Too rich?
 

Hey all just got my new carb on my magician and trying to get it dialed in. I noticed today when i went to start it today hadnt riden in a couple days used the choke got it started and i noticed my choke does absolutely nothing. When its idling i play with the choke and on full there is 0 change in rpms. If its cold i might have to use a spray of starting fluid to get it started then it idles fine and full choke has no effect the only info i could find on this said its possibly so rich that its not effecting but it should start fine..which it has trouble doing when its cold. Is this too rich of carb a bad thing? It runs and idles fine so playing with setting seems ??? But i want it to start righ up without having to carry around a can of spray. Advice? Would upgrading the electrics/battery/starter do anything for this?

General rule of thumb when it comes to the choke. At around 50 degrees or less it should be necessary to use full choke to start the bike, and how long full choke is needed just depends on how cold it is. Usually above freezing you should be able to switch down to half choke within 30 seconds to a minute at most. The colder it is, the longer it might take obviously. Above 50 to say 70 degrees, the bike should start with little to no choke. Even if full choke is needed to start, it should/will bog out very quickly if not changed to half choke. Even then, half choke is only needed for a minute or so and then it should maintain an idle with the choke off. Above 70, the choke really shouldn't be needed.

Too lean on the idle mixture will require more choke and for longer and make for harder starts when it's cold.

Too rich on the idle mixture will require less choke or no choke at all when cold, but in warmer temps the bike will be harder to start and require opening the throttle some for more air to get it to fire off.

No matter what the settings are, one thing to keep in mind is that until the engine gets warmed up, the idle will stay a bit on the low side due to the engine being cold. These don't have a bypass circuit or any sort of idle control, so it either requires nursing the throttle a bit to keep the revs up, or adjusting the curb idle speed with the knob on the side of the carb, and then re-adjusting once it gets up to temp.

Good info but let me rephrase i understand how a choke works so when my bikes idling and I play with the choke it has absolutely no effect and what I've read says that when this happens it's because it is so rich restricting airflow doesn't do much. Show the bike runs fine and idles fine after it starts up and the choke having no effect means something's not working right correct? And since the idle seems to be in about the right spot is it my air mixture that is off then do I have to play with the air screw? And lastly I was just thinking about it and how much does upgrading electrical and battery starter affect cold starts?

Ive got my after market carb on just trying to get it zeroed in like a laser!
On these bikes does it not matter, that is, if you havent ridin for a few days your going to have to nurse the throttle on startups till warm no matter what?

If it runs too rich alot it will wear out the rings and cylinder. Gas washes the oil off. That's why efi engines outlast carburated( no choke)

To answer your last question, monkeying with the electricals on your bike will have no effect on this whatsoever.


What kind of carb do you have? Some carbs use a true choke, i.e. a plate that rotates and physically blocks off some of the airflow going through the carb. Others, like the various Nibbi carbs (and "real" brand name carbs on many bikes, particularly Keihins) have a "choke" that is actually an enricher. Airflow is not changed when one of these is employed; rather, it opens a little port that allows more fuel into the mixture instead.


If your carb is one of the latter, and the enricher passages are gummed up or plugged, or you have some other mechanical issue with that system then it is perfectly possible that your "choke" is literally doing nothing. We'll need more info to make an accurate guess, though.

The use of quick start to get it running tells me your valves might be on the tight side ,and I don’t see a valve adjustment mentioned in any of your posts .The valves will disturb your tune and have you chasing your tail on carb things when in reality the carb is fine .

Interesting on the valves i have yet to do that. Bought the feeler gauges just was waiting...wanted to port the heads while i was down there but u dont need to tear up to do valves!

I have a genuine keihin pz30 and i am 99.9% sure it does not have an enricher. (I would have noticed it rejetting it right?)
Running a 110 main 42 jet (pz pilots are on a different sized scale for some reason) at 300ft. How do u upload picture that arnt teeny tiny?
Do any of you think i could be grabbing too much air, did an airbox delete with a 55mm diameter filter? Screw it id like to understand things better but i kept all my stock parts just incase. Guess u have to spend hours on end tinkering till its right

Definitely, adjust the valves. That's the number one problem when hard to start.

