issue following carb rebuild / rocker gasket change

[Gavin]

Hi guys

Well, I appear to have made one or two errors somehere... my fettling was going so well for a while there!

I popped to top of the motor a couple of weeks back & replaced the gaskets and oil rings there - hoping to seal up the slowly increasing leaks from the rocker cover. She's certainly feeling like there's greater compression now

Following that I removed the carbs (leaking a little, and very grotty) and used the servicig kits from David Silver to replace all the inner parts and gaskets - the bike was running on some very old and flat gaskets all round! Glad to say that the carbs don't leak or overflow now. I also used the drill bit method to re-sync the carbs as they were a little out.

However, now we come to the issues.

1. Number 1 cylinder only starts to fire up after the engine warms a little (the motor sounds like it;s combusing much better following a clean though as there's a more rounded note to the ignition)
2. Number 4 carb now has no fuel running to it - all the others fill fine
2. There's a nasty knocking sound from inside the motor when it's on a very low idle (never there before) - this disappears the moment the clutch lever's is pulled in.

Any ideas on what daft mistakes I've made guys?

Cheers

Gav

[SteveD CB500K0]

Did you replace the fuel lines (all of them)?  I did on my 750K2 and it solved all the fuel feed problems to the carbs. I also ditched the in-line filters which I could blow through but would not let the fuel through...

If the rattle goes away when you pull the clutch lever (they all do that Sir) you need to balance the carbs as the four cylinders are pulsing unevenly and causing unbalance in the clutch basket.  It's when the rattle doesn't go away that you need to worry!

[Gavin]

Cheers Steve

Thought I'd read something along the lines of that cab balance/pulse issue before so that makes a lot of sense. It's the first time I've touched a carb so I wouldn't be surprised if my attempt at balancing didn't quite work perfectly! Off to buy a carb tune I guess.

I'm going to trop the bowl and check the lines today to see where the fuel's stopped at - confusing thing is that it's got fuel in the other 3 so I'm guessing it's a blockage in the carb itseld rather than the line.

[Gavin]

(morgan carbtune now on its way via post)

[SteveD CB500K0]

They are the best. I bought mine from eBay 5 years ago for about 20 quid.

[Gavin]

Just chatted with a mate who's a bit handy in the tuning of cars - specialist in GT40 builds & tuning for racing I believe.

He's got handy bag of tricks to read the cylinder exhaust temp's by lasering the headers. Also just got a new lamda kit that reads the exhaust emmisions to help tweak the mix.

I'm going to have to take a spin up to his place one weekend soon so I can get this properly tweaked, and then look at understanding the whole flat spot and rev range issue that pods and an open pipe seems to raise.