Tuning issues.. Jake can you advise?, advance curve or jetting (that is the question) |
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Tuning issues.. Jake can you advise?, advance curve or jetting (that is the question) |
brant |
Jun 9 2009, 12:52 AM
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914 Wizard Group: Members Posts: 11,632 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
I finally got my latest project running but not well enough
I need to do a little tuning... its a 1.7 motor with a cam (don't know the specs of the cam) from the previous owner I can get leak down/compression, but don't have them at this moment. I also don't know the compression, but it is mild... probably stock the P.O. claims it was rebuilt and I believe it I took all of the tin/push rod tubes off, and it looks to have been rebuilt with out worn/shot stock cam lobes and with lifters showing no significant wear doesn't seem to burn-smoke or leak any oil at this point. Its running 40mm dual webers, currently testing at 3300 foot altitude (motor came from a running car at about 5500 ft) I rebuilt the carbs and the jetting is: -28mm (chokes) main venturis -2ndary venturis 4.5 -main jets 115 -air jets 200 -emulsions F11 -acc. pump ball jet 50 -acc. pump towers 50 -idles 50 I've never carbed a 1.7 before The motor came with a 009 distributor and points I ditched it and put in a L-jet 914 (1.8) distributor with points, blue coil, and no retard/advance lines hooked up the cap/rotor/plugs/wires are all good-new car idles smooth, pulls fine from standing, and then stumbles mildly from 2000 - 3000 the car clears out and runs great at 3000 or 3100rpm timing is currently set at 29degree's, but this is my norm for altitude. dad and I are in disagreement about the cause he thinks its too rich for the tiny motor I think its a distributor curve issue Jake, do you know? I have a Djet distributor available easily... or could put the 009 back on... or think maybe I should buy an 050 somewhere to see if the curve is actually the problem We discussed buying 110 mains also to play with it... thanks in advance for any advice from the guru's out there brant Attached thumbnail(s) |
tat2dphreak |
Jun 9 2009, 01:32 PM
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stoya, stoya, stoya Group: Benefactors Posts: 8,797 Joined: 6-June 03 From: Wylie, TX Member No.: 792 Region Association: Southwest Region |
I'm no where NEAR the guru Jake is, but your carb specs are similar to my 2056... which I got the carb-tuning for from jake...
I'm running 32mm vents, 125 mains, f11 emulsion 60 idles 200 airs that is what jake suggested for a stock-cammed 2056.. I agree with McMark, I'd maybe kick up the vent size and mains. I'm guessing 30mm, and 125 mains because there's a 'gap' in between your idles and mains right now... I THINK you can either increase the idles or mains to fix your issue, you might want to do both in a smaller increment tho... gaps are bad, if I understand it right, you are stretching the limits of what the idle jet can put out, so it cuts to a lean mix, then you get a lean mix starting the main jet, so my thought is if you increase both a little, you should get a smoother transition because the idles aren't being stretched as much, and your mains should start a little richer... meaning no 'lean' gap. I could be off the mark or over simplifying it tho.. |
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