I'm driving an 87 fourtrak dx that has recently taken to drinking petrol like it was towing a Sherman tank. The rev's also now take far too long to drop between gear changes, and the idle keeps changing like the weather.
I suspect a small (vacuum ?) type pot attached to the front of the carb may be to blame as it takes a long time to drop, hesitates long enough to keep the idle high then eventually pops out fully allowing the idle to return to normal.
My question is...are my suspicions right and if so can it be sorted out, or do I have to track down a new item?

Would appreciate any advice you can offer.