hey guys,
I have a an 85 Honda saber 750, the bike runs but revs up and down a bit on its own. the bike will also not run unless the choke is on. Any help would be great.

Mark.

I don't have much experience with street bikes yet, I just got an 85 Nighhawk 750 so I'm getting to know them, but most of my knowledge comes from 2stroke dirt bikes.

It sounds like you may have an air leak somewhere, the surging idle is usually an indication of that, plus having to run the bike with the choke means you have to be giving it more fuel, which also seems to fit with the extra air coming in.

On dirt bikes you can spray WD40 on the engine while it's running and if the idle changes when you spray in a certain place that will indicate your air leak.

I don't know if all of this applies to street bikes, hopefully someone else can confirm it?

that would work evsuper. my suggestion is to look for any cracks, loose clamps, ect from between the air intake and the head.

it wouldnt hurt to clean out the carb either

Ok thanks guys, the carb is spotless so I'll check thouroughly for any cracks or air leaks.

The early Honda V4's were know for cracking intake boots. That is where I would start to look. The spray on the  boots works. An unlit propanr torch works also if you don't want anything liquid sprayed on the engine.

Ray