Engine turns - no pop

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

oregonandy
Posts: 37
Joined: Sat Feb 06, 2010 12:06 am

Engine turns - no pop

Postby oregonandy » Sun Jul 10, 2016 3:52 pm

Hi, all. . . after many weeks of on-again/off-again hassling with the t-joints on my carbs, finally they're back on with no leaks. I checked the bowls, they have fuel. The battery is only about a year old and it seems to turn over just fine but not a single pop. I thought maybe it wasn't even getting a spark so I stuck a screwdriver in one of the plug boots and saw that it sparks from the screw driver to the engine. I'm not sure what a strong a spark would look like but I'd call this one.. weak? Just sort of a little ticking sound as it arcs, almost like a gas stove lighter. Is that about normal? I tried spraying carb cleaner on the plug and in the chamber but after running the starter - with no firing - the plug is still wet with the carb cleaner.

It's been a year or so since this has ran but was running fine then. I'm stumped why I don't even get a single pop. It's almost as if I'm starting it with the Run switch in the OFF position - but as I said, I do get a spark of some sort.

Any suggestions on next steps for me would be greatly appreciated!

Andy

cruiserlover
Posts: 87
Joined: Tue May 17, 2016 9:56 am

Re: Engine turns - no pop

Postby cruiserlover » Sun Jul 10, 2016 11:00 pm

many experts here, I am not one.But you may have identified your problem.The run switch may be permananetly engaged.Or the ignition switch is messed up.Taking the handlebar controls apart is gone over with a video on this site.I saw it once.
Owner of 79 cb650.Non running.Current bike 2004 heritage softail. Denton Texas

oregonandy
Posts: 37
Joined: Sat Feb 06, 2010 12:06 am

Re: Engine turns - no pop

Postby oregonandy » Sun Jul 10, 2016 11:27 pm

Thanks, that's what I thought initially. In fact, while I was loosening the throttle cables I must have disconnected the switch that goes to the brake lever. Both connectors were undone so I thought that may have been the cause (I figured that was just the brake light switch but wasn't sure). But after I put the screw driver in there and saw the spark, I figured that ruled out the run switch possibility (unless the run switch somehow disengages the coil but not the spark).

cruiserlover
Posts: 87
Joined: Tue May 17, 2016 9:56 am

Re: Engine turns - no pop

Postby cruiserlover » Mon Jul 11, 2016 7:23 am

maybe pm some of the guys on the internal link section here.There are threads pertinent to electrical for these bikes.
Owner of 79 cb650.Non running.Current bike 2004 heritage softail. Denton Texas

User avatar
tario
Posts: 166
Joined: Sat Mar 07, 2015 2:26 pm

Re: Engine turns - no pop

Postby tario » Tue Jul 12, 2016 8:18 pm

You could try to jump it off a car battery to see if it just needs more juice. (car not running) Other than that cleaning out your connectors can help a lot. I put dielectric grease on my connectors to try to keep a good connection.

If it isn't firing and it has good compression then you either have no spark, no gas in the cylinder, or it's flooded. (Speaking of flooded if you soaked your spark plugs with anything they might not fire.)
1979 cb650
1980 cb650

User avatar
Volker_P
Posts: 5508
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Engine turns - no pop

Postby Volker_P » Wed Jul 13, 2016 4:06 am

First check this:
Plug cables from left coil go to cylinders 1+4, from right coil to 2+3. :wink:

To hear a ticking sound with the spark is all right.

Throttle needs to be almost closed: Turn out the black manual idle knob out until it looses contact to the lever.
Then turn it back until contact to the lever and then another 1/2 to 3/4 turns in.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum


Return to “Technical Discussion”

Who is online

Users browsing this forum: No registered users and 52 guests