Nibbi Racing PE30. - Page 3

Ariel Red Hunter · 06-22-2019, 01:05 PM

Quote:

Originally Posted by JerryHawk250

I couldn't agree with you more.

Makes all the difference in the world. When I was looking at the PE30 the price was right at $100. A little more than I wanted to spend at the time. The PWK30 works great too but if I had to do it all over again I would go with the PE30 because of the easier access to the idle speed and mixture screw. On mine with the shorter intake tube I can access them pretty easy but the PE30 is a way better option.

There is a signifigant top end powe boost from running a longer intake tube (manifold to the ignorant) rather than a short one, especially with an extractor type exhaust system. And no, putting a long "trumpet" on a close mounted carb does not work any where near as well. ..ARH

Megadan · 06-22-2019, 05:01 PM

Quote:

Originally Posted by Ariel Red Hunter

There is a signifigant top end powe boost from running a longer intake tube (manifold to the ignorant) rather than a short one, especially with an extractor type exhaust system. And no, putting a long "trumpet" on a close mounted carb does not work any where near as well. ..ARH

Without getting into intake harmonics and all of the math involved, this is actually accurate. Intake length isn't just a longer or shorter - torque vs. horsepower. You can have very long intake runners and still have immense top end HP. It's all about resonance wave tuning and matching a harmonic wave length to a specific RPM range so that the resonance wave returns to the node (valve) just before it opens to greatly increase cylinder filling at that desired RPM range. Cam profile dictates the length of the intake.

A trumpet can actually be used to tune the length to the anode, thus altering the resonance wave length. Having the carburetor further away does have an advantage in regards to fuel atomization thanks in part to an increased draw on the jets and giving it more time to mix with the air before it reaches the cylinder, as well as isolating the carb from the engine heat more, keeping the fuel cooler. The downside is, it also makes the engine far more sensitive to fueling changes, which is why dialing in the idle mixture is a little more of a challenge. Small changes in the screw position can create big changes in how the motor behaves. I was down to 1/8th turns and still struggling lol.

Ariel Red Hunter · 06-22-2019, 06:51 PM

Quote:

Originally Posted by Megadan

Without getting into intake harmonics and all of the math involved, this is actually accurate. Intake length isn't just a longer or shorter - torque vs. horsepower. You can have very long intake runners and still have immense top end HP. It's all about resonance wave tuning and matching a harmonic wave length to a specific RPM range so that the resonance wave returns to the node (valve) just before it opens to greatly increase cylinder filling at that desired RPM range. Cam profile dictates the length of the intake.

A trumpet can actually be used to tune the length to the anode, thus altering the resonance wave length. Having the carburetor further away does have an advantage in regards to fuel atomization thanks in part to an increased draw on the jets and giving it more time to mix with the air before it reaches the cylinder, as well as isolating the carb from the engine heat more, keeping the fuel cooler. The downside is, it also makes the engine far more sensitive to fueling changes, which is why dialing in the idle mixture is a little more of a challenge. Small changes in the screw position can create big changes in how the motor behaves. I was down to 1/8th turns and still struggling lol.

Yes, I learned the basics of intake tuning from P. Irving's book "Tuning for Speed".Then I experimented with it through the late '40's until by the late 50's it was pretty well established as "the next big thing", and it certainly was on flat track and road racing...ARH

Megadan · 06-24-2019, 04:12 PM

I have noticed a strange behavior with the slide. The spring for it is much lighter than the pz30 unit, so it doesn't like to fully close at random when under high vacuum. I am going to look into using the pz30 or pwk springs, or finding another option. This was causing me to think my bike was lean because the revs would stay at 2krpm for a bit. Blip the throttle and it would settle back down, which helped me figure that out. I could feel it even while coasting in gear, which the throttle blip also solved. I love quirky issues like this...

