honda305 Home honda305 Auctions honda305 Gallery honda305 Forum


honda305.com Forum

Login
□ Search
□ FAQ 
□ 
Vintage Honda Owners,
Restorers, Riders and
Admirers

Carb Curve Ball - The bane of my existance! ;) OPINIONS NEED

Fuel System: Gas (Petrol) tanks, Carburators
User avatar
davomoto
honda305.com Member
Posts: 2508
Joined: Sat Nov 18, 2006 7:36 pm
Location: Marin County CA

Post by davomoto » Fri Jan 28, 2011 3:57 pm

Sascha wrote:I have aboslutely no idea how to do that... is there a reference you can point me to?

-sascha
Sasha, which part do you have no idea how to do?

Davo
davomoto
64 CB77
63-7 CB77 Cafe'
67 CL77
64 CL72
66 CL77 big bore flat tracker
Many others!

Hahnda
honda305.com Member
Posts: 835
Joined: Wed Nov 02, 2005 2:36 pm
Location: Cameron, WI

Post by Hahnda » Fri Jan 28, 2011 6:15 pm

You say the slide moves up and down freely. Is that with the carb on or off the bike. Sometimes when you tighten the nuts that hold the carb on it will slightly distort things. If it slides up and down easily while the carb is on the motor then this isn't your problem.

User avatar
Snakeoil
honda305.com Member
Posts: 1150
Joined: Wed Aug 04, 2010 6:45 pm
Location: Upstate NY

Post by Snakeoil » Fri Jan 28, 2011 9:44 pm

Great point. Pull the air filters off look down the throats and see where the slides are. Rev the bike and see if they return to rest or stay up in the bores.

This is the kind of thing that is just a matter of thinking about everything that is associated with the mechanical piece and checking each one out. It's not a guess the right answer kind of thing.

There are all kinds of things that could be at play here. Cables sheaths could be popping out of a socket. Cable might be binding in the twist grip. Slide bores could be distorted and on and on. But you can't guess at what is doing it. First symtom is prolonged rev when twist grip is closed. To figure out what is going on, you follow a process of elimination. Are the slides closing is the first thing to check. So pull the filters and confirm. If they are, then you have an air leak. If they are not, figure out why. Can you slide them up and down with the engine not running with the twist grip. Can you do the same by putting your fingers in the throats and pushing them up and let them return? The turning of the handlebars is one I forgot about, but is a classic problem for first time tuners. They adjust the cables too tight and with the bars hard right or left, the cables are too tight and pull up the slides and rev the bike.

Work thru the mechanics, Sascha. That's how you learn. Work thru this and next time you'll be that smarter when you have to figure it out.

Good luck,
Rob

Loudo
honda305.com Member
Posts: 175
Joined: Sun Dec 07, 2008 9:57 pm
Location: Seattle, Washington

O-rings?

Post by Loudo » Mon Jan 31, 2011 7:22 pm

Sascha, what is the condition of the o-rings at the carb/head junction? New o-rings at this location can often solve frustrating air leak issues. I should know.

Vince Lupo
honda305.com Member
Posts: 1371
Joined: Wed May 04, 2005 7:17 am

Post by Vince Lupo » Tue Feb 01, 2011 6:18 pm

Let me ask the question (as I considered it in another thread of yours regarding this issue) -- is it possible that the mechanical advance is sticking? Can anyone else confirm that this could possibly cause this phenomenon?

I had this exact thing happen a few years ago on my SuperHawk, and it turned out to be my mechanical advance (old worn-out springs not allowing the advance to return to full retard). Just a thought......

Dgormley
honda305.com Member
Posts: 405
Joined: Tue May 19, 2009 12:31 am
Location: Tacoma Wa

Correct

Post by Dgormley » Tue Feb 01, 2011 9:48 pm

Vince, you are correct. My warn out advance springs did the same thing. Once they were changed out it ran/runs perfect......................................D

Sascha
honda305.com Member
Posts: 340
Joined: Mon Sep 27, 2010 12:36 pm
Location: Toronto, Canada

Post by Sascha » Tue Feb 22, 2011 3:53 pm

I dont know where these springs are located or how to check them... anyone have pictures!?

Post Reply




 

CB-77 | CYP-77 | Road Test | Riding Log | Literature | Zen | Marketplace | VJ Survey | Links | Home