KE70+AE92 Posted May 12, 2008 Report Share Posted May 12, 2008 i read somewhere that the original carby on the 4k it has two butterflies and one opens when u push down the accelerator and the other opens at high speed if thats true is there a way to make that both open at the same time? would this mean that i would have more power at lower rpm thanks Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted May 12, 2008 Report Share Posted May 12, 2008 What you are referring to is 'Vacuum secondaries', and NO stock 4k carbs don't have it, they're mechanical secondaries. With most vacuum secondary carbs, its only a matter of a strategically placed cable tie or 2 to lock it up and have mechanical secondaries. Very common on Gemini or mazda Nikki carbs. Quote Link to comment Share on other sites More sharing options...
Felix Posted May 12, 2008 Report Share Posted May 12, 2008 (edited) The stock carbs have a "high speed valve" in front of the secondary butterfly. It is a weighted butterfly, which does give a vacuum secondary type effect. The problem is that the stock carbs don't have transition circuit on the secondaries like webers do. You might find that you end up with a lean flat spot. An easy experiment would be just to tie the high speed valve open and take it for a drive. Edited May 12, 2008 by Felix Quote Link to comment Share on other sites More sharing options...
Guest Sbox Posted May 12, 2008 Report Share Posted May 12, 2008 (edited) Deleted Edited May 24, 2008 by Sbox Quote Link to comment Share on other sites More sharing options...
coln72 Posted May 12, 2008 Report Share Posted May 12, 2008 Give it a go. I actually removed the "vacumm" butterfly on one of my carbies and it had no noticable negative effect. Can't say that it made any difference either. Quote Link to comment Share on other sites More sharing options...
Guest Sbox Posted May 12, 2008 Report Share Posted May 12, 2008 (edited) Deleted Edited May 24, 2008 by Sbox Quote Link to comment Share on other sites More sharing options...
Felix Posted May 12, 2008 Report Share Posted May 12, 2008 No, coln72 is saying he removed the extra weighted butterfly (high speed valve) that sits above the secondary butterfly. Quote Link to comment Share on other sites More sharing options...
KE ping it real Posted May 12, 2008 Report Share Posted May 12, 2008 Just buy a cheap second hand 32/36 weber and be done with it Quote Link to comment Share on other sites More sharing options...
Guest Sbox Posted May 12, 2008 Report Share Posted May 12, 2008 (edited) Deleted Edited May 24, 2008 by Sbox Quote Link to comment Share on other sites More sharing options...
KE70+AE92 Posted May 12, 2008 Author Report Share Posted May 12, 2008 well my car idles a 1500 to 2000 rpm its doing it because the choke gets stuck open a bit when i push down the accelerator i have to manual go and close the choke so it idles properly but i will try keeping one open and see i it has any affect thanks Quote Link to comment Share on other sites More sharing options...
Guest Sbox Posted May 12, 2008 Report Share Posted May 12, 2008 (edited) Deleted Edited May 24, 2008 by Sbox Quote Link to comment Share on other sites More sharing options...
KE70+AE92 Posted May 13, 2008 Author Report Share Posted May 13, 2008 Is only been doing it lately my carby started stuffing up before and would stay at 3000rpm and wouldnt go down my grandfather had to take off the carby and fix it i think one of the butterflys or something was stuck open lately it just stays at 1500 to 2000 when i look at the carby the choke is closed just a little bit so i open it fully and it idles properly but when i rev the car it goes back up and idles at 1500 to 2000 Quote Link to comment Share on other sites More sharing options...
Felix Posted May 13, 2008 Report Share Posted May 13, 2008 Check the linkages like Sbox suggested. Sounds like something isn't setup or adjusted right. Quote Link to comment Share on other sites More sharing options...
Guest Sbox Posted May 13, 2008 Report Share Posted May 13, 2008 (edited) Deleted Edited May 24, 2008 by Sbox Quote Link to comment Share on other sites More sharing options...
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