Another bogging issue.

[Guest]

I have an 83 gr650. The bike starts up and idles easily without the choke, cold or hot. The bike pulls hard until hits around 3500-4000 rpms in any gear and it will bog down as if it has no more power. I'm only assuming this is a fuel issue but I can't seem to figure it out.

I installed a clear fuel line to make sure the carbs were getting fuel however I do not see any fuel when I turn the petcock on. Without the fuel line attached the petcock does flow freely. Maybe I am used to dirtbikes and their gravity fed systems but I would assume that I should visibly see the fuel in the line after turning the petcock on.

[850 Combat]

The petcock is vacuum operated. No manifold vacuum, no fuel flow.

Beyond that, the CV carbs are super sensitive to vacuum including inside the airbox. Bogging like that is a sign of vacuum leaks upstream AND downsream of the carbs, and also a sign of clogged or partially clogged pilot circuits in one or more of your carbs.

Have you taken the airbox off?

[cootees]

No, the airbox is still on the bike. Could a bad filter cause it? A mouse had gotten into the filter while the bike had been sitting at the PO's. So chunks of the filter are missing.

[jbthomp]

You need to get a new filter for that thing regardless. You will ruin your engine in a hurry if pieces of it are missing. Check for vacuum leaks with propane or mapp gas. Everything in the intake on both sides of the carbs has to be in good shape for the engine to run correctly. Also if it is bogging like that it means you are running lean. Thats not good for valves and pistons.