**JerryHawk250** · 06-24-2019, 04:28 PM

That's where I'm at right now too. I need a 122 main. 125 too rich and 120 is lean. Temps were in the mid 90's over the weekend with a heat index of around 105. The 125 was a little too much. Surprised my oil temps never got over 200 but head temps got up to 310 at one point where I had to maintain 70mph for a few miles on the interstate. Had a goodstrong tail wind going to a local one of the festival. Got her up to 75 with some throttle left but on the way back bucking the same wind 75 mph was about all she had. The wind really effects the speed with the taller gears.

Megadan · 06-24-2019, 07:42 PM

The 120 is lean on mine as well, but it is on the safe side of lean and pulls very strong. As long as the temps stay on the hot side, over 80, it should be just fine. I have a 122 on the way though. The trickier challenge is going to be the slide spring. I am thinking I might try the pwk spring inside the PE30 spring to see how it feels. If that is too stiff I may just try and stretch the PE spring a little bit.

**JerryHawk250** · 06-24-2019, 10:29 PM

Are you having any problems with the cable binding?

Megadan · 06-24-2019, 10:35 PM

Quote:

Originally Posted by JerryHawk250

Are you having any problems with the cable binding?

Nah, cable is fine. The spring on this carb is very light, almost half the rate of the pz30. Feels like almost no resistance at the throttle tube.

**JerryHawk250** · 06-25-2019, 07:38 AM

Quote:

Originally Posted by Megadan

Nah, cable is fine. The spring on this carb is very light, almost half the rate of the pz30. Feels like almost no resistance at the throttle tube.

Will the one off your PZ30 fit?

Megadan · 06-25-2019, 11:41 AM

Quote:

Originally Posted by JerryHawk250

Will the one off your PZ30 fit?

Nope, too short lol Just experimenting with ideas. I have some mikuni VM parts laying around, so I might see if a VM30/32 spring is similar in size. If not, like I said, I can always give the spring a bit of a stretch.

Wild Dog · 06-25-2019, 01:41 PM

Why not a spring from a genuine Kehin PE30???
http://www.keihincarbs.com/carbs/pe/gate.html

Megadan · 06-25-2019, 07:19 PM

Quote:

Originally Posted by Wild Dog

Why not a spring from a genuine Kehin PE30???
http://www.keihincarbs.com/carbs/pe/gate.html

Thats my last resort lol. I have boxes of carburetors and parts, so if I have something on hand that will work, why spend more money?

G2ic22 · 07-20-2019, 12:27 AM

So i finally got nibbi installed tonight and I can tell once I dial it in it's going to be one raped ape!!! Wants to bog out though from anywhere after about quarter throttle. Needle on notch 4 and have 38 pilot with 118 main. Seems really strong right off idle but soon bogs thereafter. Does ok when ease throttle but still no go. Think need to drop needle to 5 and go bigger main. Plug looked brown and dry so not rich I don't think. Plug could been that way from previous carb but didnt turn black from my short spin and to dark to see any black smoke but first thing in the AM I'm going to try dial it in didnt want to piss off the neighbors haha but she sure has a even meaner grunt with the nibbi sounds like a I remember a yz450 just plain mean and I absolutely gone ape shit!!!!

