qt50 bogs down

just acquired 2 qt50's neither running

cleaned carb on one of them

replaced sparkplug

fuel filter

oil change

aftermarket cone style air filter

it is rideable and it will run ok and idle, when throttling up about halfway it just starts to bog down and never really seems to get to the powerband, ive tried adjusting the mixture and it doesn't really change anything sparkplug is gapped to spec...any ideas?

Re: qt50 bogs down

The first thing I would do is take the air filter off and try it again to see what happens.

Re: qt50 bogs down

no change with filter removed, anyone know what the compression spec is?

Re: qt50 bogs down

Based on searches that I have done in the past in here - I've seen compression numbers ranging from 105 psi to 145 psi. I wouldn't trust my Harbor Freight gauge for accuracy, but anything north of 100 psi would normally be a motor that can be at least started. With my QT I ended up replacing the original top end out of precaution because the bike is almost 40 years old. $40 and 20 minutes. Once I had established a good compression, I chased down some fuel issues (had to use a clone carb). If it hasn't been done, you probably need to replace the crank seals. Easy job if you have the tools.

I've been down this path with other bikes (four strokes) and most recently with a QT50. There isn't much to these QTs and parts are accessible and relatively cheap. Lots of great info here: http://qt50.net/

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