Mikuni VM26 Carb from Amazon

[Megadan]

Originally Posted by Cravin01

The proof is in the pudding! Don't sweat the 40 jet, get some more cheap jets and go about your business.

My bike is now running a 115/40 combo up from a 110/33 and I didn't lower my elevation...get it? well I found that a fellow rider in my last Vlog got his pump carb in with a 112/39 setup and he hooked it up and it actually ran better than mine, I knew I was a little lean from checking my plug but the bike ran ok without getting too hot.

Now I'm trying to foul up my plug a little to find where too rich is, That's what I mean when I say get more jets and play around with it. I use to get a little pop or two letting off the throttle but I thought it was because I went to a open pipe, well now it's almost completely gone with the jet increase.


There are so many variables that's it's just best to see what work's for you and keep a open mind to any suggestion. Less restriction can take more gas & air, Higher elevation=less gas and air. not to mention not all carbs are created equal.your air box might just suck worse than mine...ok maybe not.

Take it for what it is but I can kick start or electric start on half choke without a twist of the throttle from COLD overnight start with a leaner 112/33 combo and and tad bit better running bike at 115/40.this may change as I see what happens and that's part of the fun here for me.

I swear by this pumper carb and the cold start pilot jets, The pumper should be the go to carb as opposed to the standard knock off mikuni replacement. I would like see how it compares to Jerry's power jet carb as I have no experience with it.

Just to clarify this so the jet numbers aren't too confusing. This is for a PZ30 Pumper carb. A #40 Keihin pilot jet orifice size is smaller than a Mikuni #40.

I haven't dialed my PZ30 Pumper in all the way yet, but in the cooler temps when I started my bike and ran it for a little bit, the 40 pilot worked flawlessly. I currently have a 120 main in, but I didn't get a chance to test it out before the snow fell, so no idea of how rich or lean it is with my ported head.

As far as the power jet carb, the comparison would be apples to oranges. Pumpers only add additional fuel during throttle roll on. A power jet adds fuel under high load with the throttle already open. It allows for leaner jetting at lower throttle positions to help make better power while helping to prevent going too lean at wide open. It works on 4 strokes to some extent, but it was originally designed for 2 smokes, which are much more sensitive to fueling having an effect on the power curve when they go a little rich at lower Revs.

[Cravin01]

yes I should have stated that, I'm taking baby steps also, please let me know how the 120 does. I haven't got any real time on the 115/40 yet to see how the plug looks but the bike responds nicely, If all is good I'll step up some more. I really appreciate all you contribute to the community Dan.

[Megadan]

Originally Posted by Cravin01

yes I should have stated that, I'm taking baby steps also, please let me know how the 120 does. I haven't got any real time on the 115/40 yet to see how the plug looks but the bike responds nicely, If all is good I'll step up some more. I really appreciate all you contribute to the community Dan.

The only thing that would make my main jet size not entirely applicable is the fact that I have a fairly aggressive port job on my head.

Just out of curiosity, where are you sitting with the needle adjustment? Part of the reason his may have run better than yours would be the needle position. Since the main jet really only comes into play in the last quarter turn of the throttle, the needle was likely playing a bigger role in why his setup seemed to run better. You could experiment by moving the clip up (leaner) or down (richer) and see how it changes.

Short of a wideband readout, the only way to judge the plug on the main jet is to do a wide open throttle plug chop on a decently long run. Once you have determined what the ideal main jet size is, then adjust the needle accordingly.

Just keep in mind that it is hard to fully compare two different setups. The best way to get your own carb dialed in is to find what main jet works best for your bike. I will personally favor a slightly rich WOT on an air cooled engine without fail.

[Cravin01]

I'm fairly sure it is at one position up, I have not needed to move it at all. now I want to go pull the slide to verify. His isn't running better at idle though, he has full range on the same exhaust setup without any pop or backfire so I raised mine more and it helped.

I expected to have it fall on it's face at full throttle and even be stubborn down low at idle with the jet increase on both main and pilot, The only difference I've found is it needs a bit of a warm up. I can't force it to wrap out without half choking at cold start like before while leaner. Once she is warm I have full range without the pops I suffered from earlier.

