Help needed. Do I have a carb problem ?

Post Reply
JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

Bloody rain stopped play lol.
So decided to try a coil swap, but the coil doesn`t work so forget that one. But someone I know might have a couple of spare Kawasaki coils for me to try.
On starting she fired first touch of the button from cold, but with the usual audible misfire while warming up.
Hmmmmm, I thought as I decided to switch off.
Out with my spray nozzle and squirted some water onto the down pipes. No1 was not hot, only warm.
There is a new plug in there and new cap and lead.
So a possible faulty coil or a bunged up carb ?
As I type this the sun starts coming out again, but I`m now away out of town to visit my daughter. Typical.


Mike

User avatar
wyly
ICOA Member
ICOA Member
Posts: 1727
Joined: Tue Oct 30, 2007 4:20 pm
Location: calgary alberta canada
Location: Calgary Canada

Re: Help needed. Do I have a carb problem ?

Post by wyly »

maybe the coil wire to number one isn't seated but otherwise I'd guess it's carb #1... if the coil were faulty wouldn’t you have two cold pipes, one and six?
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

wyly wrote:maybe the coil wire to number one isn't seated but otherwise I'd guess it's carb #1... if the coil were faulty wouldn’t you have two cold pipes, one and six?
That's what I`m thinking Wyly.
Something bothering me though. Does anyone know how these coils are made up ?
I know they fire together creating a wasted spark.
But the earth connection to the mounting bracket at each end of the coil. Is it one single connection ? Or is there actually two circuits inside the coil requiring 2 earths ?
If it is the latter then it could be a bad earth at one end causing one side to fire okay and one to misfire.
I think over the weekend I am going to strip the coils out and clean the mounting bracket and all connections and retry it.
Tonight I have been loaned a couple of Kawasaki coils to try. They are a little shorter than the Honda coils but they should suffice to either confirm or deny a problem with the originals.
Because I couldn`t get out today I`ve not had a chance to run the bike with the carb cleaner, so hopefully I`ll get that done tomorrow.

Mike

User avatar
wyly
ICOA Member
ICOA Member
Posts: 1727
Joined: Tue Oct 30, 2007 4:20 pm
Location: calgary alberta canada
Location: Calgary Canada

Re: Help needed. Do I have a carb problem ?

Post by wyly »

I would think Phil, Dave , EMS or Herdy Gerdy could give you a definitive answer on the coil internals...certainly easier to check out the coils than the carbs :D ...my money is still on it being a carb problem, you said that there are certain points in the rpm range where there are no problems , if it was the coil I'd think the problem would be right through the rpm range?? :think: but I don't have the expertise of the other forum members I could easily be wrong :roll: ...

when I had carb issues it would be worse in certain sections of the rpm range than other sections...the last time it was lurching/bucking under 2K and a terrible clutch rattle... the idle setting on one carb was the problem even though they were all turned out exactly 3/4 turn, pot number three wasn't happy so carb three needed to be tweaked ...
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

I think Wyly that we have all been spoilt by the new bikes. They do everything automatically and rarely fail if truth be told. When we go back to old technology like the CBX has we end up stumped. Well that's my excuse for me lol.
Years ago I used to race and tuned my own engines. But then I moved on with the times and got sanitized with newer Hondas and latterly Triumphs. my other bike is a Rocket 3.
But the fact is that if we don`t keep our hand in you forget. And this is where forums like this can not be lost with the wealth of knowledge in them and the expertise of the people who DID keep their hand in.
I had my old CBX stripped naked for a full rebuild including new shells and chains in the engine. I also did the carbs and balanced them without gauges, and it ran like a watch. But 30 years on .........................................
I`m back at the drawing board lol.
That misfire I found in No1 cylinder has me leaning strongly to a fault in that carb. But tonight I couldn`t replicate that problem grrrrrrrrrr.
Tomorrow is another day however. I want to run it with the carb cleaner. If no improvements I`m going to haul out the coils for a clean up.
If that fails it will be carb strip time.

Mike

daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4737
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: Help needed. Do I have a carb problem ?

Post by daves79x »

Again, and again - it's the carbs!

Dave

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

It`s Okay Dave, I`m believing you.
I had to rule out other things first because that's just how I work. Not once have I doubted anything that anyone has told me. But in my own mind I had to rule out the electrical side. And I think I have now done that.
Today I went for a run to get some more cleaner through the system but no noticeable difference, so I`m thinking of pulling the carbs tomorrow for a peek inside.
While out I paid closer attention to whats happening, so feel free to step in and offer your thoughts.
I thought that it might be better to test things in top gear and see how it performed in that one gear instead of just blasting through the gears and maybe getting different results.
To sum it all up from starting the engine.
The engine fires first turn so no bother there. It needs choke to start from cold but there is no fast tickover. I have to use the throttle to keep revs up to warm the engine.
When the engine is warm it revs up easily if I blip the throttle to about 3K rpm. Tick over is a solid and steady 1000 rpm. If I rev to 4K rpm the misfire is noticeable, although slight.
On the road I can bring the engine down to 1800 rpm in top gear and on opening the throttle get a slight hiccup and then it pulls cleanly. (This was all done while carrying a passenger).
On nearing 4500 rpm (still in top) the misfire starts to make its presence known, and by 5K rpm I hit the wall.
If I roll off the throttle ever so slightly the misfire goes and the engine purrs.
This leads me to think the slow jets are clear and there is a problem with the primary jets.
I did this several times and always with the same result.
Next I gassed it up full on from 1st gear.
Short shifted into 2nd at half revs then held it going. I hit the wall at 5K and kept going till I broke through and from about 7500 rpm the power kicked in and she went for the red line.
Changing gears at the red line she was flying. The misfire was still there but not nearly as noticeable.
Now this is where I need the knowledgeable people to correct me if I am wrong.
The slow jets are working okay. The primary jets are faulty. The main jets kick in at the higher revs and help to override (not cure) the fault with the primary jets.
So I`m now looking at checking all the jet sizes and making sure they are all clean (particularly the primary jets) including relevant airways etc.
Float levels will be checked and reset if needed. Air screws set at 2 turns out ? or will they be fine on 1 1/2 turns ?
Thoughts please ?
When I do open the carbs I will take photos and if anything is relevant I will post them to share anything I find.


