SOHC.co.uk Forums > Project Board
1978 Honda CB550 Supersport - My first retro bike rolling restoration!
woody928:
--- Quote from: Oddjob on June 09, 2020, 03:13:42 PM ---Pretty sure the loom connections will be fine, there are in a small box just below the coils, watch the screw holding the lid on, it rounds off for fun if your not careful. Drop some grease on the threads when you refit it.
Considering the parcel was posted first class signed for that's not good service from the PO, should have been with you well before that.
--- End quote ---
I'm keeping my fingers crossed! I know the one, its been out to give me access to the coils which have now been replaced and the new cables rerouted. Fortunately mine has come out ok, I'll certainly give it some TLC though. It looks like the weather is finally going to give me a break this weekend so I can finally get cracking so hopefully some positive updates to follow.
You're parcel wasn't the only one delayed through RM, they're clearly struggling but thankfully it arrived safe!
woody928:
Well its fair to say its been a very busy weekend and finally some serious progress made.
The new coils have been fitted up and replaced, two spark plugs replaced (I'm waiting on a thin-wall socket to get to the other two), refurbed points plate fitted up and static timing set. I tried to adjust the cam chain tensioner and followed all of the steps however the adjuster when loosened didn't really seem to snap back when turned using a flat head screwdriver. That one seemed very odd so I just nipped it back up and got the bike running to check how we were running and I've back to firing on all four cylinders and sounding a little healthier albeit clearly with serious fuelling issues.
With this done it was time to get cracking and get the carbs out and stripped to be rebuilt. Fuelling is clearly a big issue to running as when the engine is revved there's all kinds of confusion and hesitation with revs rising and falling of their own accord. Getting the carbs out proved simple enough however it's clear that all of the jubilee style fasteners used are well past their best. More rounded screw heads and very tired looking metal. I'm looking to replace the lot with new stainless versions once I've got them measured up. If anyone has any recommendations though then I'm all ears.
IMG_8020 by Mark Woodrow, on Flickr
IMG_8024 by Mark Woodrow, on Flickr
IMG_8029 by Mark Woodrow, on Flickr
Carbs taken into the workshop and on the bench and it's been the meticulous job of totally stripping them down piece by piece and checking for wear while keeping each carb separated for reassembly. The below linked video by classic octane has been my bible, honestly Taylor is the man who's made this possible, his guidance is phenomenal!
https://www.youtube.com/watch?v=JFTOfYl5BSc
Last night I spent countless hours getting to the point that each carb was fully stripped to its bare bones. I've documented a number of screws which have seen far better days and am ordering stainless replacements so that there's new fixings where appropriate. It goes without saying that these have been stripped before, with several bodges along the way... The bottom float bowls for example each now appears to have been re-drilled and tapped with at least one securing M5 securing Allan headed bolt in place of the factory M4 JIS screws. No idea why, however now I have no choice but to go with it.
It also appears that someone attempted some zinc plating a long time ago with very mixed results however now I'll be left with the bodies finished in raw metal form and caps and float bowls in faded zinc plate but that's the way it goes.
IMG_8050 by Mark Woodrow, on Flickr
The fuel could have looked a lot better, its certainly fairly dark I think. Is this due to rust from the fuel tank? Something to be looked at? I'll certainly be refilling with fresh fuel before going anywhere.
IMG_8040 by Mark Woodrow, on Flickr
It also comes as no surprise that all of the fuel lines were petrified and just plain dangerous in places, the years certainly haven't been kind to the fuel lines, once of which literally broke off around the jubilee clip. You do wonder when this job was last done.... I now need to ascertain the correct pipe sizes to get these ordered.
With everything stripped down I've put my new 6L Ultrasonic cleaner to good use and put each carb and its fully assembly through on a 30 minute cycle at around 65 degrees with a carb cleaner solution. Following this each carb has been individually cleaned by hand, all channels checked for clearance with compressed air to make sure there were no obstructions and all brass components polished up or wet and dry sanded in the case of the carb float pins to get them sliding through nicely again. There were some small battles with removing the needles as the screws were locked in place and needed a heavy dousing of Plus Gas to get cracked, one screw still rounded its head but still came out thankfully. My first purchase of magnetic JIS screwdrivers has honestly been worth its weight in gold, they're incredible!
