Running issues 500/4

[Davecrook1]

I've not long had the bike and finally got it an Mot.  The bike would not Rev passed 5k. Would alway spit and splutter. I took carbs off and the float level was at 26mm so set it to 22.
I adjusted tappets. And the. Looked at timing.

I used the light test to do the static timing. I had the light coming on smack on between the T and F marks but the bike would not start. I then opened the points up a little and the bike starts and runs smooth on tick over.

I balanced the carbs. Took it a ride and it still splutters. I don't know if it's the timing or fuel. Like I say the timing is way off the mark but only way to get it running

Any ideas or help

[Johnwebley]

have you got standard main jet ?? #100
what colour are the plugs.

 is the advance moving properly,

are the plugs gapped correctly.

 is the aircleaner clean ??

[Bryanj]

When timing with bulb the light should come on EXACTLY as the moving mark lines up with the "F" BUT AFTER you have set the points gap at 14 thou. Moving the plate can alter the gap so it takes a lot of time and care to get BOTH exactly right. Not reving suggests carbs

[paulbaker1954]

Sounds to me like either fuel starvation at higher revs OR advance not operating correctly.

Have you rebuilt and overhauled carbs?

Advance is easy to check with strobe if you have one or can borrow one

Have you checked for correct jet sizes that are appropriate for exhaust you are using. Are you running standard pipes or do you have 4-1 or 2-1 pipes as opposed to standard 1-1 pipes

[Davecrook1]

I have a 4-1 exhaust system: everything is new. Plugs and filter too. I've stripped carbs and replaced the rubber seals. Measured the float height.
I have no idea what the standard jets are supposed to be so whatever was on there I put back.

I'm not sure how I find out if the advanced timing is working. It moves when I stripped it down and oiled it. Springs felt ok aswell.

I've had the bike running ok one minute and the next it started the splutter and hasn't really ran properly at higher revs since.

[Davecrook1]

Mixture is set at 1.5 turns out

[mike the bike]

It wouldn't run at all at 180° out, found it by experience.

[paulbaker1954]

Still sounds like a fuelling problem to me

I had all kinds of issues with my 4 until I eventually bit the bullet and used an ultrasonic cleaner on the carbs and replaced all the jets.

After that ran like a new bike. What I found was that 2 of the pilot jets were gunked up and also the primary air circuits in the carbs were also bunged up.

There is a link below to how to check the carb airways are clear I put up in a prior post

I'd start with a full carb clean and see if that helps - of course others older and wiser than me may suggest another path.


http://www.sohc.co.uk/index.php/topic,12451.msg96037.html#msg96037

[bike addict]

Just a thought - have you checked the needle valve clip setting position? I had similar sounding problems with my 500 K0 and a lot of its issues (much spluttering above about 5.5k revs) were caused by an over rich mixture, primarily caused by incorrect needle jet height. Mine were dropped by one notch and, with original (very expensive, David Silver Honda nos O rings in the carbs), the overall affect was miraculous; you could mention CB500 and Swiss watch in the same sentence without blushing!

[jon stead]

Daft question, but what should the needle valve setting be, and which end is it counted from?

[Norniron]

Did u clean out the emulsion tubes from above the main jets?