RE: [Honda-C70] Re: 1981 c70 carb problems

Bob : 1 last thought. Is the plug in the bottom of the drain hose hanging down from the side of the PCV valve that is connected to the air plenum ? The PCV sucks crankcase vapor & might affect the mixture ,but I can`t think it would be much. I am stumped . Good Luck! Baby Huey PS I will probably count carburetors all night instead of sheep!

To: Honda-C70@yahoogroups.com
From: bobdaly57@yahoo.com
Date: Fri, 20 May 2011 00:35:25 +0000
Subject: [Honda-C70] Re: 1981 c70 carb problems

Good thought. I checked the choke, it opens and closes correctly.
Thanks
Bob

--- In Honda-C70@yahoogroups.com, myron andrews <mvandrews13@...> wrote:
>
>
> Bob : Is the choke working correctly ? The butterfly in the end of the carb should close when choke is on & be flat in the end of the carb when off. There is a spring on the out side of the carb that lets the choke plate float open some at higher rpm so you can ride while the motor warms up but will snap the choke shut when rpm`s drop. With no restriction the carb may be able to over come the spring & breath ,but with the plenum tube or air cleaner in place it chokes off . This is just a guess . Good Luck ! Baby Huey
>
>
>
> To: Honda-C70@yahoogroups.com
> From: bobdaly57@...
> Date: Thu, 19 May 2011 16:09:44 +0000
> Subject: [Honda-C70] Re: 1981 c70 carb problems
>
>
>
>
>
>
> Sorry, you are correct. The passport runs great with the aftermarket
> Carb only if the rubber tube to the frame
> Is disconnected. If you remove the air filter
> And leave the rubber tube connected it still
> Will not run well. I checked and made sure
> There is no obstruction in the tube or frame and it's clear.
> I phoned the store I purchased the carb from
> And he thinks it's defective or the float in not set correctly.
>
> Thanks
> Bob
>
> --- In Honda-C70@yahoogroups.com, myron andrews <mvandrews13@> wrote:
> >
> >
> > Bob: You have more compression than my 81 had 10 years ago so I assume that is not a problem. But your post gets confusing when you say " Runs perfect if the intake manifold is disconnected " . The intake manifold is the metal tube bolted to the head & carb . If it was loose you would have a vacumn leak that would cause problems in tuning & running . So I must assume that what you are talking about is the rubber intake plenum. You also mentioned removing the air cleaner with no change. Are you talking about the air cleaner cover , the paper filter , or the whole air filter box from the frame ? Someone didn`t have a nut on the paper filter then the cover with the chrome acorn nut that self limits how tight the cover can be tightened & had sealed the air box so tightly there was only the small cut out on the cover to breath. Check that the rubber air tube isn`t plugged inside or rotted so it sucks flat when reved. Also check that the exhaust is not plugged . Mike G posted a pic of a wasp nest in the end of his muffler. An insects version of [potato in the tail pipe trick] it might start but can`t rev. Good Luck! Baby Huey
> >
> >
> >
> > To: Honda-C70@yahoogroups.com
> > From: bobdaly57@
> > Date: Tue, 17 May 2011 13:32:37 +0000
> > Subject: [Honda-C70] 1981 c70 carb problems
> >
> >
> >
> >
> >
> >
> > Replaced carb with aftermarket after a rebuild did not resolve
> > a problem. With the after market carb the passport
> > Runs perfect if the intake manifold is disconnected
> > With the manifold connected it idles great but
> > Bogs down when you accerate. If you remove the air cleaner
> > It does not change anything, but if you disconnect the rubber
> > Intake tube at the carb the bike runs perfect.
> > When you pull the plug it's black so I assume it's
> > Running rich. I have tried to adjust the air screw
> > But no setting improves the problem.
> > The passport has 18,000 miles on it with
> > A compression of 140 psi.
> >
> > The specs on the new carb are:
> > Main jet 72
> > Pilot jet. 35
> > Intake16mm
> > Needle set p107
> > The carb is off eBay from Win cycles.
> >
> > Is the compression to low and not sucking in enough air?
> >
> > Any other ideas?
> >
> > Thanks
> > Bob
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
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> [Non-text portions of this message have been removed]
>

[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
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