tire size to gear ratio qusetion

[DJ250R87]

I have a 88 honda 250r with the stock gear ratio and stock tires on it i have some bigger holeshots for it but i cant remember the size of them anyway it seems slower with them on it and i cant use 6th gear when there on it where would i start to change the gear ratio. front sprocket, rear sproket, or both?

[Wacko Jacko]

go up a few teeth on the rear sprocket, or down 1 on the front

[DJ250R87]

thanks i will try that