I installed a Dynoport silencer on my '01 renegade 800 and now I am having trouble with hitting top speed, it bogs at about 7,000 RPM. Could this be caused by the gearing of the Renegade?

Try putting your stk can back on and see what happens

I put the stock silencer on and it runs fine, pulls strong through the power band and revs quickly. The silencer is going to put on e-bay $125

common problem on the doo's they hate most cans especially mbrp. if you want to play with the exhaust at all it has to be changed to either a good single or twins. the cans change the high rpm power for some reason, i believe it is due to clutching.

Some silencers cause the eng. to run cooler. This would cause you to go down a few jet sizes to compensate. If the RPMs are down at full throttle with silencer on than it means its producing less power.