ideal throttle response?? wot from idle?

#21
Adding this- I wonder if valve cover pressure is pushing fuel past the needle/seat? Or pressurizing the float bowl?
Yes, that is exactly what is happening to the float bowl. Did you have similar issues with this, and the square fuel pump? The rounder ones that I am running seem to be more popular, but hell the square ones probably work just as good.

The T-line ran from line out of the fuel pump to the carb back to the gas tank helps reduce unnecessary fuel flooding into the 24mm flatslide float bowl, and directs extra gas back into the gas tank. The flow back into the tank is pretty good, and also helps with venting.

Honestly at first it was dumping fuel pretty bad, but after some riding it seemed to get better-ish? The ride is 10x better with this fuel pump than without it, however it is causing a rich spot mid range which may need to raise the needle position 1 clip. Also need to play around with the a/f screw.

I have the sidecover pulse fitting into the catch can *crankcase pressure*, and the valve cover pulse fitting *valve pressure* feeding the pulse on the fuel pump.

Do you think putting the sidecover pulse fitting into the fuel pump pulse fitting (less pressure), and diverting the pulse fitting from the valve cover *excessive pressure*? to the catch can would help alleviate this issue?

One thing I do not have is an intake manifold pulse fitting so it would either be from the side cover or the valve cover fittings ideally... Think its a better idea to tap into the intake manifold, and have an NPT fitting off there?

Also these are my last runs. Jets. Max speed. Gear ratios. Hopefully it’ll help someone in the future.

24mm pwk mod 275 camshaft
.2” over rod
All billet rod, flywheel, m
Flattop piston 14.5-15” tires
1.3 billet roller rockers

1st test run 130 main/42 pilot/gold needle in 2rd position 5.0 gear ratio 12/60
Hit 60.8mph

2nd test run 135 main/35 pilot jet/regular needle in 2nd position 4.53 gear ratio
Hit 57.5mph

3rd test run 135 main/40 pilot/regular needle in 3rd position 4.53 gear ratio
Hit 59.2mph

4th test run 120 main/38 pilot/gold needle in 3rd position 4.54 ratio *added fuel pump*
Hit 59.4mph

5th test run 120 main/38 pilot/gold needle in 3rd position 4.916 ratio 12/59 *added fuel pump, but issues with richness on low end *aka flooding out carb* top end keeps chugging* and it was rainy/wet
hit 58.5mph she felt pretty good... need to figure out overflowing out of carb.... that definitely is messing up with the jetting...float level... everything....
 
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#22
I never had any issues with my setup. And that is a 33mm Mikuni and I have spun that motor over 9k RPM.
Also it runs on methanol so pushing a lot of fuel. No issues with fuel delivery at all.

I think the issue may be that you are trying to use pressure to operate the fuel pump, when you really should be using a vacuum signal. Moving the pulse fitting from the valve cover to the side cover will not change anything. It is the same crankcase pressure either way. It’s like your fuel pump is working backwards when you think about it.
High RPM = low vacuum, idle = high vacuum
High RPM = high pressure, idle = low pressure
Hope this explains it.

I would remove the intake manifold, drill and tap a hole and add a pulse fitting there. Then use vacuum to operate the fuel pump, and send both the valve cover/side cover to the catch can.
Or someone must sell an intake manifold with a pulse fitting already installed, might be easier.
 
#23
I never had any issues with my setup. And that is a 33mm Mikuni and I have spun that motor over 9k RPM.
Also it runs on methanol so pushing a lot of fuel. No issues with fuel delivery at all.

I think the issue may be that you are trying to use pressure to operate the fuel pump, when you really should be using a vacuum signal. Moving the pulse fitting from the valve cover to the side cover will not change anything. It is the same crankcase pressure either way. It’s like your fuel pump is working backwards when you think about it.
High RPM = low vacuum, idle = high vacuum
High RPM = high pressure, idle = low pressure
Hope this explains it.

I would remove the intake manifold, drill and tap a hole and add a pulse fitting there. Then use vacuum to operate the fuel pump, and send both the valve cover/side cover to the catch can.
Or someone must sell an intake manifold with a pulse fitting already installed, might be easier.
Amazing post. I'll report back with results in about 2-3 days.
 
#24
Amazing post. I'll report back with results in about 2-3 days.
1st test run 130 main/42 pilot/gold needle in 2rd position 5.0 gear ratio 12/60
Hit 60.8mph

2nd test run 135 main/35 pilot jet/regular needle in 2nd position 4.53 gear ratio
Hit 57.5mph

3rd test run 135 main/40 pilot/regular needle in 3rd position 4.53 gear ratio
Hit 59.2mph

4th test run 120 main/38 pilot/gold needle in 3rd position 4.54 ratio *added fuel pump*
Hit 59.4mph

5th test run 120 main/38 pilot/gold needle in 3rd position 4.916 ratio 12/59 *added fuel pump, but issues with richness on low end *aka flooding out carb* top end keeps chugging* and it was rainy/wet
hit 58.5mph she felt pretty good... need to figure out overflowing out of carb.... that definitely is messing up with the jetting...float level... everything....

6th test run 125 main/38 pilot/gold needle in 3rd position 4.53 ratio *ran without fuel pump*
hit 57.5 mph
seem to be gear bound at 4.53 ratio and my fat arse at 230 lbs stuck at 57.5-59.5 mph range at only 6200 rpm... going to try out some different gear ratios... seems like 5.0-5.3 would be good for my weight, and top speed goal of 60mph while being peppy.

Got a new cylinder head, intake manifold, gasket, and hose. Buttoned her up, and got rid of any air intake/leak issues. Can't believe my first run was the best run so far lol. The jetting was way off on the first run (rich), but the gear ratio was way closer to where I need to be.

Going to try a 5.0 ratio with new improved jetting, and see if i can beat my 1st test run of 60.8 mph. Currently I am running no fuel pump, and will only add it in if needed. If I beat my 60.8mph record I will keep testing/tuning to get it optimized.
 
#25
Update: What really helped my idle to wot response was increasing my pilot from the stock pilot size of 38 to 42. I snap the throttle at idle to WOT, and now the response is crispy.

I'm currently on my 8th test run lol... my previous record was 60.8mph, but I got my carb tuned in pretty close to perfect, and going to take her for a rip in a few hours.

Currently tuned the 24mm pwk flat slide with - 125 main/42 pilot/gold needle in 3rd position with 13/66 gear ratio 5.07 gear ratio.... *went richer on needle/leaner on main hoping to crack 60.8mph tonight*

on my personal record run I hit 60.8mph with 130 main/42 pilot/gold needle in 2rd position 5.0 gear ratio 12/60
Hit 60.8mph
 
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