Flat spot off idle

This is where discussions of EFI systems, Dual Carbs, Single Carb mods and plans can be discussed and shared.

If you are working on or have a problem with stock carbs then your questions do not belong here, please post them in the Goldwing Tech Discussions Forum.

Moderators: sunnbobb, Neil, Forum Moderators

Post Reply
Rich1764@yahoo.com
Lead Member
Lead Member
Posts: 8
Joined: Fri Apr 08, 2016 8:48 pm

Flat spot off idle

#1

Post by Rich1764@yahoo.com »

I purchased and installed a single carb. manifold and carb. from SC Conversions. I'm happy with the set up. In Bill Gratzl's instructions he has a suggestion that to get the engine to idle better one might try plugging the hole in the throttle plate. This did not work for me. The carb was basically untunable until I opened the throttle plate hole. I set the volume and bypass as suggested and everything worked as advertised. The one issue that I still have is a stumble off idle. and some flat spots as the engine RPMs increase. The bike runs OK the stumble and flat spots are more of an annoyance. I have tried to adjust the volume screw out to fatten up the mixture, without much success. I have raised the idle via the bypass which seemed to help some. I don't know if the stumbles are cause by a too lean mixture or a too rich mixture. I will continue to tweak the settings, but I was wondering if anybody else has dealt with this problem and if there are any cures. Any suggestions would be appreciated. :?:
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Flat spot off idle

#2

Post by ericheath »

Have you done some searches in the Unique Carburetion forum. There are guys who've done it.
What model carburetor might generate some responses along with "single carb" in the subject line. You can modify the title by clicking the first post.

Quite a few guys who have done it at classicgoldwing.com. More recent builds than here.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
Hukmut
Billet Alum. Member
Billet Alum. Member
Posts: 206
Joined: Mon Feb 17, 2014 5:02 pm
Location: Wiggins,MS USA

Re: Flat spot off idle

#3

Post by Hukmut »

Do not use the Solex 34pict3. They are crap!
Yes, it IS my opinion. But, having said that: my 25+ years of rebuilding VW products sorta, almost, gives me something to base my opinion on.
They were crap when they came out in '73 and they are still crap.
Go with the Holley/Weber. You will be miles/$ ahead with far fewer problems.
I'm done.
Ride safe, y'all!




p.s. I no longer fix VWs. Too busy fixin' my gl. :-)
Experience is what you get when you didn't get what you wanted.
Do your work with your whole heart and you will succeed! There is so little competition.
Come to kindly terms with your ass, for IT bears YOU!

1999 Valkyrie built from parts. One owner. :crosso
1981 gl1100 naked, Cosicud. :orange Sold!
1981 gl1100 naked. New project. :-D
Hukmut
Billet Alum. Member
Billet Alum. Member
Posts: 206
Joined: Mon Feb 17, 2014 5:02 pm
Location: Wiggins,MS USA

Re: Flat spot off idle

#4

Post by Hukmut »

Oh, but if you are using the H/W setup, just enlarge the primary idle jet. Had to do that on the VW bus conversions. The runners were a lot longer and it took too long for the fuel to get where it needs to be. Hope that helps.
Sorry for the previous rant.
Experience is what you get when you didn't get what you wanted.
Do your work with your whole heart and you will succeed! There is so little competition.
Come to kindly terms with your ass, for IT bears YOU!

1999 Valkyrie built from parts. One owner. :crosso
1981 gl1100 naked, Cosicud. :orange Sold!
1981 gl1100 naked. New project. :-D
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “Unique Carburetion”