Project Fat Nikki

t_g_farrell · 04-25-2012, 08:48 PM

I put the nikki on tonight. It runs but has a high idle 1500 or so. Other than
that it seems to work pretty well. I will have to test drive it tomorrow.

The high idle may be due to the primary fuel jets being drilled out but I
didn't touch the primary air jets on top. That may make it overly rich at
idle. The idle fuel adjust seemed to have very little affect. When I looked
down the primaries during idle I can see fuel dripping fairly constantly in
both barrels but it doesn't look very well atomized. Could be just the low
air flow or is it a symptom of not drilling those primary air jets to match.

I also need to hook up the FBVS as that may be causing me some headaches
as well.

I don't think I have any vacuum leaks. I put a vacuum guage on the second
nipple from the front of the carb base gasket and it read a steady 10 and when
I blipped the throttle shot up to 15 or 20 and steadily returned to 10 as it
settled back to idling (at 1500 rpm). I expect if I could get it to idle at 750 rpm
that initial vacuum signal would be zero since thats the one for the advance on
the dizzy ( to my understanding anyway).

Of course I want to take this down to the Mitty this weekend and my wife
thinks I'm crazy. Maybe I am but its fun

t_g_farrell · 04-26-2012, 09:23 PM

I hooked up the FBSV and drilled the primary air bleeds to match the fuel jets.
No big difference. Also realized I forgot to plug the banjo bolt hole on the intake
manifold. Can you say vacuum leak. Plugged it with a bolt. Still has a high idle.

Took it for a test drive and it pulls pretty well and smacks you when you hit
the secondaries big time. Those need adjusted to come on a bit earlier but
thats minor. Won't hold idle and easily floods. Pretty sure its a vacuum leak
probably around the throttle body and/or spacer.

Definitely not taking the car with this carb to the Mitty. I may just swap the
Dell back on and go with that and come back to this at some later date.

cshaw07 · 05-07-2012, 09:52 AM

Check for a vac leak where the primary throttle shaft slides into the throttle body on the linkage side of the carb. My sterling had a nasty leak there. There is a write up of mine stickied on 7club on how to fix that with an o-ring if you find a leak there.

I had the same problems with my carb when I got it. High idle, would stall when coming to a stop, under 1,800 RPM it would buck bad. Had to really know how to drive it to make it work right. I was at DGRR with the carb un-working lol For some reason too, my A/F screw has to be WAY WAY out but shes idling good now at about ~800RPM with 15in/vac at idle. Before it would do exactly what yours is doing, little to no vac under 1500RPM, but I used the third nipple from the left on the carb spacer.

t_g_farrell · 05-07-2012, 09:57 AM

Yeah I was going to check with some propane around the shafts. I remember
when I pulled the primary shaft out to cut it up it had some gooey stuff on the
shaft. I may try pushing some grease into it from both sides and see how that
works.

I won't get back to this until June, too much other stuff around the house to
deal with at the moment.

04-25-2012, 08:48 PM	#31
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 426 Rep Power: 0	I put the nikki on tonight. It runs but has a high idle 1500 or so. Other than that it seems to work pretty well. I will have to test drive it tomorrow. The high idle may be due to the primary fuel jets being drilled out but I didn't touch the primary air jets on top. That may make it overly rich at idle. The idle fuel adjust seemed to have very little affect. When I looked down the primaries during idle I can see fuel dripping fairly constantly in both barrels but it doesn't look very well atomized. Could be just the low air flow or is it a symptom of not drilling those primary air jets to match. I also need to hook up the FBVS as that may be causing me some headaches as well. I don't think I have any vacuum leaks. I put a vacuum guage on the second nipple from the front of the carb base gasket and it read a steady 10 and when I blipped the throttle shot up to 15 or 20 and steadily returned to 10 as it settled back to idling (at 1500 rpm). I expect if I could get it to idle at 750 rpm that initial vacuum signal would be zero since thats the one for the advance on the dizzy ( to my understanding anyway). Of course I want to take this down to the Mitty this weekend and my wife thinks I'm crazy. Maybe I am but its fun __________________ 1980 GS stockport, RB Dellorto carb/intake, Carter fuel pump, Holley regulator, RB Street port exhaust, TFIDFIS, MR2 MK I electric fans, 2G strut bar Project Fat Nikki Budget 12A rebuild Video setup < $30.00

04-26-2012, 09:23 PM	#32
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 426 Rep Power: 0	I hooked up the FBSV and drilled the primary air bleeds to match the fuel jets. No big difference. Also realized I forgot to plug the banjo bolt hole on the intake manifold. Can you say vacuum leak. Plugged it with a bolt. Still has a high idle. Took it for a test drive and it pulls pretty well and smacks you when you hit the secondaries big time. Those need adjusted to come on a bit earlier but thats minor. Won't hold idle and easily floods. Pretty sure its a vacuum leak probably around the throttle body and/or spacer. Definitely not taking the car with this carb to the Mitty. I may just swap the Dell back on and go with that and come back to this at some later date. __________________ 1980 GS stockport, RB Dellorto carb/intake, Carter fuel pump, Holley regulator, RB Street port exhaust, TFIDFIS, MR2 MK I electric fans, 2G strut bar Project Fat Nikki Budget 12A rebuild Video setup < $30.00

05-07-2012, 09:57 AM	#34
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 426 Rep Power: 0	Yeah I was going to check with some propane around the shafts. I remember when I pulled the primary shaft out to cut it up it had some gooey stuff on the shaft. I may try pushing some grease into it from both sides and see how that works. I won't get back to this until June, too much other stuff around the house to deal with at the moment. __________________ 1980 GS stockport, RB Dellorto carb/intake, Carter fuel pump, Holley regulator, RB Street port exhaust, TFIDFIS, MR2 MK I electric fans, 2G strut bar Project Fat Nikki Budget 12A rebuild Video setup < $30.00

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

05-07-2012, 09:52 AM	#33
cshaw07 The Newbie Join Date: May 2012 iTrader: (0) Posts: 12 Rep Power: 0	Check for a vac leak where the primary throttle shaft slides into the throttle body on the linkage side of the carb. My sterling had a nasty leak there. There is a write up of mine stickied on 7club on how to fix that with an o-ring if you find a leak there. I had the same problems with my carb when I got it. High idle, would stall when coming to a stop, under 1,800 RPM it would buck bad. Had to really know how to drive it to make it work right. I was at DGRR with the carb un-working lol For some reason too, my A/F screw has to be WAY WAY out but shes idling good now at about ~800RPM with 15in/vac at idle. Before it would do exactly what yours is doing, little to no vac under 1500RPM, but I used the third nipple from the left on the carb spacer.