140cc lifan Engine

[kwikaz]

dont know what ur talking

how many times do i got to say i have purchased a brand new vm mikuni 26mm genuine not the chinese crap, the fake ones are not considerd vm,s ffs!! and i appriciate the advice as long as ppl know what there talking about the way i see it is you shouldnt comment when you not sure??

 

[Cactus Jack]

SGR uses Mikuni VM26 carbs !

this forum has caused me more confusion than anything, according to you cactus you say a vm 26" mikuni carb is the best for thw 140cc lifan! but now i learn that it is a two stroke carb wich is a bitch to tune thats just freaking fantastic i wish people would just help people instead of getting satisfaction of just effing people around!!

All the yanks run the genuine Mikuni VM26 round bore carbs on 141 kitted Lifan , Jialing GPX and Zongshen 4 stroke engines so nobody gave you the wrong advice .

You should email SGR to ask what jets they're running in VM26 carbed 140 cc chinese engines (at sea level) . Your VM26 should have the mixture screw right near the air filter flange on the fuel tap side of the bike !

Info straight off the SGR site : 141 Bore Kit with 26mm Mikuni VM26 Carb/Kit - For engines with 52.4X55mm bore and stroke (120cc). Must have 14mm Piston pin. Engines they will fit - Zongshen and Lifan 120.

sgr-usa.com

Also ~ Check these Miconi (Mikuni) VM26 round bore copies out . Since there's no complaints , they must be jetted close enough for people to be happy : # main jet: 1.2mm and # vice jet : 0.39mm

eBay Australia: Carbi 26mm Miconi upgrade for Pit bike Mini Dirt bike (item 270112381804, end time 24-Apr-07 17:23:04 AEST)

And also keep it in mind that people on this site have found their 140's to run best with a #102.5 to #105 main jet in the oval bore 26 Mikunis which everyone calls "30's" and the 22 oval bore carbs which everyone calls "25's or 26's" .

Let's try to stay positive about this now !!!!! When you get your carb jetted right you can then tell everyone else how to tune a genuine Mikuni VM26 round bore carb ......... That's what forums are all about . NOBODY knows everything ........we can only tell what we DO know and hope it helps other people out .

 

[kwikaz]

sorry

sorry if im getting annoyed its just i dont know what to believe? what does sgr stand for?? and them facts are for a 54x55 engine when mine is 55 bore and 59 stroke??

 

[Cactus Jack]

sorry if im getting annoyed its just i dont know what to believe? what does sgr stand for?? and them facts are for a 54x55 engine when mine is 55 bore and 59 stroke??

SGR stands for Staggs Goodwin Racing USA - yes your engine is 55 x 59 = 140 cc but they are boring the Lifan engines to 57 x 55.5 = 142 cc and the GPX Jialings to 57 x 57 = 145 cc and still using the same VM26 Mikuni round bore carb and manifold kit that you've got ~ so the capacity is about the same .

Is the inlet manifold that came with the Mikuni VM26 kit - 26 mm all the way through ?

Here's some Mikuni jetting info :

Sudco Mikuni Jets

mikuni jets

mikuni pilot jets

http://www.sudco.com/Diagrams123/vm26-606.gif

 

[kwikaz]

manifold

i actually bought a takegawa inlet manifold 26mm.. its the long type i h8 this forum its hard to post pictures other wise id have a heap of pics for you..

 

[Mack]

open a free pic hosting account and link back

 

[kwikaz]

small

yer but they have to be small or this forum will not accept??? i like big pictures for all the cavemen out there lmao...

 

[Cactus Jack]

i actually bought a takegawa inlet manifold 26mm.. its the long type i h8 this forum its hard to post pictures other wise id have a heap of pics for you..

OK good , you got the right manifold ! So it's just a simple matter of jetting the carb right and the best way is to find out what they put in them over in the US where everyone is running VM26's or you can try Aussie shops like - ozmini50's - big50.com - scootoz etc

For the cash people charge for those carbs you'd at least expect them to jet them close to suit the engine they're claiming they're for instead of handing you a carb straight from Mikuni - the VM26 comes supplied with a #190 main jet = 1.192 mm and a #60 pilot = .670 mm !


PRO-FLO MIKUNI ROUND SLIDE CARB SPECS

 

[kwikaz]

huge

yes that main jet is effing ginormass!! i dont know much about carb jetting but when i read what main jet my carb was coming with i thought that can not be right?? so thanks for confirming my suspisions so what should i use a 1.02 or a 1.05? or niether to start with?? i hope the thing comes with some sort of instructions but i dont think it will?? p.s take a look at what all the fuss is about?