G2ic22 · 07-20-2019, 10:57 PM

Well the nibbi sure is a finicky carb to tune I'll say that. I had a few issues today spent most of the day on it. One thing the throttle spring as you stated Megadan is way to soft and had me chasing the wrong jets most the day. The slide as you said sticks open and didnt close all the time causing idle to be high when stuck from vacum not letting it seat. After switching spring from the vm26 which actually fit in the cup of the cap and perfectly to the black spring seat in the carb. After having the stiffer spring then I could finally make so leeway. The carb is extra sensitive as stated to even the slightest adjustments to the air screw and idle screw. So the weird thing is the power is inconsistent and what I mean is when take off from idle full throttle giving her all shes got through few gears it screams and gas great power but slow down and try again within a few second go bang through the fears again it doesnt have same power it comes out flat. It's like it takes all the fuel the first go around and half to slow down and putt for a second then hit it and it screams through gears but if you bang through the gears at WOT slow down and hit WOT again to quick it just doesnt have the same pull as the first time unless let off. It's almost like you half to wait for the fuel to load back up like it drains the carb and needs to fill back up to hit it again and get same power. I checked the float and even made it to get more before float closes the valve but same thing. It doesnt really bog out or miss it just needs like time to re fuel or recharge for a minute to get the same power response otherwise it's just wont pull hard if you continuously try to let her RIPP. Plug is good and brown with little black it's not Rich. I have 128 main anything lower makes it worse and the 130 Boggs out. Needle has to be on 1st notch anything after will make it cut out from quarter throttle. Its dialed in pritty good but csnt for the life of me see why it will pull real hard for one pull but dont let off the gas and try keep giving it hell it starts to lose power but let it load back up and take off it pulls really hard.

Megadan · 07-20-2019, 11:48 PM

I would wager a guess that you are still too rich on the pilot circuit. I could never get a 38 to idle correctly and it still had issues with fuel surging and pooling at idle, which would then cause a bog once it transitioned to the needle jet. Your scenario with the blast through gears, let off, then blast again sounds to me like the vacuum draw when you let off the throttle combined with the very rich pilot jet is causing a buildup of fuel in the intake that then becomes a big rich wave of fuel when you try to open the throttle again. This would also explain why your needle is maxed out in the leanest position. I have been able to run the needle in the 4th notch even on 122 main jet, but it starts to get a bit too rich on a 125 or larger.

Setup is a 35 pilot, 135 main, 1 7/8 turns out on the mixture screw. needle in center slot.

06-24-2019, 04:12 PM	#34
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,011	I have noticed a strange behavior with the slide. The spring for it is much lighter than the pz30 unit, so it doesn't like to fully close at random when under high vacuum. I am going to look into using the pz30 or pwk springs, or finding another option. This was causing me to think my bike was lean because the revs would stay at 2krpm for a bit. Blip the throttle and it would settle back down, which helped me figure that out. I could feel it even while coasting in gear, which the throttle blip also solved. I love quirky issues like this... __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124 Last edited by Megadan; 05-07-2020 at 05:07 AM.
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06-24-2019, 04:28 PM	#35
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,557	That's where I'm at right now too. I need a 122 main. 125 too rich and 120 is lean. Temps were in the mid 90's over the weekend with a heat index of around 105. The 125 was a little too much. Surprised my oil temps never got over 200 but head temps got up to 310 at one point where I had to maintain 70mph for a few miles on the interstate. Had a goodstrong tail wind going to a local one of the festival. Got her up to 75 with some throttle left but on the way back bucking the same wind 75 mph was about all she had. The wind really effects the speed with the taller gears. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel Last edited by JerryHawk250; 06-24-2019 at 05:05 PM.
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06-24-2019, 07:42 PM	#36
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,011	The 120 is lean on mine as well, but it is on the safe side of lean and pulls very strong. As long as the temps stay on the hot side, over 80, it should be just fine. I have a 122 on the way though. The trickier challenge is going to be the slide spring. I am thinking I might try the pwk spring inside the PE30 spring to see how it feels. If that is too stiff I may just try and stretch the PE spring a little bit. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

06-24-2019, 10:29 PM	#37
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,557	Are you having any problems with the cable binding? __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
	0