I know you have more aggressive flow with the ported intake and exhaust so I'm curious to see where you land. I truly wasn't expecting that big of a jet increase to work on my bike ..somehow it did.

[Ariel Red Hunter]

Originally Posted by Megadan

The only thing that would make my main jet size not entirely applicable is the fact that I have a fairly aggressive port job on my head.

Just out of curiosity, where are you sitting with the needle adjustment? Part of the reason his may have run better than yours would be the needle position. Since the main jet really only comes into play in the last quarter turn of the throttle, the needle was likely playing a bigger role in why his setup seemed to run better. You could experiment by moving the clip up (leaner) or down (richer) and see how it changes.

Short of a wideband readout, the only way to judge the plug on the main jet is to do a wide open throttle plug chop on a decently long run. Once you have determined what the ideal main jet size is, then adjust the needle accordingly.

Just keep in mind that it is hard to fully compare two different setups. The best way to get your own carb dialed in is to find what main jet works best for your bike. I will personally favor a slightly rich WOT on an air cooled engine without fail.

If one chose to install a cylinder head temperature gauge and sender, it can make setting up a lot easier. This link is to an explanation of how, and why. ......ARH

[NzBrakelathes]

Anyone thought or set up an EFI on these motors?
There are kits etc

[Megadan]

Originally Posted by NzBrakelathes

Anyone thought or set up an EFI on these motors?
There are kits etc

More than a few of us. The main reason none of us has taken that step really comes down to a couple of factors

There is one kit that is reasonably affordable that at least 4 or 5 of us have been genuinely interested in, but the track record for one member that used it was spotty, and the quality/reliability of the parts are unproven.

The one complete kit out there that has a decent track record (Ecotrons) is nearly half the price of the bikes it would be installed on.

We are a somewhat thrifty bunch, and a $25 carburetor and maybe another $20 in jets can provide a simple and reliable means of power. Plus, if enough time and effort is taken, the fuel economy is rather reasonable as well. I had my last Hawk dialed in well enough to hit a 75mph top speed with my linebacker sized butt in the seat all while being more than capable of averaging over 60mpg my with fairly heavy handed riding style.

[NzBrakelathes]

I have seen a few kit and yeah getting around $300 and tho EFI would be great I think it gets complicated real quick.
I am still thinking that there might be an easier way to sell a carb with jets from China but of course spending hours to make a kit happen that people don't like or want kinda gets to be pointless.
I will keep looking at what people want need tho n see if I can't put things together and sell to reduce the headaches - time will tell.

[The_DJ_Remixer]

Originally Posted by Megadan

Jet numbers for your pleasure.

Pilot Jet = VM28/486
Link - https://jetsrus.com/a_jets_by_carbur...-486_pilot.htm

Main Jet= N100.604
Link - https://jetsrus.com/a_jets_by_carbur...arge_round.htm

I highly recommend OEM jets, but if you want to keep it on the cheaper side of things then spring for the OEM equivalent. Don't waste your money on cheap jet kits from Amazon.

Size wise a 25, 27.5, or 30 for the pilot jet depending on mods and elevation. The 30 only seems to work well for guys at sea level though. At 1100ft I found the 25 to work well on a stock bike, and the 27.5 to work well with mods though it was a tad rich on hotter days. Ideally I should have drilled out a 25 pilot to a size between the two.

Main jet - 105/107.5 on a stock bike. 110 for just intake or exhaust, 115 for intake and exhaust are good starting points. Adjust as needed for temp and/or altitude.

Needle clip 1 down from center (4th from top) worked well for me, but depending on factors you may find 2 down works the best (bottom notch).

You stated vm28...but we were talking about the vm26 - 30mm carb. Is this the correct info for the knock off vm26? TY

[NzBrakelathes]

Originally Posted by The_DJ_Remixer

You stated vm28...but we were talking about the vm26 - 30mm carb. Is this the correct info for the knock off vm26? TY

https://www.ebay.com/itm/Hawk-250-Ke...s/303077495104

Worth looking at and selling a lot of these starter kits

[Megadan]

Originally Posted by NzBrakelathes

https://www.ebay.com/itm/Hawk-250-Ke...s/303077495104

Worth looking at and selling a lot of these starter kits

Answering a question with a sales pitch. And you wonder why people tend to treat you the way that they do?

