hard starting

Post Reply
cbx104
New Member & Happy To Be Here
New Member & Happy To Be Here
Posts: 6
Joined: Sun Jul 30, 2023 11:44 am
Location: Gravenhurst Ontario Canada
Location: Gravenhurst Ontario Canada

hard starting

Post by cbx104 »

Have a 79 cbx that I picked up last summer Has 48000 k Bike needs a lot of cranking over before it will start To avoid burning out starter I only do short attempts of a few seconds It always starts after several minutes of this and runs a bit rough until warmed up After that it runs fine Any ideas on what could be the issue?

Dynamohum
Power Poster
Power Poster
Posts: 269
Joined: Sat Oct 28, 2017 3:24 am
Location: Coarsegold, CA
Location: Coarsegold, CA

Re: hard starting

Post by Dynamohum »

It’s almost always the carbs, old sticky fuel running thru the fuel lines which is typically the result of neglect, like starting it twice a year and storing it without a full fuel tank. They could be way out of synch too. These six carb wonders need to be started and ridden frequently to prevent this issue. Until that’s addressed, make sure to use the proper starting procedure. Clean tank? Fresh gas? Gas on, few seconds later twist the throttle a couple times and then open the choke and hit the starter. When it begins to catch give it a lil throttle. Keep it running for a minute on full choke and then ease off the choke. If the idle is set right, in the neighborhood of 900/1000/1100 rpms and the carbs aren’t thoroughly trashed, it should run ok. If not, the carbs need work as does the fuel system, more than likely. Good luck!
Last edited by Dynamohum on Wed Sep 11, 2024 1:06 pm, edited 1 time in total.

Rick Pope
ICOA Rally Director
ICOA Rally Director
Posts: 2311
Joined: Wed Sep 03, 2003 3:16 pm
Location: Lawrencburg, IN
Location: Lawrenceburg, Indiana

Re: hard starting

Post by Rick Pope »

Are you draining your float bowls? When you shut down the bike, fuel remaining in the bowls is subject to the heat of the cooling bike, which cooks off the lighter components, the part of the fuel that's easier to light.

Drain the carbs, then next time you ride, turn on the fuel a minute before attempting to start it.
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

CBX-tras
ICOA Member
ICOA Member
Posts: 460
Joined: Tue Feb 16, 2010 1:29 pm
Location: Clinton Twp, Michigan
Location: Clinton Twp., Michigan, USA

Re: hard starting

Post by CBX-tras »

Extracting and enlarging the idle jets from #35 to #38 with help with hard starting and overall performance. Proper float height, good ignition (coils, plugs, wires), battery condition, will also play into it.
If you don't know when the last time the carbs were serviced and the connector boots replaced, you are due, sir.

On another subject, the food at Well Fed in Gravenhurst, is some of the best. The business was founded by a friend of mine and the new owners are keeping the same quality that Annette had in the past. If you haven't been there, try them.

User avatar
Jeff Bennetts
Posting God
Posting God
Posts: 2485
Joined: Wed Mar 05, 2003 8:38 am
Location: Ohio, USA
Location: Ohio, USA

Re: hard starting

Post by Jeff Bennetts »

CBX-tras wrote:
Wed Sep 11, 2024 8:19 am

On another subject, the food at Well Fed in Gravenhurst, is some of the best. The business was founded by a friend of mine and the new owners are keeping the same quality that Annette had in the past. If you haven't been there, try them.
You just never know what knowledge will be dropped on this forum, you can read for days about carbs, charging sys and the rest but a good restaurant recommendation is priceless!

cbx104
New Member & Happy To Be Here
New Member & Happy To Be Here
Posts: 6
Joined: Sun Jul 30, 2023 11:44 am
Location: Gravenhurst Ontario Canada
Location: Gravenhurst Ontario Canada

Re: hard starting

Post by cbx104 »

No I don't drain the carbs after every ride I did last fall before storage The previous owner had some carb work done just before I got the bike including new connector boots Not sure what else was done The enlarge idle jet idea sounds interesting Not sure how to extract but will look into that And yes the recommendation for Well Fed is spot on! Though I haven't been there since new owners took over Will have to do so!

Rick Pope
ICOA Rally Director
ICOA Rally Director
Posts: 2311
Joined: Wed Sep 03, 2003 3:16 pm
Location: Lawrencburg, IN
Location: Lawrenceburg, Indiana

Re: hard starting

Post by Rick Pope »

Draining the carbs is a cheap and easy thing to try. Trial and error will let you find where to turn off the fuel as you return home so that the bike is sputtering into your driveway. Flip on the choke to help get the last of the gas out.

And I agree with Jeff, restaurant recommendations are always good. Perhaps a new thread should be started on that one.
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

CBX-tras
ICOA Member
ICOA Member
Posts: 460
Joined: Tue Feb 16, 2010 1:29 pm
Location: Clinton Twp, Michigan
Location: Clinton Twp., Michigan, USA

Re: hard starting

Post by CBX-tras »

Pilot jet extraction tool and a short, how-to video:

https://www.kmcarburetor.com/products/h ... moval-tool

User avatar
80 cbx dude #6216
ICOA Member
ICOA Member
Posts: 290
Joined: Wed Jul 29, 2009 5:19 pm
Location: Fort Lonesome, Florida,USA
Location: Florida

Re: hard starting

Post by 80 cbx dude #6216 »

Another thought is to make sure your fast idle cam is raising the throttle plates a slight amount for a faster idle when the choke is applied. There is a specification in the Work shop manual. Mine was out of specs when I received my CBX. - Mike

Post Reply

Return to “CARBS: Cleaning, Rebuilding, Swaps, Aftermarket, Tuning, Syncing, and More”