Mike's CB550 Project

[Bryanj]

I think so, somewhere i have a nos plenum bought years ago but gawd knows where

[taysidedragon]

Yes, thanks. It is the portion that is inside the plenum I am trying to work out as 2 of the boots are concentric and 2 of them have an angled portion that sits in the plenum. I am assuming that the one in your picture (carb #1) is angled on the inside of the plenum, away from the choke lever and towards the paper element?

On the original Honda rubbers there is a small raised pip on the rubber which lines up with a raised pip on the plastic airbox. Pattern rubbers may not have the pips.

[Mike_Berkshire]

Thanks for your replies chaps. I think I haven't been explaining myself correctly. I have bought a set of the rubber boots that connect the carb intake side to the plenum. In the set are 4 boots. They are not all the same. 2 of the boots are straight and 2 have a bend in them on the portion that is hidden inside the plenum. I have assumed that the ones with the bend in them are for carb 1 and 4 and the bend is angled towards the centre-line of the plenum where the air flows in from the paper filter. Below are 2 photos ( I hope!). One shows the straight boots fitted to the plenum for carb 2 and 3; the other photo shows the angled boot which I have assumed is for carb 1 and 4. Am I making sense?

[taysidedragon]

You're correct with the rubber arrangement.  When the angled rubber is fitted to 1 or 4 the angle should line it up with the openings in the plastic airbox.

[Mike_Berkshire]

Excellent; thanks Gareth!

[Mike_Berkshire]

Air box etc now fitted thanks for the info!

[Bryanj]

How many undamaged complete knockles you got left?

[Mike_Berkshire]

Im good thanks Bryan. I did have an assistant however which was very helpful. I did have to remove the battery box and clutch cable to make room and fitted the two outer unions once the plenum had been wrestled into place. Very fiddly though!

[Bryanj]

Makes you think the line starts with the carbs on a piece of string, bit like the land rover steering box

[Mike_Berkshire]

And now its time for the electrics. Its going to take me a while to clean up and buzz through the old loom. Having stripped out the burnt out earth wiring/connectors I am left with a mostly 'naked' loom. Most of the outer wrap was carefully cut away and the wiring is now held together with cable ties. I cant make up my mind whether to fit the loom as-is to test it and run the bike and then, once all good, remove and re-wrap or to replace the burnt out wires, replace damaged connectors, re-wrap and then fit. Im just worried that if I do that I will find I need to open it up again - any thoughts?

Seeing that the earth wire from the rectifier through to the ring terminal at the coils had burnt out I want to be sure the earthing is sound. The engine mounting bracket where the battery earth terminal is fitted is not painted and I am assuming I should also ensure that the engine casting lug that is behind it is paint-free (its not at the moment). What other precautions should I take to ensure good earth pathways?

Thanks, Mike

[Mike_Berkshire]

I bought a new sub-harness and left hand switch control unit as the originals were completely trashed. Even though both were advertised as being for the '76 K2 3 of the wire colours were different in the handlebar control and there were a couple of differences in the sub-harness. Thanks to the answers from the forum I think I have sorted out these differences.

Im now slowly fitting everything back to the bike. I have mislaid the Ignition Coil wire protector (504 323 000) and I am assuming that if I cant find it then provided there is some protection between the coil wire and the weld seam in the frame to stop rubbing this is not an essential part?

I have also removed the tatty old insulation tape from the battery earth strap - see picture below. I think this may well have contributed to the poor earthing in the bike? I will be replacing the earth strap.

[Mike_Berkshire]

Progress today. After setting the points etc and checking I had a good spark on all 4 plugs/cylinders I had the opportunity today to try firing up the engine. The bike started almost immediately and the oil light went out; I removed a tappet cover and could see there was plenty of oil finding its way to the top of the engine. From the sound and throttle response it seemed clear it was firing evenly on all 4 and the Delkevic 4 into one sounded great. Once it had warmed up I took the choke off and it ticked over quite nicely at just over 1000 rpm. It was a bit more clattery than I was expecting but I remembered that I hadnt adjusted the camchain tensioner since I had rebuilt the top end. After blipping the throttle I got a spot of hanging but didnt run it for too long as I wanted to get the camchain adjusted. As I didnt know how long it would be until I got the next opportunity to run it I let it run out of fuel to stop so the carbs would be left dry.

As it turned out I had some time later in the day so I adjusted the camchain tensioner and ran the bike again. There was less top end noise than previously but still more than I would expect so I will check/reset tappet clearances again before the next test. This time I got fuel leaking from carb number 2, I tried tapping the floatbowl with a piece of wood; quite hard. This made no difference, the leak seems to be from the top of the float bowl as opposed to out of the overflow pipe - this needs more investigation. Also, the hanging once warm was more pronounced as once warm and the throttle blipped it sat at 3000 rpm. Theres plenty of threads on hanging i will read through to see if I can work that out.

On the overflowing/leaky carb I am guessing there is no way round that apart from taking the carbs off (and the plenum etc etc - aaargh!) to investigate that - if anyone has any tricks and tips on that I would be very appreciative!

Overall though Im really pleased with the progress and thanks again all for the help to get this far.

[Nurse Julie]

Well done Mike, I bet you're really chuffed to get it up and running. In the great scheme of things, the snags you have are quite minor. Well done.

[McCabe-Thiele (Ted)]

You might know this already Mike, I used Kens method for adjusting the cam chain. Holding the kickstart  by hand so you are pushing against the compression, having released the tensioner lock nut. Having released the lock nut the chain tensioner will take up the slack, then just nip the lock nut in position. You can then tighten it up properly by using the screwdriver slot to hold the screw  and a spanner to tighten it up.

Pretty sure that's how I did mine iirc.

[McCabe-Thiele (Ted)]

Apparently I have credited the wrong member it was Bryan, not Kens method.