Nibbi PE28FL - Page 3

toneloc6530 · 03-23-2022, 10:02 AM

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The carb comes with really good tuning instructions. This should be a sticky

toneloc6530 · 03-23-2022, 12:58 PM

I always thought screwing the mixture screw in made it leaner though

Dusman · 03-23-2022, 01:55 PM

On a carb that has a fuel screw yes, but this is an air screw. In most carbs, if the screw is in the front of the carb and underneath, it will be a fuel screw. If it is at the back of the carb near the carb intake, it will be an air screw (i.e., it controls the amount of air allowed into the mixture, at least in a "fine-tuning" sense).

Megadan · 03-23-2022, 03:30 PM

Quote:

Originally Posted by toneloc6530

I always thought screwing the mixture screw in made it leaner though

Dusman nailed it.

If the idle mixture screw is located before the bowl (inlet side of carb) like the PE carb then it controls how much air goes into the idle circuit. It quite literally just moves a rod that blocks a hole to meter air through a passage.

If the idle mixture screw is after the bowl like the PZ carb (outlet side) then it controls how much fuel is pulled through the circuit from the bowl. in essence it's a lot like the needle on the throttle slide, allowing more or less fuel through the passage based on how much the tip of the screw tip blocks the hole.

You probably wouldn't be too surprised to learn that a lot of people get this wrong when they switch to the PE carbs.

Megadan · 03-23-2022, 04:00 PM

I got my throttle cable in today. Of course the high temp today is 38 degrees, so no tinkering for me today, or likely the rest of this week.

Since I have a quick turn throttle most of the standard cables you would use on these bikes are actually too short/housing too long. I noticed Nibbi had a throttle cable listed and the cable size seems to be just about right. It also has an adjuster in the middle of the sleeve like a proper cable should.

For the price I am impressed. Hopefully it holds up over time, which is usually the real test. My only complaint is that they don't have just a black cable, so I decided to stick with the unintentional theme of my bike and ordered red.
https://www.amazon.com/dp/B07R9RZR5Z...roduct_details

Looks orange in their picture, but it is indeed red.

I also decided that I had to keep the cables matching, so I went ahead and ordered the red clutch cable too. I can keep my original as a backup. https://www.amazon.com/dp/B07R8PP1T6...roduct_details

This cable also has an adjustment in the middle of the housing. That gives 3 adjustments on the clutch cable in total. A tad overkill, but hey, good to have options.

toneloc6530 · 03-23-2022, 04:44 PM

Mine will bog if I crack the throttle really quick. If I roll on the throttle it is good. I don’t have enough experience to know if that would be a lean or rich condition with the needle position? Playing with air screw doesn’t seem to make a lot of difference. It doesn’t bog at WOT so I assume that might be normal or maybe needle adjustment.

Megadan · 03-23-2022, 09:18 PM

Quote:

Originally Posted by toneloc6530

Mine will bog if I crack the throttle really quick. If I roll on the throttle it is good. I don’t have enough experience to know if that would be a lean or rich condition with the needle position? Playing with air screw doesn’t seem to make a lot of difference. It doesn’t bog at WOT so I assume that might be normal or maybe needle adjustment.

Very possible you are too rich on the transition from one jet to the needle. Mine came with the needle in the 4th notch. I always start off in the 3rd/middle position. On my PE30 I had similar issues, a slight stutter when rolling on quickly. I moved my needle clip to the 2nd position (from the top) to lean it out some and it was perfect after that.

toneloc6530 · 03-23-2022, 09:33 PM

Thanks

Megadan · 03-30-2022, 12:15 AM

Got around to installing my PE28FL today. The nibbi throttle cable is actually too long. Not even a little too long, like every adjuster backed out of the threads and it still had a lot of slop too long. I am not exactly sure what the heck this cable is for, but I can't think of a single carburetor that could use it. I may actually buy a barrel, cut it, and shorten it to a useful length. It's a nice cable otherwise. Thankfully I did have a single pull cable from another throttle I bought that I forgot about and it worked out ok.

The clutch cable is too short for the stock Hawk holder to reach the lever arm. I am waiting for a CRF230F unit that bolts to the case further back to give that a try and see if it works. Necessary? No. Just another one of my tinkering experiments.

The carb installation itself - still having an issue with tank clearance and the throttle cable right at the top of the carburetor. I guess the nibbi is just tall and forward enough to hit in almost exactly the same place. At this point I am thinking I may just dent the damn fuel tank and be done with it.