The PZ30 should have a traditional choke, yes. You can tell if you pop it off and look at it. The choke plate is easily visible in the inlet throat and is operated via the lever on the side. Enricher carbs typically have a plunger you pull instead.


I would ensure that your valves are in spec as Bruces has suggested before chasing your tail on other potential causes. These bikes typically leave the factory with the valve clearances way too tight (i.e. with none) which will cause your engine to run lousy and be hard to start. You can pick up a suitable feeler gauge set at Harbor Freight if you don't feel like waiting for one to show up in the mail.


Make sure your engine is 100% cold before checking and adjusting the valve clearances. Let it sit overnight, for instance.


FWIW, the traditional butterfly plate choke on my Bashan Enforcer does not change the bike's idle, either. That is usually an effect of enricher type carbs. What it does do, however, is make the engine misfire and stumble if the choke is closed and the engine is already hot.


If you want to post a picture on here that's bigger than a postage stamp I recommend uploading it to imgur or similar and just copy-pasting a link to it. That's what I do.

Picture posting methods

http://www.chinariders.net/showthrea...518#post369518

http://www.chinariders.net/showthread.php?t=14422

Postimage also works good and has the best picture quality

Thanks everyone good stuff. Ya even if mines warm full choke does nothing! Maybe theres a leak somewhere...goodthing i have plenty of starter fluid... freaking EVERYTHING comes loose on this bike just about every 20 minutes lol

One thing i did note though that i forgot to mention cuz its hard to explain without sound effects but im hearing a sound like a vaccum sound of something trying to pull or push (air or gas?) But then goes away and seems fine after a few seconds. Im guna work on it in a few hours ill post some pucs later.

This is my exact carb...actual pics otw

I don’t think that’s a genuine keihin carb looking at the pictures ,it looks like the $20.00 clones everybody is running and happy with .I don’t even see where it says keihin on it

I thot so too but its stamped on top. No enricher right? Normal pz30 with a standard choke right? Will link better pics soon

Yes ,normal pz carb with choke ,and no ,not original not even close .Many of the clones mark them ,first time I ever saw one marked in that area real or clone .Keihin is proud of their carbs and mark them (they cast their name on it ) on the body where the slide is ,so everybody can see who built it ,yours is marked where nobody can see it ,possibly on purpose so they can’t be sued ? I am sure it will work just fine .

Haha man 😄 made in "usa" ( town in china called usa) lmao

Apparently it is a JFG racing 30mm cable choke PZ30.

I am sure the jets I got from AliExpress fit perfectly! Including the two piece pilot jets!

And OP... you need to jet that carb!

Wrong
 

Looks like u all were WRONG
Genuine keihin japan baby
And it is jetted..jus having a too rich problem but the idle seems to be in thw right spot. Still no one has answered...shiuld i mess with the air screw setting?0

All carbs are "jetted". Adjusting jets is re-jetting, I guess. But factory jets are rarely optimum.

You still need to adjust the jets.

What did you pay for this JFG (genuine Keihin) carb? Can you share the source so folks here can buy one?

The JFG RACING Cable Choke PZ30 you posted pics of is a $25 clone, NOT a Keihin carb. Yup, I see that carb clone on Amazon, and there is not a cast Keihin logo on it. ???

And yall were so confident :) yes i kno i got the jet kit too ill link tht too...thumper can u not see the newest pic? Keihin japan cast with logo on throttle slide and weird keihin ink stamp with cerial # above filter end. Well thats what i ordered and a genuine keihin is what i got
24.99$ genuine pz30Check this out at Amazon.com
JFG RACING Cable Choke PZ30... https://www.amazon.com/dp/B073SVJF2Q...p_mob_ap_share
Pilot jet kit 10.99
Check this out at Amazon.com
Carbhub 10 pcs Carburetor Main... https://www.amazon.com/dp/B07F9MJGJX...p_mob_ap_share
It
https://www.amazon.com/dp/B085WTQDZ9...ing=UTF8&psc=1. Might want tht too adjusting on bike is not possible else wise
Couldnt find a main it comes with a 104 main and 40 jet had to drill my main out

Well yes. I saw the Keihin cast logo...Amazing. Lucky, I guess. The photos on the amazon listing do NOT show the casting on the slide tower/stack. :hmm: $25???

