Super Jet Increasing Jetting question

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
The jet sizes are in millimeters.
So for a 140, you would need a 1.4mm drill bit. Why not buy the right size jet?
 

snowxr

V watch your daughters V
Location
Waterford, MI
What brand of carb? Not all brands use the same measurements. And just buy the correct jets. They're cheap and available at nearly any motorcycle shop.
I've heard the sizing as stated by Matt E from others, but I seem to recall Mikuni's numbers actually corresponding to the number or cubic centimeters of gasoline that will frow through the jet when poured from a height of 50 centimeters over a given amount of time.

At any rate, here is a list of drill sizes (american sizes) for the most comon jets.
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
 
Last edited:
Location
Georgia
What brand of carb? Not all brands use the same measurements. And just buy the correct jets. They're cheap and available at nearly any motorcycle shop.

mikuni. Motorcycle shops carry a 140? I'll call around tomorrow but I'll still curious if drilling out the 115 would work.
 

snowxr

V watch your daughters V
Location
Waterford, MI
It will work if you have exactly the right size drill, and don't enlarge the hole at all when you drill it. Don't use a hand drill. Smart money is on the bike store having a small round Mikuni jet in stock.
 
Location
Georgia
well I couldn't find one locally and decided against drilling the old 115 out. I ordered one from atlanticjetsports.com and they lowered the shipping since it's such a small item. Great customer service there, just hard to get somebody on the phone..email is your best bet.
 

Waternut

Customizing addict
Location
Macon, GA
Lots of guys running jetski's, bikes, etc. have had success drilling jets but it's a hit or miss thing because if you drill it cocked, you will make the hole larger than desired. Atlantic jet sports is who I order my jets from and they have been really good and ship quickly. Where do you ride in GA?
 
Location
Georgia
waternut, we mainly ride allatoona....lanier sometimes. Good to hear atlantic ships quickly..I hope the jet is here by tomorrow so i can ride this weekend.
 
Location
dfw
Drilling the main jet is fine for single carb applications when you are going to power tune the top screw anyway. It is not so good for twin carbs where you are relying on both being as close as possible.
 
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