CB175 revving randomly

[legitmw]

I recently came into a CB175 for cheap. A new battery and a petcock cleaning and now it starts right up and runs. Except it will randomly rev up really high for 10 seconds every 45 seconds or so. Then it will go back down. The throttle isn't sticking. I wont' touch the throttle and the revs will still come and go. If I put it in gear and let out the clutch while it's revving, it will tone it down and when the wheel is fully engaged and I start rolling, it will stop revving up. I'll ride for 30 seconds and after grabbing the clutch several times, I'll grab it again and it will rev up like crazy.

I can't think of what could be causing this.

 

[Barnburner]

Check for air leaks around the carb manifolds and the boots to the air filters

 

[jungalist]

sounds like the engine is sucking in false air, i assume because it revs that high the leak will be somewhere around the inlet manifold, not the air filter

 

[legitmw]

Fixed it! Turns out it wasn't an air leak, but the throttle cable was improperly routed. The revving was happening whenever I turned the wheel to the right and it pulled the cable tight against the steering stem.

 

[SONICJK]

Fixed it! Turns out it wasn't an air leak, but the throttle cable was improperly routed. The revving was happening whenever I turned the wheel to the right and it pulled the cable tight against the steering stem.

Always nice when it's something simple eh?

 

[legitmw]

Always nice when it's something simple eh?

Yes it is. I think this is the first time I've caught a break too lol. Ususally it's the worst possible thing.