Maybe Japanese company Keihin licensed it.

Sorry you had to drill out the main. lots of replacement jets available and not expensive.

What will you do with the OEM carb?

Ya luck of the irish i guess. Theres the link tho buy em up haha. I was saving it in case i completely failed and couldnt get the new carb to work why need it?
Btw i have an extra 17 tooth front sprocket ordered wrong spline size. Size is 17mm i think? Anyone want it up gor grabz?

My current PZ30B says Made in Japan, and it was bought directly from China.

My Mikuni VM26 said "Mikuni Japan" also from China.

Fact: They can make it say anything they want to, doesn't mean it's true.

Second Fact: A real PZ27 framed carburetor has a gusset between the slide tower and rear flange. The "PZ30" sold on the internet is a copy of the 27 with an enlarged throat, but it is missing said gusset. Picture: https://www.jetsrus.com/photos/photo_JRU-0315.jpg

Final Fact: Keihin never made a 30mm PZ carburetor. The largest official Keihin PZ production carb was the PZ27. The PZ30 is a modified clone made under license by a couple of chinese companies for their clone bikes, and a few others without a license because they can.

Real Keihin PZ carbs use 99101-116 main jets and N424-74C slow jets. Clones don't use either of those. Often using the 393 main jet instead of the 116, and the 21 variant of the slow jet

I dunno about that where did u read that the internet? It looks legit main looked up the cerial also to clarify the seller most likely doesnt know what they have happens A Lot on amazon stores most likely matching the other prices for similar items (clones) the ad didnt even mention it was keihin and didnt even include a pic of the cast stamp most likely to avoid repercussions of selling things unliscenced so why would thy go thru all that work then not advertise it? I think its more likely they started making them for the clone craze but thats not here or there tho cuz ....still noone answering question about playing with the air screw....? Ive rebuikt a few carbs but never had to mess with the air screw from factory settings? When should u play with the air mixture? Moreover could i lean it out by backing the air screw out more?

I don't need the internet to know this stuff, I've been working with carbs and bikes for many many many years.

But, if you really need to know this stuff, use the internet and read something. Here is a great example... Keihin doesn't produce PZ carburetors anymore, and haven't for years. That's why I know the one you found isn't real. Let alone the previous fact I mentioned, that the PZ27 was the largest version they produced when they did make it.

Unfortunately, the carb you have listed isn't a real one. If you believe me or not is up to you as I have nothing invested in this personally. I only wish to stop misinformation and present the facts as they are. This doesn't mean the carb you have is a bad one. Hell, I run a PZ30B on my Hawk and it runs great. :shrug:



As far as adjusting the "air screw", that would be impossible. The idle mixture screw on the PZ carburetors is a fuel screw - aka it controls the fuel fed from the bypass of the pilot jet circuit to the small port behind the throttle slide. Air screws are located before the slide and directly block airflow through the idle air bypass port at the carb entrance.

When should you adjust it? When you encounter idle issue or hard start issues in certain scenarios. Hard starts while hot due to being too rich, or hard starts when cold from being too lean. Needing the choke to start during warm weather, or not needing the choke at all in cold weather. A hanging high idle after letting off the throttle, or a boggy unsteady low idle. etc. etc.

Again, there is plenty of information out there on the internet that you can read.

JerryHawk set me straight on the fact that it is a fuel screw. Knowing that makes a huge difference for tuning:)

Mega, your comments on the consequences of too lean, or too rich on the pilot circuit are very useful, and make sense. I changed from a 34 to a 38, and was able to close the pilot screw to ~2.5 turns (it was out at 4+ turns). It has a nice stable idle, but I will pay more attention to cold start and hot start now.

It does drop to a nice idle throttle off, and never needs choke when warm. Those bracket the too lean, too rich conditions. But it never starts for me with the kick start. Fortunately, it pops to life quick with the starter every time. I will try half choke (mine is manual, two position choke) when hot and kick start it. If it is easier to start on half choke by kick starter when hot, I will move to a bigger jet. But it starts easily when cold if I have if fully choked, and seems to get better at half choke or even no choke quickly (but with low idle initially-sometimes I lift the slide with the idle adjust until warm). It seems pretty close at least.

