idle jet differences , 069's

[fogrider]

I've seen a few references to it on these forums which makes it appear as a known issue.

It does not bog down when it gets hot, it bogs badly from cold , choke eases it ( then gets too rich and I have to take choke off so it bogs again. ). Perhaps I explained that badly.

Get above 1/3 throttle even when cold and it flies. Runs much better once warmed through , but it takes a few miles. All brass wear is good, new float valves and main jets plus all O rings. No leaks. Fuel levels proved correct.

I've decide to fit my lambda sensor kit tomorrow, just after the 4 into 1 and see what the reader says , that should be interesting.

[Bryanj]

There is smething ese wrong with it somewhere as that is not ormal and carb slides dont alter

[deltarider]

Best advice I can give, is to start from as stock as possible. Consulting Honda docs can be a great help, but... not when there is an error. You may read about an error in the page that deals with the initial carb set up. A German discovered this not that long ago. The correction he made, has already helped others. http://forums.sohc4.net/index.php/topic,184299.msg2133957.html#msg2133957 Not saying it is the cause, but the position of the slides - and thus the cut outs - is involved, so it wouldn't hurt checking you have the correct initial set up. It's quickly done.
A further addition. Don't make the mistake in trying to achieve a highest rpm* at idle by turning the air screws out. It is possible and the engine will pur like a kitten, but you will have a rotten acceleration. These CB500/550s need an idle mixture that is on the rich side, which - strange as it may sound - could imply having the slides a bit higher. 
*This may be the correct procedure for other carbs. Ours are very basic and lack acceleration jets.

[fogrider]

As far as I know, it is all standard and the carb settings right, including the 49mm thing. Idle screws down to 1 and 1/4  turns out.
 I only bought it last October and the wiring mess was the priority and this year I set  to re-painting  the tank and side panels
 so hardly ridden 'till recently. When I stripped the carbs to check the internals  it seemed strange that the carb slides  looked as new. It was off the road a while after the last owner died and  someone since has re-built the wheels and I wonder if it's also had new slides - the wrong ones ?
It's remains a mystery, whatever I've checked or done.
Before I go overboard with slide mods, I checked the voltage to the coils. It revs free in neutral but bogs (when cold) on the road. That is typical of ignition faults and sure enough, there is a loss of 1 volt with the ignition on (but with the coils disconnected). No lights on. Some drain somewhere ?
It's still got the old type of reg and rec , I might try new , Podtronics OK ?

[deltarider]

As far as I know, it is all standard and the carb settings right, including the 49mm thing. Idle screws down to 1 and 1/4  turns out.

Try 1¹/₂, 1³/₄ and 2 turns out and see what it does.

...  it seemed strange that the carb slides  looked as new...

So do mine and they are 45 years old.

I checked the voltage to the coils. It revs free in neutral but bogs (when cold) on the road. That is typical of ignition faults

Really?

... and sure enough, there is a loss of 1 volt with the ignition on (but with the coils disconnected).

I'm afraid I can't follow you here. If you mean onboard voltage drops 1V when - with IGN key ON - kill switch is switched from OFF to RUN, that's not abnormal. 

It's still got the old type of reg and rec

Good, keep them, they rarely fail. Recently on the German site someone proved his stock regulator is actually better than electronic as it compensates somewhat for temperature, which none of the electronic ones do, not as far I know.

, I might try new , Podtronics OK ?

Don't.

[fogrider]

Opening the air screws makes it worse. It starts to  spit back in the air box even worse..  I started to suspect the cam timing in case  someone had replaced the chain and it was slightly out.  It's absolutely bang on.
It still all points to weakness and after marking the throttle grip, the bad spot is well before 1/4 open. It's a real flier once it's above 3000 rpm ( for 50bhp anyway ) and past 1/3 rd throttle, nothing wrong with the engine. No backfiring on the over-run.

Having another scan of previous similar posts, someone in New York (I think)   -Nordstudio- had exactly the same problem in 2009. The thread stops before any cure is stated. Typical.
My son thinks it's the Jama silencer, can't see that, it goes too well. Unless others have had issues with a Jama ?
Sick of it for now, it's going under a sheet in the corner and the T150 is coming out for some fun.

[K2-K6]

I view it that there's no particular ideal for airscrew setting,  wind it down to only 1/2 turn out and it well tell you something at least.