 

[Cactus Jack]

Jet size chart !

I've done some searching and found that the jet number size does NOT equal the size in mm as I've been led to believe . I found it while trying to find a Mikuni to Keihin jet size comparison chart to see if they both use the same jet sizing scale or not . According to the chart - a 1.2 mm main jet = about a #195 main and a .39 pilot jet = a #20 pilot

Allens Performance Mikuni &#38 Keihin Carbs

Mikuni carburetor operation and tuning

 

[foolsp33d]

sweet bike Kwik!! very cafe racer i like it! get some slicks but! How do you go with the kick starter? looks like would hit on your pegs...

 

[Cactus Jack]

Cool bike ! Are you going to drag race it or something ?? That pipe looks really good . How big is it out of the head ?
You've already got 24/28/ and 30 OKO's - so what have you found with them ?? They run #38 pilot and #105 main according to DHZ's listings !

 

[kwikaz]

pegs

nah doesnt hit the pegs its a takegawa kick starter, so its designed to clear all that stuff,as for the oko,s the 24mm came with a 1.07 main, and a 38mm pilot. the 30mm came with a 1.05 main and 39 pilot,the 28mm came with 1.02 main and 38 pilot, but i swaped the 1.05 out the 30mm oko and put it into the 24mm oko?? and thanks for the complements on my monkey, wont take it to drag strip but i want it to go as fast as i can get it.. p.s i got road tyres coming there going to be fatter than the originals 4" wide..

 

[cass38a]

Jet sizes have something to do with how much fluid will flow thru in one minute at sea level (or some other cocked up measure) not the size of the hole.

 

[kwikaz]

help

that info might help a mechanic?? but that dosnt make no sense to me at all??

 

[themountain]

Its easy...Mikuni jets have some sort of specific flowrate and Keihin jets diameters..to compare the things look onthe twobrother website...there are all the jets listed ....and like I wrote in my first post..try 190 Main and the 17.5 Pilot which came with the carb!!

BTW....if you want the ultimate solution get an Keihin FCR28....

PS: ...whats your gearing, by the way???

 

[Cactus Jack]

Jet drills and self proficiency !

Jet sizes have something to do with how much fluid will flow thru in one minute at sea level (or some other cocked up measure) not the size of the hole.

Yes , that's dead right - it's CC/Min of flow ! The reason why it's good to know the actual jet hole size is so that you can buy a set of jet drills to save on headaches and frustration by drilling your own jets out to whatever size you require once you've worked out what jets work for a particular application . Also - if you have an existing jet combination that works but the jets have no numbers on them - you can work out what sizes they are by measuring the holes with the drill bits .

No need to throw jets away - you can drill smaller jets bigger to suit and you could also probably solder bigger jets up then redrill them to a smaller size if you can't find or buy the proper sized jet . Think about what I've said for a minute - it's all about becoming self proficient - once you understand what I've said and take it up - you'll never need to ask anyone elses' advice on jetting ever again - you'll be able to figure it out for yourself . You could ask 10 different racers with the same carbs what jets they're running and get several different answers . Another piece of good advice is to keep a log of what you find does and doesn't work for your own future reference .

 

[Cactus Jack]

Its easy...Mikuni jets have some sort of specific flowrate and Keihin jets diameters..to compare the things look onthe twobrother website...there are all the jets listed ....and like I wrote in my first post..try 190 Main and the 17.5 Pilot which came with the carb!!

BTW....if you want the ultimate solution get an Keihin FCR28....

PS: ...whats your gearing, by the way???

The 190 is most likely needed because the bore hole thru the slide is a lot larger than with oval bore carbs . Yes I've also mentioned the FCR 28 but they're around $1,000 AUD ! They'd work great on a road bike . There's a guy on TT (shawn mc) who says he can produce a fuel injection setup for pit bikes for $600 US . Tuned Port Fuel injection would really increase the power and throttle response by stacks because it doesn't rely on intake velocity to work like carbs do !

 

[kwikaz]

malarki

its all MALARKI!!

 

[Cactus Jack]

its all MALARKI!!

With that type of attitude dude - you'll learn NOTHING and the rest of your life will be MALARKI . How old are you anyway - I was racing worked XR75's when I was 13 and I had to learn how to do engine work myself because I lived with my pensioner grandmother and never had a father to teach me anything . Keep an open mind !

Mechanical Fuel injection - ThumperTalk