The International CBX Owners Association

I was out scaring myself on my CBX on the weekend when it suddenly started breaking up and running rough. I was at about 7 grand in 4th when it coughed, cleared itself on the way up but continued to run rough.
After letting it cool off, i fired it up and now it will not idle or run smoothly unless it is way up in the rev range. It is also running hot.
All six cylinders are running. It also has a Dyna ignition, coils and Taylor wires.
Does it sound like the igniton advance might be staying in full advance?
Maybe in the retard position?
I have not seen/heard of this being a problem in any of the old posts.
Any thoughts would be greatlyl appreciated.

Steve,

From your description, I would be thinking along the same lines. It sounds like timing/advancer problem.

It seems to make sense to me Chris. It happened all at once and to all six cylinders. I have an old timing light some where in the back of the garage.
Finding it might be the hardest part of this problem.
Dyna products seem to bulletproof, hopefully i will be able to rule out anything in that direction.
I will be fighting with this on the weekend.

In "theoretical" order of probability.......

Mechanical advancer, stuck or fragged.
Bad (intermittent) ground connection.
Ignition timing "slipped".
Cam timing "slipped"

Again, thanks for the input guys.

You're getting good fuel flow from the tank? Exhaust pipe baffle come apart, blocking exhaust?
I'm not familiar with'Dyna ignition' only their coils and wires. I take it the ignition is a different advancer? Or control module?

Hey bobber.
Fuel flow was my first guess the way the bike reacted. A check of the inline filter provided full flow. Back pressure from the exhaust is fine.
The Dyna unit is indeed a control module. They send you a new rotor/ contact point? and a new module/plate.
I will certainly post any solutions when i get at it on the weekend.

I have a Dyna ignition and it uses the stock mechanical advancer. On mine I replaced the rotor on the advancer with the dyna rotor. The dyna rotor has a magnet in it. The advancer can rust and bind.

Good news, bad news.
Good news, the ignition advance and the Dyna ignition are both working properly. The timing was spot on and the advance was working and returning.
Bad news, i think i am heading to carb school.
I put new plugs in the bike at the first sign of trouble and they are now wet and black. The air filter was soaked, it is running very rich. New plugs and a clean air filter and i get it is now running lean. The plugs are scary white. The bike is still running rough starting at about 3000 revs.
It just seems odd to me that the symptoms happened so suddenly and to all six cylinders for it to be carb related.
Round 2 is about to begin.

steve murdoch icoa #5322 wrote:Good news, bad news.
Good news, the ignition advance and the Dyna ignition are both working properly. The timing was spot on and the advance was working and returning.
Bad news, i think i am heading to carb school.
I put new plugs in the bike at the first sign of trouble and they are now wet and black. The air filter was soaked, it is running very rich. New plugs and a clean air filter and i get it is now running lean. The plugs are scary white. The bike is still running rough starting at about 3000 revs.
It just seems odd to me that the symptoms happened so suddenly and to all six cylinders for it to be carb related.
Round 2 is about to begin.

That is a puzzle Steve.

Could it be bad fuel? Fuel starved now for some reason such as clogged fuel filter?

I had so many similar puzzles getting my '79 to run that I thought it needed an exorcism rather than a mechanic.

steve murdoch icoa #5322 wrote: I put new plugs in the bike at the first sign of trouble and they are now wet and black. The air filter was soaked, it is running very rich. New plugs and a clean air filter and i get it is now running lean. The plugs are scary white.

Steve, I must admit I don't understand this ???? When you say the air filter was soaked, do you mean with fuel ???? Are the new plugs the same heat range as those that were wet & black ????

Sorry guys about my lame descriptions.
As of now i have ruled out any igniton problems.
The wet paper air filter was from being SOAKED in K&N filter treatment. The bike has 6-6 Pipemasters and the previous owner was running the bike with no lid on the airbox and a 1" hole in the bottom front corners of the airbox.
When the rough running first occured the Irridium plugs looked to be very dirty and covered in a hard glazed coating. I put new NGK DR8ES-L plugs in the bike and the rough running continued with the plugs being very black and sooty. I cleaned the air filter, put a lid on the airbox, put another new set of NGK plugs in and the rough running continues only the plugs are now white.
The rough running now starts at 2800 rpm and with a gradual throttle will clear out at about 6000 rpm.
From what i have found in the search forums it sounds like shimming the needles is the next logical step. I will also go back to a stock airbox and filter.
Ding. Round 3.

Steve, Just for kicks & giggles, spray some starting fluid around the carb connections & see if the revs change.....