Not reaching top speed

GoldenMotor.com

thirdorangutan

New Member
Mar 19, 2015
74
0
0
Austin, Texas
I would highly recommend that you just buy the Dellorto jets
and do not mess with soldering and drilling jets.

The #72 drills a 63 jet
Some 68, 66, 64 and 62 jets will cover you.
I would try the 66 first as the stock jet is a 70.

Only $2.50 each from Sick Bike Parts.
http://www.sickbikeparts.com/catalo...ucts_id=116&osCsid=e5kj8fd6algc5r98oa555tcj90


#BitSize Inches Millimeters Jet Size

#80 0.0135 0.3429 34.29
#79 0.0145 0.3683 36.83
1/64" 0.0156 0.3969 39.69

#78 0.016 0.4064 40.64
#77 0.018 0.4572 45.72
0.5mm 0.0197 0.5 50

#76 0.02 0.508 50.8
#75 0.021 0.5334 53.34
#74 0.022 0.5715 57.15

#73 0.024 0.6096 60.96
#72 0.025 0.635 63.5
#71 0.026 0.6604 66.04

#70 0.028 0.7112 71.12
#69 0.0292 0.74168 74.168
0.75mm 0.0295 0.75 75

#68 0.031 0.7874 78.74
1/32" 0.031 0.7938 79.38
#67 0.032 0.8128 81.28

#66 0.033 0.8382 83.82
0.85mm 0.0335 0.85 85
#65 0.035 0.889 88.9
The reason Im not just buying one is i want to be able to try different sizes, without having to buy a new jet every time. Why do you suggest just buying one?
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,844
109
63
SoCal Baby!!!
www.facebook.com
The reason Im not just buying one is i want to be able to try different sizes, without having to buy a new jet every time. Why do you suggest just buying one?
look at the drill sizes, you can't drill a 68 or a 62 jet.

Once again, a 68 , 66, 64, 62, will cover you for only $10 for well made jets.
It's a sale price so now is a good time to stock up. ;)
Stock is a 70
Frankly a hand drilled jet is not as good as a Dellorto jet.
do you know how to solder and have one?
 
Last edited:

thirdorangutan

New Member
Mar 19, 2015
74
0
0
Austin, Texas
Yes i know how to solder, and have a soldering iron. I see how a hand drilled jet isn't as precision, but just like the freedom of being able to change my jet size without having to bring out more cash.
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,844
109
63
SoCal Baby!!!
www.facebook.com
I've already ordered them, but they get here in mid April. Little too long of a wait. Do you think home depot or lowes has them? If they do, I'll cancel my order.
Sounds like you ordered cheap drill sets from China.
They are junk.
Where did you order the bits from and how much were they?

home depot or lowes do not carry those bits.
Maybe a good hardware store.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Sounds like you ordered cheap drill sets from China.
They are junk.
Where did you order the bits from and how much were they?

home depot or lowes do not carry those bits.
Maybe a good hardware store.
Those bits from widget are excellent bits, they do a great job, been using them for several years and soldering and drilling the jet yourself is the best way to get things where they need to be, people need to stop adding and adding to the point of creating confusion here and just let the guy get his bits and do the work to get the carb jet size right.

it has already been confirmed that the CHINESE made jets we have available for these carbs are way more hit and miss than just soldering and drilling your own jet, I can garrantee that a jet drilled with either a #72 or #73 will get his engine pretty much where it likely needs to be for his basically stock set up.

some of us have been steady trying to help get this all worked out and then others have nothing to add but to come in and try to shoot down the recommendations of the people who have spent the most time here trying to guide the OP in the right direction with proven solutions.
 
Last edited:

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Thanks @mapbike, you're so helpful
Just hang in there, dont second guess or worry to much right now about any of it, gotta focus on just getting that main jet sized down and making sure all the gaskets are sealing good and unless there is something else wrong that we haven't addressed yet you'll have a much better running bike soon.

I can't promise 37mph since top speeds which sometimes dont happen without some other modifications which is usually at least a better flowing exhaust, but since you've done a couple mods that may have that exhaust flowing better already, its possible you may have a 30+mph bike once the engine isnt getting drowned in fuel and can actually get a good steady breath of the correct air fuel mixture so it can rev on up to its potential.
 
Last edited:

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
The bits from widgetsupply will do just fine, if you can find these size bits at a hardware store even better... also try an electronics tool and supply store if you have one in your area as they usually carry these smaller bits.
These carbs are compatible with the 5mm dellorto jets and this is another option if you can get a few before the bits come in. Just get these in sizes from 64 up to 70, these are different from the drill size so the smaller the number the smaller the hole.
It's best to have a few extra jets so you can experiment or you can pre drill to save time dialing these in.

It doesn't matter which way you do it whether you buy an assortment of jets or drill them yourself, both ways work and you'll know when you got the right one in.
Not everyone has the budget to buy a bunch of jets and not everyone can solder or drill a straight hole so you do have options and whichever way you choose, you will know when the engine is getting the right amount of fuel thru the carb.
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
I agree with map too... don't let these others come in and misguide you who haven't been trying to help other than to insert themselves into this after good advise has already been given. There are a few who just crave attention and others who think you need the most expensive parts before something as simple as drilling get a jet will fix your problem...
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
I agree with map too... don't let these others come in and misguide you who haven't been trying to help other than to insert themselves into this after good advise has already been given. There are a few who just crave attention and others who think you need the most expensive parts before something as simple as drilling get a jet will fix your problem...
Bingo...... folks we have us a winner.....ding ding ding......!

or I guess I could have just said Ditto......lol!
 

Davezilla

New Member
Mar 15, 2014
2,705
10
0
San Antonio Texas
Sounds like you ordered cheap drill sets from China.
They are junk.
Where did you order the bits from and how much were they?

home depot or lowes do not carry those bits.
Maybe a good hardware store.
I got a few of these bit sets and they work great, these are hard to find in sizes smaller than 60 unless you order a set of cobalt bits from a supplier that won't sell just a handful but will sell you 100 of each size. If someone is just drilling thru solder they will work and last just fine. And by the way I can measure mine with my digital mitutoyo calipers if you think the sizes are that far off.... even if they are a ten thousandth or so off, an engine will never know the difference.
Myself and plenty of others have successfully soldered and drilled jets to tune our carbs, and myself and others have done just fine spending 2 to 5 bucks per jet to dial them in as well. It's definitely more sensible money wise to buy a handful of nt jets and solder them shut then redrill.
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,844
109
63
SoCal Baby!!!
www.facebook.com
I agree with map too... don't let these others come in and misguide you who haven't been trying to help other than to insert themselves into this after good advise has already been given. There are a few who just crave attention and others who think you need the most expensive parts before something as simple as drilling get a jet will fix your problem...
3 jets at $2.50 each is expensive parts? laff
He already bought a new speed carb for a lot more.

Actually a 66 jet would be the best bet.
68, 66, 64.
You can't even drill a 68 hole with these bits.

Other people are reading this that don't wanna mess
with soldering jets and drilling them.

Yeah, I posted the chart of jet sizes to drill bit #'s and their sizes. :)
Quite an ego you have there and looks like you are getting paid by the word?
 

MotorBicycleRacing

Well-Known Member
Jul 28, 2010
5,844
109
63
SoCal Baby!!!
www.facebook.com
Recently my friend and I both bought 66cc flying horse motors and put them on micargi panteras. He has a 90 degree billet and a speed nt carb and I have the stock nt carb and billet. We both recently tested our top speeds. My bike reached 23 miles per hour and his reached 37. .
Did you both buy the same kit from the same dealer?
Do they both have the same exhaust? rear sprocket?