Re: [Honda-C70] After market carb

 

I can only imagine that everything on the bike is up to par because the day I parked the bike before it was clogged,I had no problem going 45mph on straight,flat roads.I can only assume everything else is ok.Joey

Joey Pafumi

--- On Wed, 10/5/11, tch@peoplepc.com <tch@peoplepc.com> wrote:

From: tch@peoplepc.com <tch@peoplepc.com>
Subject: Re: [Honda-C70] After market carb
To: Honda-C70@yahoogroups.com
Date: Wednesday, October 5, 2011, 4:11 AM

 

Sort of. That's a wide disparity, speaking theoretically -- 88 vs. 72 -- you should check the hole diameter for both, though, using a small drill bit. What I meant was a #88 "Mikuni" will flow about 10% more fuel than a "non-Mikuni" with the same size diameter hole. Also, the jets should be stamped with the manufacturers name on them.

But back to your bike. If your points, timing, valves, tensioner, spark plug gap, and carb float level are adjusted correctly, and your electrical system is in good working order, and your air filter is clean, and the gas cap is venting properly, and there are no intake manifold leaks, then use the larger of the two main jets that you mentioned at the beginning of your post. My guess is that your problem is similar to others, but not all, who've used an aftermarket carb -- the main jet is too small. Good luck and keep us posted.

-----Original Message-----

>From: Joseph Pafumi <joeypafumi@yahoo.com>

>Sent: Oct 4, 2011 11:57 PM

>To: Honda-C70@yahoogroups.com

>Subject: Re: [Honda-C70] After market carb

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>The service manuel states that the main jet is #88--The jet in my new carb is #72---Would that be the difference you've previously discussed about the "Mikuni" jet in my old carb? Thanks!!

>

>Joey Pafumi

>

>--- On Mon, 10/3/11, tch@peoplepc.com <tch@peoplepc.com> wrote:

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>From: tch@peoplepc.com <tch@peoplepc.com>

>Subject: Re: [Honda-C70] After market carb

>To: Honda-C70@yahoogroups.com

>Date: Monday, October 3, 2011, 12:41 PM

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> Just make sure before switching main jets that the main jet in your old carb is stamped "Mikuni". Good luck.

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>-----Original Message-----

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>>From: Joseph Pafumi <joeypafumi@yahoo.com>

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>>Sent: Oct 3, 2011 3:04 PM

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>>To: Honda-C70@yahoogroups.com

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>>Subject: Re: [Honda-C70] After market carb

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>>OK! My main jet is fine, in my original carb.The slow jet was the one that was clogged and thus drilled out.I will do this.Thanks  a lot!!!  JOey

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>>Joey Pafumi

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>>--- On Mon, 10/3/11, tch@peoplepc.com <tch@peoplepc.com> wrote:

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>>From: tch@peoplepc.com <tch@peoplepc.com>

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>>Subject: Re: [Honda-C70] After market carb

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>>To: Honda-C70@yahoogroups.com

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>>Date: Monday, October 3, 2011, 5:33 AM

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>> I believe the original carb came with a Mikuni main jet, but the replacement carb has a main jet other than Mikuni. The punch line is: Mikuni main jets flow about 10% more fuel than the same size (number) main jet of another manufacturer because Mikuni main jet sizes are based on actual fuel flow rather than the the hole diameter. This is the primary reason for the reduction in top-speed that many C70 owners experience when replacing the original carb with an aftermarket one. So, replace the main jet in the aftermarket carb with the Mikuni main jet found in your original carb, put the needle in the middle groove and work from there.

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>>-----Original Message-----

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>>>From: cayman2653 <cayman2653@yahoo.com>

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>>>Sent: Oct 3, 2011 7:59 AM

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>>>To: Honda-C70@yahoogroups.com

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>>>Subject: [Honda-C70] After market carb

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>>>Earlier this summer I replaced the Honda Carb on my 81 Passport with a after market carb from dratv. It runs good but is not completely right. The bike runs right up to 33-35 mph and seems to studder (?), like its running out of gas or out of time maybe. There are lots of instructions on how to set up a Honda carb on this site and they work very well. But I don't think the settings are the same for the dratv carb. Does anyone know what groove the needle should be set in? What should the main jet size be? The bike idles very smooth and slow; it will rev right up in first and second gear but seems to run out of power in third gear. Gearing is stock, 15-36, and the engine has about 200 miles on a upper end rebuild.

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>>>------------------------------------

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>>>C70 Passport Not Running Right?

