the current tax reform plan. Unless you have given more than the exclusion limit, the gift must be reported but no tax is actually owed.
If you are the part owner of the property when it is sold, and the IRS figures out what you are doing, they will assume that you are a 50-50 owner and that you are responsible for the capital gains tax on 50% of the gain. Your mother can exclude tax on her 50% of the gain, but you cannot exclude tax on your gain. Simply directing that the check be made out entirely to your mother might impede the ability of the IRS to detect what is going on, assuming that the closing agent goes along with it, but it does not make it legal. And you may find that the closing agent will refuse to go along with it.
If you quit claim deed your share of the home to your mother before the sale, then your mother is entitled to a $250,000 exclusion, and if she files jointly with a spouse, they are entitled to a $500,000 exclusion even if his name is not on the title.
You may want to discuss this with an attorney or tax advisor. But what it sounds like you are planning on doing is likely to be viewed by the IRS as fraud if they catch you.
