Topic: Issue with sticking throttle on CR 31's

[voxonda]

Since mounting the CR31's on the bike and running on the bench there is a issue with the throttle. When engine is off, throttle action is light and everything looks to be in good order, but when the engine is running it looks like the throttle slides 'stick'.  Action is much heavier and it does not return easy. Set is new, cables as new. Anyone familiair with this:


Thanks Rob

[teebee67]

Rob,are they old carbs, I had the same problem on a 350 K4 Honda. If the carb bodies are worn they feel ok without the engine running, start the engine and the suction causes the slides to tilt in the worn bores causing them to stick. I cured it with a new pair of CR31 s. On a 750 with new CR31 s I had slight sticking  problems when using a single cable, changing to a push/pull type cured it and made the throttle action much lighter.

[voxonda]

These are new carb's with push and pull cables. Like in the article from Keihin it can be due too strong negative pressure from the engine, which in its turn is a good sign.

[MRieck]

These are new carb's with push and pull cables. Like in the article from Keihin it can be due too strong negative pressure from the engine, which in its turn is a good sign.

My though Rob. I have replaced the return spring with a stronger piece.

[bwaller]

Pull a plug Rob.

[turboguzzi]

rob, sounds to me like you need a cam with more overlap

[voxonda]

Thanks guys, so minus one plug and more overlap. Okido it is a start......................................................