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Which Is My Vacuum Advance?

Featured Replies

4K-C. Stock carb.

 

I'm finally getting around to sorting out my idle and power problems.

I changed my plugs and leads. No change.

 

I went to town with carby cleaner - now my idle sits at around 3-4k.

I have tried playing around with my idle mixtures and dizzy.

 

Then I noticed that there was no Vacuum Advance coming off my dizzy.

 

Tried to find a decent enough diagram to work with but couldn't find anything.

 

Will reconnecting the V-Advance bring the idle speed down?

 

Located on the Gold Coast if someone wants to come give me a hand for hugs/beers?

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Edited by B-Lugg

  • Author

No idea why the photos flipped!

  • Author

Thanks mate.

 

VA all done.

 

Timing is wasted.

Hi Ben,

The vacumm pick up point for the standard Aisan carby, is in the lower inner side of the carby closest to the rocker cover, poking out from down near the carby bowl, directly under the fuel line in union on the carby. Get a meter of 3mm or 4mm rubber vacuum tube from SCA, and connect to carby & dizzy. Make sure they are a tight fit. (small plastic cable tie ensures that)

 

Start engine & see if that lowers the excessive idle speed. If it is still too fast, undo slightly the bolt holding down the clamp for the dizzy & turn very slightly & slowly clockwise. If your problem is excessive advance, then this action will make a big difference.

 

I'm assuming you've set the throlle idle stop as well as the idle mixture.

 

Let's know how you go.

 

Cheers Banjo

  • Author

Hi Banjo,

 

From what I gathered on the diagrams the vacuum advance was on the chassis side of the carby?

 

After playing around with my idle mixtures and the timing on the dizzy, I finally managed to get it running and idling decently, however it's still far from perfect. I'll probably do a lead, coil, points and plugs change and see how that goes.

 

Another thing it might be - Do 4K's have PCV valve from factory? because I did rip that pipe out and put a mini cleaner on there, so that may also be affecting the idle?

 

Cheers.

Sounds like a vacuum leak perhaps. Try lighting a sigarete, blow some smoke or just hold the siggie in one spot. around carby and manifold while its running and see if smoke it attracted to one area.

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