Originally Posted by The_DJ_Remixer

You stated vm28...but we were talking about the vm26 - 30mm carb. Is this the correct info for the knock off vm26? TY

The pilot jet used by the knock off Mikuni VM26 is a VM28/486 style jet. Don't let it confuse you too much. It's just the same style pilot jet the VM28 happens to use, but since these are knock off carbs, they just happened to decide to use that jet style.

[2LZ]

Originally Posted by NzBrakelathes

https://www.ebay.com/itm/Hawk-250-Ke...s/303077495104

Worth looking at and selling a lot of these starter kits

Actually, that is kinda cool. I do like how you included the sprocket and plug too.

DJ, I run the "Mikuni VM26 30mm" in the link....though they come with an additional kit now too! Never had a problem with them.

https://www.amazon.com/Mikuni-Carbur.../dp/B07CN36W65

[DualSport]

I'm curious.. Why are people worried about the better EFI kit being half the order-cost of the bike itself when you eat 2/3 the cost the second you order the bike in the first place? A mint or even heavily modded&mint Hawk or Magician gets nothing but sub $500.00 offers on CraigsList and Facebook-Marketplace..

It actually makes more sense to keep one and properly set it up than to sale or part it out. Best case scenario parts appreciate a year or two from now when plastics and electronics disappear from Shenzhen markets, or a neighbor just buys it off of you on a whim..

Also as a reminder: If it's got a 48mm stud intake and switch-choke it's not a real Mikuni. Even if it says Mikuni on the stem and Japan by the bowl(this actually exists on Amazon under a China seller even though it's a trademark violation).

[Megadan]

Originally Posted by DualSport

I'm curious.. Why are people worried about the better EFI kit being half the order-cost of the bike itself when you eat 2/3 the cost the second you order the bike in the first place? A mint or even heavily modded&mint Hawk or Magician gets nothing but sub $500.00 offers on CraigsList and Facebook-Marketplace..

It actually makes more sense to keep one and properly set it up than to sale or part it out. Best case scenario parts appreciate a year or two from now when plastics and electronics disappear from Shenzhen markets, or a neighbor just buys it off of you on a whim..

Also as a reminder: If it's got a 48mm stud intake and switch-choke it's not a real Mikuni. Even if it says Mikuni on the stem and Japan by the bowl(this actually exists on Amazon under a China seller even though it's a trademark violation).

Both your question and your strange reminder were covered at least one or more times already through this thread.

Why not spend the $700 on the Ecotrons kit? Because it's more complex and requires more work than a simple $50 expenditure in a carburetor and some jets. I have nearly pulled the trigger multiple times on the Ecotrons kit, but it really isn't that necessary, and the benefits just don't seem worth it to me at least. The same can be said of the cheap EFI kits on Aliexpress as well, and they add even more potential issues into the mix.

As far as the genuine Mikuni thing... If you take notice of the posts in the thread you will see it being called a clone or knock off carb. No idea who you are trying to tell this to?

[DualSport]

Originally Posted by Megadan

Both your question and your strange reminder were covered at least one or more times already through this thread.

Why not spend the $700 on the Ecotrons kit? Because it's more complex and requires more work than a simple $50 expenditure in a carburetor and some jets. I have nearly pulled the trigger multiple times on the Ecotrons kit, but it really isn't that necessary, and the benefits just don't seem worth it to me at least. The same can be said of the cheap EFI kits on Aliexpress as well, and they add even more potential issues into the mix.

As far as the genuine Mikuni thing... If you take notice of the posts in the thread you will see it being called a clone or knock off carb. No idea who you are trying to tell this to?

Because another user in the thread linked to the same clone that clearly has Mikuni and Japan on the stem and by the Bowl. Some people who get the VM26 clones are also getting the unidentified pilot jet for some reason, so they are wasting their money on a carb that can't be completely tuned..