At this stage I think functionally everything is as good as it can be now. I've been really impressed by the cleaning results from this, the water colour and dirt its taken off was pretty shocking!
IMG_8093 by Mark Woodrow, on Flickr
IMG_8055 by Mark Woodrow, on Flickr
IMG_8059 by Mark Woodrow, on Flickr
IMG_8068 by Mark Woodrow, on Flickr
IMG_8082 by Mark Woodrow, on Flickr
IMG_8084 by Mark Woodrow, on Flickr
IMG_8085 by Mark Woodrow, on Flickr
IMG_8096 by Mark Woodrow, on Flickr
I noted that these tabs on both sides were bent on disassembly, I've hammered them flat again however one is now showing a hairline crack which concerns me somewhat. Any idea what these are and how crucial this tab is? I'd have no idea where to find a replacement :-[
IMG_8062 by Mark Woodrow, on Flickr
Next steps are sourcing replacement items where appropriate having measured everything up. In terms of screws I've come across MrMegaPack.co.uk which seems to have a huge selection of fittings for our bikes and am putting in an order for one of their 'Megapacks' which will give me all of the commonly needed screws to hand in stock going forward.
I would be very grateful of some assistance with regards to jetting and needles as I have no idea if what I have fitted is factory or changed and whether any adjustments should be replaced. Looking at least one of the secondary jets it appears to have previously been mauled and damaged in a few areas so should at the very least be replaced.
IMG_8099 by Mark Woodrow, on Flickr
IMG_8100 by Mark Woodrow, on Flickr
Currently though it was running:
98 - Main Jets
38 - Secondary Jets
273004 - Needles (needle height was set one ring down from the highest adjustment point)
I intend to keep using the stock airbox and the bike has fitted a 4-1 system with a Marshall muffler at the rear. I'd like to eventually replace this however for now its what I'll be running and need to bear in mind for my setup. Do the above size jets and needles sound correct? Should I been looking at other needles or jets?
Does anyone know where replacement jets can be sourced? At the very least one should be replaced...
Below are the pics of where I started to where I currently stand, lots of progress made however clearly lots of work still required for reassembly and setup once all of the requisite items and sourced and refitted. Any observations or input gratefully received :D
IMG_8105 by Mark Woodrow, on Flickr
IMG_8107 by Mark Woodrow, on Flickr
IMG_8110 by Mark Woodrow, on Flickr
IMG_8116 by Mark Woodrow, on Flickr
IMG_8118 by Mark Woodrow, on Flickr
Also these are the carb needle securing screws, one of which is damaged. Is there a reason for this little spot on the top? They all have one so I can't imagine its a coincidence?
IMG_8120 by Mark Woodrow, on Flickr
Bryanj:
Its to tell you are jis not phillips or pozi.
Good luck with the insulator clips, them must NOT be any wider or it will cause air leaks
woody928:
--- Quote from: Bryanj on June 14, 2020, 06:47:01 PM ---Its to tell you are jis not phillips or pozi.
Good luck with the insulator clips, them must NOT be any wider or it will cause air leaks
--- End quote ---
Well you learn something new every day!
Are the insulator clips the ones which hold the carbs to the rubbers between the manifold and airbox?
Also any ideas or insight on the jetting/needles?
K2-K6:
Seems that currently the view is that original Kiehin jets are simply more accurate than alternative replacements. Which is highly desirable for such fine metering these carbs have to do.
If the main jet is just one that has the outside a bit tatty it would be worth filing off the sharp burr and using that with new o-rings, as oddjob indicates, to get a full working set.
The damage hasn't impacted the critical surfaces as far as I can see from your pictures.
Nice work so far, it'll definitely pay off when running again.
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