Wont exceed 4,500 rpm then stalls and wont restart - on route to MOT

[totty]

I stripped the carbs, found a blocked main on number 2, a blocked pilot on number 4 and float heights a bit out. Also fitted a fuel filter, checked the timing with a strobe and fitted a working oil pressure switch.
It ran like crap at first then sorted itself out and was fine for an hour but lost all power just as I was arriving home - This was after sitting in a traffic queue for some time.

[SteveD CB500K0]

The loss of power may have been caused by overheating (happened on my 550K3 many years ago queuing to get into Silverstone).

Keep an eye on the fuel filter - I don't like them and believe that Honda would have fitted one if it was really needed. My K2 had those little in-line filters (two) but they got clogged easily and then the engine stopped.
(Maybe you will say that that crap would have gone into the carbs and the engine would have stopped anyway...)

[totty]

I'm hoping that's all it was, the queue was quite long, I'll see what it's like when I next ride it.

The filters easier to clean than the carbs :-)

[UK Pete]

This seems to be a very annoying time consuming problem for you, i do hope you get it fixed soon as these problems can really put you off a bike, i had four months where i could not solve a problem with one of my kawasaki's it turned out to be an intermittent problem with the electronic ignition, it drove me round the bend, and i ended up hating the bike for quite a while
Pete

[totty]

My patience is starting to wear a bit thin with it.
Once it's sorted it's going to take me a while to build up enough confidence in it to go any distance which is a shame as this was supposed to be my distance bike with the monkeybike staying in use for local rides.

[UK Pete]

Do you ride the monkey bike much?  I have a Honda dax which i dont really ride much, i bought a chinese 125 engine for it as well as a loom and all parts needed to turn the bike in to a 125 12 volt, but i lost interest and have not touched it in two years, i will keep it as they rise in value all the time, maybee some time i will do the engine swap just to see how it goes
As for your bike with the problems, take your time and do everthing as properly and cleanly as you can so you dont have to keep re-doing the same thing, sooner or later you will hit the jack pot and all will be good.
Pete

[totty]

I use it to get to work when the weather's nice and also do one or two of the many organised runs.
Mines just a Chinese z50 copy running a 120 engine.

[matthewmosse]

Checked compression? My first 550k3 wouldn't behave at all if hot, ran too fast or cut out, down on power and overheating. Starting from hot was inpossible (also leaked oil like a sieve) Turned out the top piston ring was MIA on all 4 pistons, tops of the pistons were cream crackerd. half a ring was found in sump, no idea where the rest of them went (suspect very poor PO rebuild) Amasingly out of traffic it ran fine, started first or second go from cold and reached 105mph as quick as a good one. Good news was it was an easy repair,  one set of good used pistons, gaskett set. Head wasn't perfect (scrored up by rings) but still toured Scotland getting fantastic mpg. Thats where the k3 rules the roost- motorway crusing A road fuel economy. Fort William accross A9? down east coast passing by Edingbourough, Perth, finally filling up at Glasgow. All on one tankfull, mates 250 superdream used over a gallon more fuel in same trip. Round town they used the same, almost to the penny when filling up.

[totty]

No I haven't but I have a tester somewhere so I'll dig it out.
Since the last carb clean mines been a good starter hot or cold and it's also oil tight, but the test might highlight some other issue.

[Yoshi823]

I remember coming across a problem on several Honda fours, not just my own but other peoples as well. The points cam is a sleeve that slides over the back plate of the advance/retard unit that holds the springs in place. There is little or no lubrication on this moving part & so can become quite 'sticky' & not always return the bobweights to the home position after the throttle has been closed after a rev-up. But be aware that if you pull off the cam from the advance/retard mechanism it's quite easy to get the cam 180 degrees out, so make a mark on both parts before you dismantle it. Lube with nothing heavier that 3-in-1 oil.

[Bryanj]

Steve, Honda relied on the gauze in the tap as the tanks were new and hadn't had 25 years of dirty petrol in them so it didnt need to stop much crud or rust. I agree the small ones can clog fairly easy but the last batch i had you simply had tor reverse the flow into a can for a short time and it flushed said crap back out

[florence]

My carbs always clogged until I got fuel filters.  Annoyingly, the needle valve would get gritty and the carbs would flood. 

If you are not too worried about looks, I find the large car ones are the best because they have a good flow rate and they are cheap, so periodically, when they look really dirty, I throw them away and fit new ones.

On the subject of compression; a friend had a 550 many years ago (1987-ish) which he bought as a non runner.  It had been standing for a while in the previous owners garage.  When my friend got the bike going he took it for a blast and was a little too enthusiastic with the throttle.  What he didn't realise, until I had to strip the engine for him, was the piston rings had become gummed up with old oil during its 'rest' and when he thrashed it they all cracked.  However, I fitted new rings for him and it ran a treat after that.

[totty]

Maybe mine has a self preservation device, I had to cover 150 miles before it allowed me to ride enthusiastically.
The filter I've fitted is rather small but it's what looks like a sintered metal rather than paper element. I've found these flow very well for a small size and don't block easily, they probably don't filter all that well either but will hopefully catch anything big enough to block a jet.

[totty]

I found that the feed to the coils had a corroded connection, after cleaning that up and syncing the carbs I've only had a short test ride. It feels allot better but it doesn't pull cleanly from 5,000 up over although in 4th or lower it will still rev to at least 8,000, in 5th it runs out of steam at 80mph.
The fuel filter is still clean.

[florence]

When you say synced the carbs, I assume you mean with vacuum guages?