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>>>1970-73 C70 Honda Service Manual: http://tinyurl.com/6ebwtw

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>>>1970-73 C70 Troubleshooting Guide:

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>>>http://tinyurl.com/6ebwtw (scroll to sec.7.1 page 101.jpg)

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>>>1980-83 C70 Honda Service Manual: http://tinyurl.com/hu42c

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>>>1980-81 C70 Troubleshooting Guide:

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>>>http://tinyurl.com/hu42c (scroll to sec.18-1 page 170.jpg)

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>>>1982-83 C70 Troubleshooting Guide:

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>>>http://tinyurl.com/hu42c (scroll to sec. 20-28 page 205.jpg)

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>>>1980-81 C70 Maintenance Schedule: http://tinyurl.com/z4zn6

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>>>1982-83 C70 Maintenance Schedule: http://tinyurl.com/hw35c

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>>>More resources for C70 Passports and Cubs:

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>>>http://www.shlaes.com/Vehicles/Scooter.htm

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>>>http://www.velodrome.com/HondaC70/HondaC70.htmlYahoo! Groups Links

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>>TC

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>>________________________________________

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>>PeoplePC Online

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>>A better way to Internet

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>>http://www.peoplepc.com

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>>------------------------------------

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>>C70 Passport Not Running Right?

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>>1970-73 C70 Honda Service Manual: http://tinyurl.com/6ebwtw

>

>>1970-73 C70 Troubleshooting Guide:

>

>>http://tinyurl.com/6ebwtw (scroll to sec.7.1 page 101.jpg)

>

>>1980-83 C70 Honda Service Manual: http://tinyurl.com/hu42c

>

>>1980-81 C70 Troubleshooting Guide:

>

>>http://tinyurl.com/hu42c (scroll to sec.18-1 page 170.jpg)

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>>1982-83 C70 Troubleshooting Guide:

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>>http://tinyurl.com/hu42c (scroll to sec. 20-28 page 205.jpg)

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>>

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>>1980-81 C70 Maintenance Schedule: http://tinyurl.com/z4zn6

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>>1982-83 C70 Maintenance Schedule: http://tinyurl.com/hw35c

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>>More resources for C70 Passports and Cubs:

>

>>http://www.shlaes.com/Vehicles/Scooter.htm

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>>http://www.velodrome.com/HondaC70/HondaC70.htmlYahoo! Groups Links

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>TC

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>________________________________________

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>PeoplePC Online

>

>A better way to Internet

>

>http://www.peoplepc.com

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>[Non-text portions of this message have been removed]

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>------------------------------------

>

>C70 Passport Not Running Right?

>1970-73 C70 Honda Service Manual: http://tinyurl.com/6ebwtw

>1970-73 C70 Troubleshooting Guide:

>http://tinyurl.com/6ebwtw (scroll to sec.7.1 page 101.jpg)

>1980-83 C70 Honda Service Manual: http://tinyurl.com/hu42c

>1980-81 C70 Troubleshooting Guide:

>http://tinyurl.com/hu42c (scroll to sec.18-1 page 170.jpg)

>1982-83 C70 Troubleshooting Guide:

>http://tinyurl.com/hu42c (scroll to sec. 20-28 page 205.jpg)

>

>1980-81 C70 Maintenance Schedule: http://tinyurl.com/z4zn6

>1982-83 C70 Maintenance Schedule: http://tinyurl.com/hw35c

>

>More resources for C70 Passports and Cubs:

>http://www.shlaes.com/Vehicles/Scooter.htm

>http://www.velodrome.com/HondaC70/HondaC70.htmlYahoo! Groups Links

>

>

>

TC

________________________________________

PeoplePC Online

A better way to Internet

http://www.peoplepc.com

[Non-text portions of this message have been removed]

__._,_.___
Recent Activity:
C70 Passport Not Running Right?
1970-73 C70 Honda Service Manual: http://tinyurl.com/6ebwtw
1970-73 C70 Troubleshooting Guide:
http://tinyurl.com/6ebwtw (scroll to sec.7.1 page 101.jpg)
1980-83 C70 Honda Service Manual: http://tinyurl.com/hu42c
1980-81 C70 Troubleshooting Guide:
http://tinyurl.com/hu42c (scroll to sec.18-1 page 170.jpg)
1982-83 C70 Troubleshooting Guide:
http://tinyurl.com/hu42c (scroll to sec. 20-28 page 205.jpg)

1980-81 C70 Maintenance Schedule: http://tinyurl.com/z4zn6
1982-83 C70 Maintenance Schedule: http://tinyurl.com/hw35c

More resources for C70 Passports and Cubs:
http://www.shlaes.com/Vehicles/Scooter.htm
http://www.velodrome.com/HondaC70/HondaC70.html
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