It's not bad enough I couldn't get it mounted though, at least no worse than the PE30, and at least with the stock style intake there is a lot less intake flex/movement when riding.

Jetting I started with was essentially the jets right out of my PZ30B carb. The pilot is a 38, the Main is a size up at a 135 just to be safe. Idle mixture started at 2 turns out and I had to use the cold start enrichment to get it going. Once it idled for a few minutes I turned it in until I was 1 turn out and it started to stumble a bit. Backed off 1/2 a turn and it was much more stable, backed off another 1/4 turn and the idle holds dead steady at 1500. Hot restarts fire right back up. 2 turns out is just a wee bit lean on the idle, but still allows it to fall back to idle rpm without hanging up. I tend to like my idle a hair on the rich side with my compression being so high and my ignition advanced, so i am quite happy where it is.

I didn't get to check the main jet yet, but I suspect it will be fairly close. I did notice I get the same stumble transitioning to the needle like I used to get with the PE30 when I had it in the 3rd slot. I am going to simply move it to the second just like I did with that carb and be done with it.

China Rider 27 · 03-30-2022, 02:03 PM

You have probably already considered it in your analysis but sometimes those 90 degree cable carburetor inlets can help and they use more cable too.

Megadan · 03-30-2022, 04:53 PM

Quote:

Originally Posted by China Rider 27

You have probably already considered it in your analysis but sometimes those 90 degree cable carburetor inlets can help and they use more cable too.

I did actually consider that as well. I am just not sure if any I have seen would also clear the tank. I think no matter what I do I am going to have to ding my tank on the under side for clearance.

XLsior · 03-30-2022, 05:33 PM

how much of a clearance issue is it?
what about a degree of angle sanded off the manifold mating face...or the heat separator flange plate made into a slight wedge?

Megadan · 03-30-2022, 05:36 PM

Quote:

Originally Posted by XLsior

how much of a clearance issue is it?
what about a degree of angle sanded off the manifold mating face...or the heat separator flange plate made into a slight wedge?

It's enough to put pressure against the cable housing and press it tightly into the tank. 10mm or so of clearance would resolve the issue. I have no qualms with massaging the tank a bit to buy some space. My only other potential option might be an intake with less of an angle to the outside of the bike. That would put the top of the carb closer to the center of the frame, where the tank is out of the way.

China Rider 27 · 03-30-2022, 06:03 PM

Other PE30 I have worked with they use a molded cable end fitting stop instead of the screw in style. Some of the 90 degree cable ends are just a tube that sits in this slot and the cable fits flush at the end and only the cable itself goes in the tube. Could those be cut down. The Magician has this problem and I had to work through it some. On the Magician I used a 45 degree sloped back toward the center tank channel which gains some space. But dent in the tank no big deal either.

XLsior · 03-30-2022, 06:38 PM

Well there are some variations in the standard intake manifolds...finding the right 1 might be a faff though.

also the smaller intakes for 27/26mm carbs can be ported open...

But indexing the benefits of a metal fuel tank has its merits.

03-23-2022, 10:02 AM	#31
toneloc6530 Join Date: Apr 2015 Posts: 36	[IMG][/IMG] The carb comes with really good tuning instructions. This should be a sticky
	0

03-23-2022, 04:00 PM	#35
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,011	I got my throttle cable in today. Of course the high temp today is 38 degrees, so no tinkering for me today, or likely the rest of this week. Since I have a quick turn throttle most of the standard cables you would use on these bikes are actually too short/housing too long. I noticed Nibbi had a throttle cable listed and the cable size seems to be just about right. It also has an adjuster in the middle of the sleeve like a proper cable should. For the price I am impressed. Hopefully it holds up over time, which is usually the real test. My only complaint is that they don't have just a black cable, so I decided to stick with the unintentional theme of my bike and ordered red. https://www.amazon.com/dp/B07R9RZR5Z...roduct_details Looks orange in their picture, but it is indeed red. I also decided that I had to keep the cables matching, so I went ahead and ordered the red clutch cable too. I can keep my original as a backup. https://www.amazon.com/dp/B07R8PP1T6...roduct_details This cable also has an adjustment in the middle of the housing. That gives 3 adjustments on the clutch cable in total. A tad overkill, but hey, good to have options. __________________ 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