07-20-2019, 12:27 AM	#43
G2ic22 Join Date: Jun 2019 Posts: 35	So i finally got nibbi installed tonight and I can tell once I dial it in it's going to be one raped ape!!! Wants to bog out though from anywhere after about quarter throttle. Needle on notch 4 and have 38 pilot with 118 main. Seems really strong right off idle but soon bogs thereafter. Does ok when ease throttle but still no go. Think need to drop needle to 5 and go bigger main. Plug looked brown and dry so not rich I don't think. Plug could been that way from previous carb but didnt turn black from my short spin and to dark to see any black smoke but first thing in the AM I'm going to try dial it in didnt want to piss off the neighbors haha but she sure has a even meaner grunt with the nibbi sounds like a I remember a yz450 just plain mean and I absolutely gone ape shit!!!! __________________ "If there's no modifications it's not fast enough!!!! Hawk250RedRyder2018 FlyRacing/D.I.D./ProTaper/JTSprockets/Nibbi30/DPR9EIX/PNP/KendaWashougal2/Acerbis/AlpinestarsTech5/HJC/.........TheRideContinues........RockyMountainHigh ..........LIFE ELEVATED!!!!
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06-25-2019, 01:41 PM	#41
Wild Dog Join Date: Dec 2016 Location: Argentina Posts: 756	Why not a spring from a genuine Kehin PE30??? http://www.keihincarbs.com/carbs/pe/gate.html
	0

07-20-2019, 10:57 PM	#44
G2ic22 Join Date: Jun 2019 Posts: 35	Well the nibbi sure is a finicky carb to tune I'll say that. I had a few issues today spent most of the day on it. One thing the throttle spring as you stated Megadan is way to soft and had me chasing the wrong jets most the day. The slide as you said sticks open and didnt close all the time causing idle to be high when stuck from vacum not letting it seat. After switching spring from the vm26 which actually fit in the cup of the cap and perfectly to the black spring seat in the carb. After having the stiffer spring then I could finally make so leeway. The carb is extra sensitive as stated to even the slightest adjustments to the air screw and idle screw. So the weird thing is the power is inconsistent and what I mean is when take off from idle full throttle giving her all shes got through few gears it screams and gas great power but slow down and try again within a few second go bang through the fears again it doesnt have same power it comes out flat. It's like it takes all the fuel the first go around and half to slow down and putt for a second then hit it and it screams through gears but if you bang through the gears at WOT slow down and hit WOT again to quick it just doesnt have the same pull as the first time unless let off. It's almost like you half to wait for the fuel to load back up like it drains the carb and needs to fill back up to hit it again and get same power. I checked the float and even made it to get more before float closes the valve but same thing. It doesnt really bog out or miss it just needs like time to re fuel or recharge for a minute to get the same power response otherwise it's just wont pull hard if you continuously try to let her RIPP. Plug is good and brown with little black it's not Rich. I have 128 main anything lower makes it worse and the 130 Boggs out. Needle has to be on 1st notch anything after will make it cut out from quarter throttle. Its dialed in pritty good but csnt for the life of me see why it will pull real hard for one pull but dont let off the gas and try keep giving it hell it starts to lose power but let it load back up and take off it pulls really hard. __________________ "If there's no modifications it's not fast enough!!!! Hawk250RedRyder2018 FlyRacing/D.I.D./ProTaper/JTSprockets/Nibbi30/DPR9EIX/PNP/KendaWashougal2/Acerbis/AlpinestarsTech5/HJC/.........TheRideContinues........RockyMountainHigh ..........LIFE ELEVATED!!!!
	0

07-20-2019, 11:48 PM	#45
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,011	I would wager a guess that you are still too rich on the pilot circuit. I could never get a 38 to idle correctly and it still had issues with fuel surging and pooling at idle, which would then cause a bog once it transitioned to the needle jet. Your scenario with the blast through gears, let off, then blast again sounds to me like the vacuum draw when you let off the throttle combined with the very rich pilot jet is causing a buildup of fuel in the intake that then becomes a big rich wave of fuel when you try to open the throttle again. This would also explain why your needle is maxed out in the leanest position. I have been able to run the needle in the 4th notch even on 122 main jet, but it starts to get a bit too rich on a 125 or larger. Setup is a 35 pilot, 135 main, 1 7/8 turns out on the mixture screw. needle in center slot. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124 Last edited by Megadan; 05-07-2020 at 05:03 AM.
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