Mike

User avatar
wyly
ICOA Member
ICOA Member
Posts: 1727
Joined: Tue Oct 30, 2007 4:20 pm
Location: calgary alberta canada
Location: Calgary Canada

Re: Help needed. Do I have a carb problem ?

Post by wyly »

JustMike wrote: I had to rule out other things first because that's just how I work. Not once have I doubted anything that anyone has told me. But in my own mind I had to rule out the electrical side. And I think I have now done that.
Today I went for a run to get some more cleaner through the system but no noticeable difference, so I`m thinking of pulling the carbs tomorrow for a peek inside.
that's how try to approach it too I'm not mechanically experienced like most here...I try eliminate most small things that could be wrong even though all the symptoms are indicating it's time to tilt the engine, it's not a fun or small job...

what did you use for carb cleaner? I use Seafoam, it works even when the bike is just sitting in the garage...last time I used it I was into my 2nd tank of fuel over four days before the carb problem cleared up...but like Dave said I think in this case you'll be pulling the carbs...
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

Wyly, I forget the name of the first cleaner I tried, but it did help stabilise the tickover and low end throttle response.
The one I have just tried is https://products.liqui-moly.com/additiv ... ooter.html
But the question with these cleaners is, how long before they do anything, if ever.
I have sent for some carb cleaner in preparation for me stripping the carbs.
Because they have already been fully stripped previously I`ll not take them right down, but I`ll concentrate on checking all the jets and cleaning out the passages etc for now.


Mike

User avatar
wyly
ICOA Member
ICOA Member
Posts: 1727
Joined: Tue Oct 30, 2007 4:20 pm
Location: calgary alberta canada
Location: Calgary Canada

Re: Help needed. Do I have a carb problem ?

Post by wyly »

you have to ask the same question of whoever did the initial cleaning too...I had my carbs cleaned by a "professional" and he did a shit job, he gave it the sonic bath or whatever and called it done...I ended up pulling the carbs and found many of the tiny orifices and the air cut valve (which had never been opened) were plugged solid... I went through an entire can of carb cleaner and 3-4 hours cleaning the crud out...

I'm always dubious when I hear manufacturers hype their products cleaning abilities but I heard of Sea Foam from other bikers and it worked as they said it would...it cleared up the stumbling my carbs were experiencing...
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

Funny how you say you went through a can of cleaner Wyly. I ordered 4 cans lol.
Made up a big tray out of plywood today to lay the carbs out on. I put sides on to stop anything rolling off and getting lost.
Just need to get my finger out and get started now.
I spent the day looking for info on rebuilding the wheels. It looks like I have a few loose rivets so thinking about stripping down and replacing the rivets with bolts instead.


Mike

User avatar
wyly
ICOA Member
ICOA Member
Posts: 1727
Joined: Tue Oct 30, 2007 4:20 pm
Location: calgary alberta canada
Location: Calgary Canada

Re: Help needed. Do I have a carb problem ?

Post by wyly »

There’s a 3” gold comstar rear boomer on eBay uk maybe you want to look into that before rebuilding your wheels, only need to find a front boomer and you’re golden :D

I’d buy it myself but shipping cost is too much to Canada
CBX a work in progress, still improving...GS1150EFE completed and awaiting modifications.....RD350, remnants in boxes scattered throughout the garage

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

Yes I`ve found a few wheels. And thinking about getting some. only then would I play around with stripping my current ones.

Mike

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: Help needed. Do I have a carb problem ?

Post by EMS »

Just my opinion: You will NOT be able to completely clean CBX carbs with just any fluid or even super sonic process. You will have to use mechanical methods also.

JustMike
Forum Regular
Forum Regular
Posts: 65
Joined: Fri Jul 20, 2018 7:14 pm
Location: Scotland
Location: Scotland

Re: Help needed. Do I have a carb problem ?

Post by JustMike »

I hear you EMS.
I`m going in there expecting to become a mole and burrowing through every cavity.
Also I have been gathering as much information as possible from the internet about the various problems people have encountered and how they fixed them.
Unless I`m lucky and the problem is in my face when I open them up I`m expecting to be spending a few days going through them with a fine tooth comb.


Mike

Post Reply

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