03-30-2022, 12:15 AM	#39
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,011	Got around to installing my PE28FL today. The nibbi throttle cable is actually too long. Not even a little too long, like every adjuster backed out of the threads and it still had a lot of slop too long. I am not exactly sure what the heck this cable is for, but I can't think of a single carburetor that could use it. I may actually buy a barrel, cut it, and shorten it to a useful length. It's a nice cable otherwise. Thankfully I did have a single pull cable from another throttle I bought that I forgot about and it worked out ok. The clutch cable is too short for the stock Hawk holder to reach the lever arm. I am waiting for a CRF230F unit that bolts to the case further back to give that a try and see if it works. Necessary? No. Just another one of my tinkering experiments. The carb installation itself - still having an issue with tank clearance and the throttle cable right at the top of the carburetor. I guess the nibbi is just tall and forward enough to hit in almost exactly the same place. At this point I am thinking I may just dent the damn fuel tank and be done with it. It's not bad enough I couldn't get it mounted though, at least no worse than the PE30, and at least with the stock style intake there is a lot less intake flex/movement when riding. Jetting I started with was essentially the jets right out of my PZ30B carb. The pilot is a 38, the Main is a size up at a 135 just to be safe. Idle mixture started at 2 turns out and I had to use the cold start enrichment to get it going. Once it idled for a few minutes I turned it in until I was 1 turn out and it started to stumble a bit. Backed off 1/2 a turn and it was much more stable, backed off another 1/4 turn and the idle holds dead steady at 1500. Hot restarts fire right back up. 2 turns out is just a wee bit lean on the idle, but still allows it to fall back to idle rpm without hanging up. I tend to like my idle a hair on the rich side with my compression being so high and my ignition advanced, so i am quite happy where it is. I didn't get to check the main jet yet, but I suspect it will be fairly close. I did notice I get the same stumble transitioning to the needle like I used to get with the PE30 when I had it in the 3rd slot. I am going to simply move it to the second just like I did with that carb and be done with it. __________________ 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
	2

03-23-2022, 12:58 PM	#32
toneloc6530 Join Date: Apr 2015 Posts: 36	I always thought screwing the mixture screw in made it leaner though
	1

03-23-2022, 01:55 PM	#33
Dusman Join Date: Jan 2018 Location: NC Posts: 212	On a carb that has a fuel screw yes, but this is an air screw. In most carbs, if the screw is in the front of the carb and underneath, it will be a fuel screw. If it is at the back of the carb near the carb intake, it will be an air screw (i.e., it controls the amount of air allowed into the mixture, at least in a "fine-tuning" sense).
	3

03-23-2022, 04:44 PM	#36
toneloc6530 Join Date: Apr 2015 Posts: 36	Mine will bog if I crack the throttle really quick. If I roll on the throttle it is good. I don’t have enough experience to know if that would be a lean or rich condition with the needle position? Playing with air screw doesn’t seem to make a lot of difference. It doesn’t bog at WOT so I assume that might be normal or maybe needle adjustment.
	0

03-23-2022, 09:33 PM	#38
toneloc6530 Join Date: Apr 2015 Posts: 36	Thanks
	0

03-30-2022, 02:03 PM	#40
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	You have probably already considered it in your analysis but sometimes those 90 degree cable carburetor inlets can help and they use more cable too.
	1

03-30-2022, 05:33 PM	#42
XLsior Join Date: Aug 2020 Location: Australia Posts: 1,286	how much of a clearance issue is it? what about a degree of angle sanded off the manifold mating face...or the heat separator flange plate made into a slight wedge?
	0

03-30-2022, 06:03 PM	#44
China Rider 27 Join Date: Dec 2018 Location: PNW Posts: 982	Other PE30 I have worked with they use a molded cable end fitting stop instead of the screw in style. Some of the 90 degree cable ends are just a tube that sits in this slot and the cable fits flush at the end and only the cable itself goes in the tube. Could those be cut down. The Magician has this problem and I had to work through it some. On the Magician I used a 45 degree sloped back toward the center tank channel which gains some space. But dent in the tank no big deal either.
	0

03-30-2022, 06:38 PM	#45
XLsior Join Date: Aug 2020 Location: Australia Posts: 1,286	Well there are some variations in the standard intake manifolds...finding the right 1 might be a faff though. also the smaller intakes for 27/26mm carbs can be ported open... But indexing the benefits of a metal fuel tank has its merits.
	0