It is opened up on the exhaust side only, so the carb is experiencing lots of vacuum. I was wondering if that may be an issue? I do not know if there is an optimal vacuum range for the PZ :hmm:

Sigh..........
Im talking about what this diagram refers to as the moxong chamber screw.....still a lil confused here forgive me i have brain damage for real..plz dumb it down a little for us simpletons. Last time ill try to relay this promise... after putting on aftermarket carb with 104 main tapped put to 110 with a 42 pilot. Funny how only one person told me to check my plugs when thats the correct way to sus this out (after doing some research) and ill do that lateer but i dont think ive ran the new carb long enough with the suspected too rich settings so how long will it take to show up balck and sooty if its too rich? Also having problems with cold starts (the bike being not warmed up but still in warm weather) but idle after warmed is strong and around right rpms with no bog or throttle hang or w.e. its called. Like i said before 8 know how to play with idle but jever had to adjust the "chamber mixture screw" from stock settings. Should i mess with that or should i try to lean out the carb with smaller pilot or main that is if it does end up being too rich? This is my only mode of transportation rn as my trucks transmission just went out and dont have the mula to fix tht situation and carrying around a can of started fluid doesnt sound fun

Magician

Gently tighten the pilot adjust screw all the way ("mixing chamber"), then open it 2 and a half turns. Then follow instructions in post #25, above. 2 and a half is within a half turn of ideal place to be if the pilot jet is correct. This is where you want to be when ypou are eventually jet properly.

Whenever you ask for advice, list details, symptoms. Any more is just a distraction
These details are important: any exhaust mods or replacement, any airbox/intake mods or delete.

For pilot circuit, Mega's instruction in post 25.

Thanks thumper! That makes sense now. Found a website that is the best ive found on everything u need to know about carb tuning if it helps anybody else:
https://janetpanic.com/how-do-you-ad...torcycle-carb/

I know now on my carb has fuel "mixture" screw not an airscrew even tho those terms are used interchangeably a lot even tho its wrong creating confusion. Think of it as idle sets idle speed and mixture is amount of fuel (i think) so even tho my idle speed is correct the mixture is off which is why its having a hard time starting and most likely too rich which is why choke has no effect on rpms (making it richer does nothing when already too rich.) Most likely have toadjust the mixture because i did an airbox delete so its pulling way more air than it had on stock setting.(just a theory) either way after a few more rides i will check the plug color to determine too rich or too lean or perfect. Sorry it took a while for my damaged brain to understand :]

P.s. :
I just read a comment review on the carb i bought and i
He speaks on this carb having an extra 10mm float height than the pz30 manual says it should be leaning it out.....
""I got this for my 07 Rocketa DB-07 which is a lot like a Hawk 250 except it is a 200cc motor, it came with a Walbro PZ30 and is identical to this one. Do not run this without checking it first. Mine came with unmarked jets so I had no clue what was installed. The float was way off as well it should be 14mm on float height according to the factory Keihin PZ30 manual, mine was at 24mm which is super lean. This is measured with the carb upside down, float tab resting on the fuel shut off needle and measuring from the carb body where the float bowl seal sits to the top of the float. It should look level from the "top" of the float when it is correct. The standard Jets on a Keihin are 96 Main and 38 Pilot. The fuel/ air mix screw was only 1 turn out as well, you should start at 2 turns out for a good start. I know most of us that have knowledge of carbs already know you need to check these things out before installing on your bike and jetting will almost always be needed as we all live or ride in different elevations or climate. Other than the "issues" mentioned it seems to be a very well made carb and the finished product is very nice and the machining and casting was well done. Also don't forget to check your needle valve you should also start out with it on the 3rd step down from the top which put's it in the middle for a good starting point. This jet kit here on Amazon works with this carb. I got it for my original PZ30 and the jets are an exact match, as they are for this one.""
Does anybody know how important this aspect of a carb or any exp. With tht issue u could speak on? Considering im getting good fuel flow should i even give this a second thought?