I got someone to snorkel my 350 Yamaha grizzly, and when I get some speed(30-35mph), the engine bogs down, then goes to normal. I have three snorkels, not sure why, but I know one blows out heat, another takes in air, and the last one I don't know what it does. Whenever I get speed I think the snorkel that takes in air isn't getting enough air so it bogs, but I'm not positive. If anyone knows how to fix an issue like this please help! The snorkel uses 1-1/2 PVC

 

I've seen other snorkels using bigger tubing. Maybe yours is just too small.

 

The one blowing hot air is the exhaust for your belt housing one of the others should be the air intake for the belt housing and the last is your air box intake. Most likely the guy did not re-jet your card so it has to much air for the main jet and bogs down. The main jet should be about 10 over the stock main when you snorkel a quad.