Cant get it running

Hey all, new here, purchased a cb500 which i cannot for the life of me get running

Its got a track wiring loom on it, i have the diagram for this...

Its got spark, with clean/new plugs, gaps are within tolerence

Battery is good

Carbs rebuilt, standard pilots, 125 mains, 1.5 turns out on the mixture screw, needles float valves all good

Checked the timing and thats all as it should be,compression is good

I cannot get it to run, just cranks over.


Any info/advice is appreciated.

Thanks!

are the plugs getting wet when trying to start. If they are dry the tappets may need setting.

Plugs are wet

Richie178
Yes as you say spark good compression good. Then it has to be carbs. Wrong jet. perhaps faulty choke or just needs cleaning properly or carbs over filling. I should be fixable but it will test your patience. Also check for air leaks and all carb rubbers but that would show signs of richness rather than flooding.

Are the HT leads going to the correct cylinders?

Im not sure, will check later.

integrated vacuum tube in fuel tap?

https://i.servimg.com/u/f91/20/51/89/42/20230810.jpg
Thats the coil wiring, top coil pack is cylinder 2.

Is this correct?

Just swap over the HT leads and see if it runs

Swapped the ht leads over and still no joy.

Can anyone tell me which coloured wires goes to the green spade terminal on the coil packs?

Many thanks

consult the workshop manual and then go to the forum.....I suggest

When you check the spark, where do you earth the plugs to? Does the engine have a good solid earth connection?
Try changing the plugs to known good ones. Past experience tells me that some plugs will show you a spark outside the engine, but won't operate under pressure in the engine. Strange but true
90% of running problems on these engines are caused by the coil/ HT leads and plug cap combination. That's why I changed to a more modern coil on plug set up many years ago and still run them today to eliminate the problems. 
If as you say the plugs are wet, then fuel is getting through so with a spark it should run albeit badly if the carbs are not operating properly. If it doesn't run at all then the issue is with the ignition.

As a point to note, Don't rely on a plug because it's new.
There's a lot of cheap counterfeit ones on the market now.

Thanks for the reply chaps, i have another wiring kit to test as dont have much faith in the one thats fitted.


I have consulted the haynes manual but it doesnt state whether its the blue/yelow or black/white wires which should be on the coloured spade connector on the coil pack.

The coils should work whichever way they are wired, one is just more efficient than the other.