NT carb - basic and speed jet size

Chaz

Well-Known Member

Jun 3, 2012

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Vancouver, British Columbia

Nov 6, 2016

• #1

I've done some research here and am still unsure about whether or not there is a different size jet for the stock basic nt carb compared to the nt speed carb. Has somebody measured? I don't have the tools to measure myself.

thanks,

Chaz

 

MotorBicycleRacing

Well-Known Member

Jul 28, 2010

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SoCal Baby!!!

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Nov 7, 2016

• #2

I found that they were the same, 70.

 

Chaz

Well-Known Member

Jun 3, 2012

1,004

72

48

Vancouver, British Columbia

Nov 7, 2016

• #2

Thanks for the reply, MBR. I guess I'm going to have to get a pin vise and micro bits to dial this thing in.

 

Last edited: Nov 7, 2016

Agreen

Member

Feb 10, 2013

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Southeastern GA

Nov 7, 2016

• #3

I found biknut's dissertation on the speed carb. Up until now, I thought they were identical with the exception of the filter.

http://motorbicycling.com/showthread.php?t=37986

 

Chaz

Well-Known Member

Jun 3, 2012

1,004

72

48

Vancouver, British Columbia

Nov 7, 2016

• #4

Thanks for posting that link, Agreen. I can see the throat is bigger on the speed carb if I look at them side by side. I was hoping the stock carb had a smaller jet.

I suppose I should just bust open my wallet and get my yz80 expansion chamber put on. If I do that, with any luck I might get away without having to change jets.