Topic: 79cb650 bogs and sputter?

[79custom]

Hello new here
Hope I can get some help I here, my 79 cb650 starts good runs well in low and high rpm but once it's warmed up like after leaving a highway for a few miles and u slow down to an off ramp or to a stop sign it Boggs and sputters like it doesn't want to move and has a hard time idling, once I get it down the road and give it the gass it sounds terrible like it's bogging down and not wanting to catch then it catches and pulls hard and is back to normal for a while.

I checked the carbs they are clean, jets slow and main are clean, the bike worked great until a few weeks ago, I replaced the plugs, and checked them they are golden brown on the tip but black on the threads, the bike also backfires when you decelerate from higher speeds. It backfires out the pipes but I think it also fires into the carbs as I noticed black marks on the carb cylinders that hold your needle.

Any ideas as to what the  heck is going on, it's jetting is stock same as the air box, the only thing I can think of is it has a few wholes where the exhaust/header meet.

Could it just be running lean? Please help???

[79custom]

Also just took it for a short ride it bogged after riding it for 10 min I pulled over while it was doing it and it sounded like it just wasn't firing on all cylinders, I revved it a couple times pulled the choke out let the engine rev up for a second then pushed it back in turned the bike off and back on and the problem was gone, then rode home for the rest of the ride about 20 more minuets and it didn't do it again. It's like its intermittent and very annoying.

Any ideas, it runs great on highways or at constant speeds for long periods just gets really bad when u slow down to stop signs. Just don't want to be damaging the bike.

[harisuluv]

Well, no one is going to be able to tell you much without specifics about your setup, specifically air and exhaust.

That being said, popping on deceleration is a sign of leanness.  If you are ok at higher speeds that would indicate that throttle range (main jet) is fine and you have issues with lower speed circuits, i.e. slow/idle jet and mixture screw. 

From the way you described your verification of carbs being clean, it doesn't really sound very thorough, no offense.  Those slow jets are also pressed in so unless you took them out which is not usually what people do before they know about them, you're going to have to do that.

[79custom]

My setup is stock jets stock air box and stock exhaust the only thing not stock on the bike is the handlebars lol. I disassembled the carbs to clean them down to taking out everything but the slow jets. Since I didnt want to rip them out until I do the engine rebuild this winter I just ran some carb cleaner and compressed air through them after I let the carbs sit in a sonic cleaner for a while so besides tanking them out they are as clean as im getting them until i re jet them.

I'm doing a rebuild over the winter of the carbs and top end of the engine but thats not for a month so in tye meantime id like to figure this out.

[harisuluv]

I don't know what to tell you then, if you insist on not addressing the slow jets which are the most likely culprit I can't recommend another course of action.

An ultrasonic cleaner isn't magic, and often is ineffective on varnish unless you use some special solvents which most people do not have commercial grade solvents.  In order to properly clean them they need to be pulled and cleaned until you can physically see light through them unobstructed.  You also have to do this with proper gauge wire so you don't damage the jet.

[79custom]

I will definitely pull thwm tonight and have a look see thanks

[mono]

Coils?

[my79650]

Tru using the tie for garbage bags; strip the covering off. It is strong enough to clean the slow jet holes out but not that strong to make them bigger. Works good as that what i use to clean mine.