Carbie Tuning Time

[Cactus Jack]

Honda 100's run a #110 main and #38 pilot and 125's run a #105 main and #38 pilot in a 22 mm Keihin carb and they work perfectly in Australia . He's got a 22 mm Mikuni carb . I've found that the #38 pilot and #105 main work spot on for a ported 107 Lifan with a 22 mm Keihin carb ......... the ONLY thing you have to take into account is the fact that Mikuni uses a different method to size their jets than Keihin . So here is a jet conversion chart I just found in a web search :

Width------Keihin # -- DynoJet # -- Mikuni #
0.0350---- 92.5--------- 92--------- 86.3
0.0360---- 95----------- 94--------- 88.1
0.0370---- 97.5--------- 96--------- 90.0
0.0380---- 100---------- 98--------- 91.9
0.0390---- 102.5------- 100--------- 93.8
0.0400---- 105--------- 102--------- 95.6
0.0410---- 107.5------- 104--------- 97.5
0.0420---- 110--------- 106--------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
0.0540---- 140--------- 130--------- 121.9
0.0550---- 142.5------- 132--------- 123.8
0.0560---- 145--------- 134--------- 125.6
0.0570---- 147.5------- 136--------- 127.5
0.0580---- 150--------- 138--------- 129.4
0.0590---- 152.5------- 140--------- 131.3
0.0600---- 155--------- 142--------- 133.1
0.0610---- 157.5------- 144--------- 135.0
0.0620---- 160--------- 146--------- 136.9
0.0630---- 162.5------- 148--------- 138.8
0.0640---- 165--------- 150--------- 140.6
0.0650---- 167.5------- 152--------- 142.5
0.0660---- 170--------- 154--------- 144.4
0.0670---- 172.5------- 156--------- 146.3
0.0680---- 175--------- 158--------- 148.1
0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5

 

[themountain]

yeh i know how to check my spark plug =P haha
yeh its abit black but there is a brown tinge to it so its running about right if anything a tad rich...

well if you have a look at your main jet the are two parts to it.. you can actiolly unscrew the top of it out and thats the new bit that i got being the 95 the top bit..
the jet being two parts, ive been told it will be fine to just change the top thingie

anyone have any clue wat im talking about or do i need photos to explain?? =P

...yeah the small toppart is the main the rest is the needlejet....so you have to change the little thingy

 

[ducar.r.spec]

the top that actually screws into the carby is called the venturi pick up tube (I believe) and the part that screws into this is the jet u have to change the jet not the venturi pick up tube

 

[Cactus Jack]

The #95 Mikuni main jet is the equivalent of a #105 Keihin main jet so your jetting should work well now .............

 

[darb110]

yeh well the guy i got it off i was in there today and the lil thing that screws into the top of the main jet, changing the shall do the trick i wont have to change the bottom bit of the jet but now i need a good day to go for and spin...

and it wont be 2morra case im going to shearwater in the morning with a mate to get his ne KX250 and then GRAND FINAL =D smash the piss haha

 

[eichkay]

the top that actually screws into the carby is called the venturi pick up tube (I believe) and the part that screws into this is the jet u have to change the jet not the venturi pick up tube

If you dont know what your talking about dont be a post whore and just let someone that knows answer it. Every post ive read in the tech talk that you have answered, you dont know anything and are just posting for the hell of it and state'n the obvious.

 

[ducar.r.spec]

well sorry i was just trying to help what do u want me to do just come on here and be a freeloader

 

[Cactus Jack]

the top that actually screws into the carby is called the venturi pick up tube (I believe) and the part that screws into this is the jet u have to change the jet not the venturi pick up tube

It's called the needle jet or emulsion tube and the main jet screws into the bottom of it . I suppose that "venturi pick up tube" is another way of describing it in laymans terms .... LOL ...

Interesting link on how to tune 4 stroke carbs :

ThumperFaq: MXA Fuel Screw

4Strokes.com - Tech: Carburetor Overview

 

[themountain]

well sorry i was just trying to help what do u want me to do just come on here and be a freeloader

Don´t help!!

 

[captain dust]

It's called the needle jet or emulsion tube and the main jet screws into the bottom of it . I suppose that "venturi pick up tube" is another way of describing it in laymans terms .... LOL ...

Interesting link on how to tune 4 stroke carbs :

ThumperFaq: MXA Fuel Screw

4Strokes.com - Tech: Carburetor Overview

Thankyou for posting that, that is really helpful information. Some people should take a leaf out of your book!

 

[eichkay]

well sorry i was just trying to help what do u want me to do just come on here and be a freeloader

Misinformation is not a help, I'm sure when something goes wrong you want help from someone that knows whats going on, not some 15 year old thinking he's a qualified mechanic.

Sorry if it comes across rude but im just pointing out what a pain in the arse it is when your told the wrong thing.

 

[ducar.r.spec]

and how was i telling him the wrong thing?

 

[darb110]

haha were all getting abit roudy aint we haha =)

nah ive changed the top of the jet and its now a 95, ive set my fuel screw at 2 and a half turns out i think and ive installed a new NGK spark plug =D

seems to be running heaps better all over and definatlly better up in the high revs!! no more spitting and missing haha runs sweeeet =D

also those two websites posted by Cactus Jack are sweeet!! great info everyone give then a look =) good shit man nice find will help everyone and if not help just give them a better understanding =D


also im sorry for not posting for a lil while and i probbly wont be able to for the next few days my internets has been capped.. (N) downloaded 12 gb haha and its running so slow i couldnt even load up an internet page.. =( not happy but ill be back soooon boys and girl hopefully =D

and if your wondering im at school atm in computing bludging =D haha