If it covers it off then that's really telling you that it could benefit from one step up in idle jet size with the screws in more conventional range.

[fogrider]

Thanks K2-K6, I have tried all ways with the idle screws. When screwing in, at less than 3/4 turn out it starts to kill the engine and I have to turn back out to at least 1.  It won't wear 1/2 a turn at all.   It ticks over  quite well at 1 and a  1/2 turns out, at 1 and a 1/4, when fully warm, it's almost sorted, just some hesitation bottom end which is a pratt in traffic.

That reminds me of a classic Citroen dealer  in Germany I buy parts off. In their very elaborate parts manual, ( English translation ), there is a description of "the enjoyment the boss gets out of screwing." I rang him and asked what it meant. When he said working with the tools and the fasteners, I explained what screwing meant in the UK.

It went quiet for a bit, then laughter.

I'll sort it, eventually, it goes too well to be anything expensive.

[K2-K6]

If you want to try something that runs against conventional thinking, you can use resistor spark plugs and plug caps together and gap the plugs at the absolute minimum of specification in the manual.

I'm intrigued as to this and if it makes a difference both positive or negative on other's engines. My experience is that it's effective with leaner mixtures and helps to avoid it going toward a flat spot without forcing mixture rich to achieve it.

[fogrider]

I get the idea, but when I bought the T150 it was a git to kick off. I found it had resistor plugs and 10k ohm plug caps.
I got 5k ohm  caps and non resistor plugs and it became easy to start.  ( it had copper leads already ).

I've tried the plug gaps at 30 thou and down to 24 thou. Could'nt tell any difference although the sparks do look poor, pinky/purple not blue, but it pulls hard, even in top, so my thought a weak spark was letting it down did'nt pan out.

I've spotted an issue with the timing marks I'm going to investigate. It's possible timing errors may be upsetting carb synch and settings.

It came with a simple foam liner instead of a paper element filter, I see some people run pods without a problem but it might be a small part of a joint enterprise in upsetting the running.

Work in progress.

[Bryanj]

Pods are always a problem and the "simple" foam filter may just be altering the airflow enough to upset the running

[fogrider]

You're right, I'm just checking and eliminating what I suspect and ensuring all is correct. There had been a lot of poor work on it, neglect, bodgery even ,so I don't know what's been done until I dig into it. Lots of little things together can add up. Making the slides slightly richer is a last resort, as you say, it should'nt need it but if that's what it takes......I'll try it even if it's just an experiment. Last resort.
When I finally cure it, it will be the most comprehensively  serviced CB550 on the road !

Had a look another look at the 56mm/ 49mm thing while the tank was off (again). I had set mine at 56 whilst the carbs were off , it's not critical, simply puts the cable crank in the right field, hence the 3mm allowance. The German guy simply measures it from  more obvious points. The measurement is point to point too, I notice someone on here was measuring  it 38 mm, but was being mislead by the lines added to the photo. It was probably right point to point !

[K2-K6]

Presumably T150 is a Trident? Can see your point there regarding mixture. These 550 are probably exactly the opposit and bang on the money for AFR with any error likely to be toward lean if any compromise is present.  Generally extremely accurate for fuelling and run well through their rev range.

Agree with Bryan's view regarding foam filter, they are certainly sensitive to any shift within intake system and many struggle when using pods.

Interestingly,  pods in my view seem to need different cut slides,  which ties with your perception now. Probably a good move to asses with original type air filter to see what you get.

[ST1100]

Pods are always a problem and the "simple" foam filter may just be altering the airflow enough to upset the running

Couldn't agree more... (had a recent episode with a CB600F PC36 which was garaged for 3 years and wouldn't fire "...just needs carbs cleaned..."; yeah... all cleaned and bench synced it fired up nicely, but bogged on throttle... sports-filter out, OEM paper element in, and what you know, reving promptly and smooth...)

OEM setup seems the best, as it's just working under all given conditions...

[fogrider]

Air filter element and 4 spark plugs being ordered tomorrow. The plugs look OK, but who knows how old they are, won't hurt to have a spare set if they make no difference.
Made some experimental changes to the ignition set-up , had a ride around , definitely improved and even my non technic wife said, on return, "that sounded way better".

Hopefully, an air filter may just make the final difference. Should have spotted it was'nt a pleated paper one sooner.