No starting power - low rpms

[bennettj]

I 'saved' a bike from 15 years in a barn and, now that I've rebuilt carbs, have it running. One problem though. I have very little to no power in first gear until the bike has gained some speed. In other words, I have little power at low rpms. Bike also needs to warm up ten minutes before it has any power. Bike runs great above 3000 rpms, once warm. When rebuilding carbs I found the factory set air screws to be at 1 and 3/4 turns, but read (I think on this sight) to set screws at 3 and 1/2 turns. So I did. And it runs - but no power at low RPM's. Any suggestions?

[almarconi]

Hello and welcome to the forum.

First off, what year and model bike are you working on?

[chef1366]

Pull the carbs, split the rack, tear down each body and dip in Berrymans.
Get new o-rings from Mr. Barr.

http://www.cycleorings.com/

http://www.thegsresources.com/gs_carbrebuild.htm

[BassCliff]

Greetings and Salutations!!

Hi Mr. bennettj,

Nice work so far. It's good to hear another classic GS being saved. Which bike do you have?

It sounds like your carbs may not be totally clean, and/or the valves need adjustment. Many more tips here in my "welcome thang"...

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Pacman]

You didn't mention whether you synch'ed the carbs. You have one, or more, of three things wrong. The low speed jets still gunked up, carbs out of synch and/or valves out of spec.

Adjust the valves (needed anyway), then pull the carbs and blow carb cleaner through the low speed passages and replace the low speed fuel jet (pilot jet) and when you put them back on the bike make sure they are synch'ed. This should solve the problem.

Chris

[bennettj]

Missing Info - 1983 GS650G

Thanks for the feedback. I have made extensive use of the sight and BikeCliff website with work done thus far. Great to have these resources available. I am confident that carbs are cleaned and rebuilt (with kit) properly. Admittedly, I was psyched to ride and have not synch'ed the carbs nor adjusted the valves. Guess I know what I'll be doing this afternoon.

[Matchless]

Just a quick question when the bike is started from cold and idling, do all the header pipes heat up the same or do you have a cold pipe or two?

[Dave8338]

No mention of the air box and its' related filter...

[almarconi]

No mention of the air box and its' related filter...

No mention of what bike he's talking about either. VM and CV carbs are not adjusted the same. I'm sure if you turn the fuel screws on VM carbs out 3-1/2 turns its going to run like crap, especially if the air screws are closed.

[bennettj]

new air filter and plugs. The bike is a 1983 GS50G. Number three cycle exhaust pipe is cold until running approx 5 minutes.

[Matchless]

new air filter and plugs. The bike is a 1983 GS50G. Number three cycle exhaust pipe is cold until running approx 5 minutes.

I think you may have your problem identified, or at least one of your problems, as you are running on 3 cylinders. I would first look at #3 carb.

For peace of mind, you may want to check your #3 plug and HT lead and connector.

See if the #3 bowl is full before starting and also check the idle (pilot) circuit.
When cleaning did you probe the extra 3 holes behind the butterfly and are you sure the idle jet is properly clean, probed, dipped, squirted, blown and squirted again in that order? - this then also goes for the complete idle mixture path.
I can promise you that many of the members have initially cleaned their carbs a second time after thinking they have done it correctly the first time and don't ask me how I know this!
Good luck

[chef1366]

A 50cc shafty!

Cool!!!