Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Honda enthusiast on April 29, 2024, 08:04:33 PM
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Hi all
Just thought I'd ask my floats are at 22mm and it's running very rich, I have Hendler carb kits on the way as I suspect a wire has been used to clear the jets....can anyone please confirm the float height...
Thanks 😄
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Mine were set at 22 mm by Gerben as per manual.
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Ted, thank you 🙂 how many turns out are your mixture screws?â¹
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Hi all
I think I've got enough to go.on, there's a wealth of information on the search feature
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Ted, thank you 🙂 how many turns out are your mixture screws?â¹
I can't help you with that at the moment as the engine has not been started up - 1.5 turns is I believe the norm starting point.
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Just thought I'd ask my floats are at 22mm and it's running very rich, I have Hendler carb kits on the way as I suspect a wire has been used to clear the jets....can anyone please confirm the float height...
You may want to double check your measurement first, by applying this method: http://forums.sohc4.net/index.php/topic,185754.msg2151647.html#msg2151647
I measured 50ml exactly but I wouldn't worry if you measure 2ml more or less.
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Just thought I'd ask my floats are at 22mm and it's running very rich, I have Hendler carb kits on the way as I suspect a wire has been used to clear the jets....can anyone please confirm the float height...
You may want to double check your measurement first, by applying this method: http://forums.sohc4.net/index.php/topic,185754.msg2151647.html#msg2151647
I measured 50ml exactly but I wouldn't worry if you measure 2ml more or less.
Thanks that's a good way of checking, I'll try that later....just at the moment I'm rebuilding the carbs after a strip and clean...all the original brassware is in there but someone has been in there before to take the slides and needles out.
I'm going with what I understand is correct for the US K1 at 22mm float height and needle at notch four of five from the top....if anyone thinks differently please say so....thanks
I found the mixture screws were set at one turn out and float height was 26mm , presumably to compensate
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On factory air filter arrangement I believe the middle needle position is correct.
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1. Float height is the manual is 22mm. But this is just a guide. The tang on the floats when new are tangential to the pivot pin. However after mangling them several times, you may notice that they are no longer tangent. So feel free to adjust the float height to 23 or 24 mm. That little offset is magnified by the ratios of tang to pivot and float height to pivot. As long as your covering the jets it should be fine. Measurement of the amount of fuel in the bowl is a pain and not easily done unless you use a drain screw modified with a clear tube to view the fuel height.
2. If your having trouble with the overflows barfing out fuel, one thing for sure is the needle valve springs over time become unequally compressed and less resistant giving you all kinds of different measurements. I suggest buying new needle valve sets. You will notice the difference immediately when you set the carbs on the bench. The floats will touch the needle valves and not compress the springs at all. Also these stock Keihin carbs use a lot of o-rings which over time will not seal. Especially the o-ring on the needle valve seat. If this one is bad, your carbs will eventually overflow. These needle valves are brass on brass. Some are rubber on brass. So there is no substitute for a good spring in the needle valve.
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22mm Hubert. If the carbs are clean, float valves seating correctly, no pitting in float valve seats, float pivots free and moving, then 22mm measured at the correct place stops any leaks.
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Thanks both of you, Robert and Julie....I have an issue with the float valve springs which have softened with age. When the carbs were inverted the previous owner had set them bang on 22mm but when I set the bank on its side as you had previously written up, Julie the actual heights were more like 26mm. So I set them with your method and cleaned all the passageways with compressed air and carb cleaner can.
It's still running rich and won't start on full choke, when choke is half off it fires up , no fuel leaks but mixture screws have to be out three turns and it will also run with them screwed right out...there's black sooty deposits from out of the drain holes.
I've sent the Hendler kits back, they were rubbish as the main jets did not fit in the retaining clip. To get the float valve assemblies I've gone for Tourmax kits otherwise I'd have asked you for your slow jets, Julie...the air cleaner is new. While I'm waiting for the carb kits to come I'm going to set the points.
Any other ideas anyone 🤔
Thanks 😊
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Not all my bikes need full choke for cold start. Have you got the jet needles set in the correct notch? Do you know if the jet needles are the compatible ones for the jets?. The needles are profiled and if it's not seating correctly due to being worn, or the incorrect part, ie, aftermarket, it will always let fuel through at the incorrect rate. It's obviously over fueling because at full turns out on the mixture screws, she should be running very lean indeed.
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I’ve seen reports of worn carb body where needle jet seats allowing leakage around the jet. Worth checking.
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It's all original as far as I can see inside but the carbs aren't the originals of my 10000 mile bike, there's wear on the cable nipple holders indicating some more use than 10k...otherwise it all looks original with the oe stamps on the needle and jets.
Julie the needle is on groove four from the top, I understand that's where the US bikes were, is that right? The carbs aren't flooding so it's got to be the jets or needle position for it to run so rich?
I've Tourmax kits on the way, would you suggest an alternative fix?
Many thanks David and Julie 😁👍
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Having similar issues with Lazarus at the moment so have moved the needle to middle groove, haven't tried it out yet as our dog has had an operation so looking after her is taking priority over bikes!
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Quite right too, Mick dogs are part of the family 👍
I'm waiting for my carb kits now, I've got a starting point by balancing the carbs and it will tick over smooth at 1100 rpm but to get it to rev cleanly and idle the mixture screws need to be almost out. I'm pretty sure it's the float level masked by the worn needle springs and possibly also the slow jet which might have been cleaned with a wire...both hopefully sorted with the carb kits
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[...] Julie the needle is on groove four from the top, I understand that's where the US bikes were, is that right? [...]
For a full understanding and why some of us hold 4th position of te needleclip for questionable, you may want to consult this overview and read the subnotes in particular.
For an experiment I have my needleclips in 4th. So far I regret it. In all other markets that also had the 627B carbs, 3rd position was standard... Same goes for the markets that had the 649A carbs.
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I'll move my needle to middle (third) position then and see what the result...ATM it's running so rich it won't rev cleanly....cheers 🥂 with a bit of faffing I'll get there
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Any blockage in the air intake, like a forgotten cloth underneath the seat?
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No there's no cloth there, cheers 🍷
Thanks all who helped, I've sorted it now, fitted the Tourmax carb kits and put the needles in the middle groove, float heights 22mm and screws 1 1/2 turns out...super idle now at 1100rpm no clutch rattle...revs cleanly no misfire now...
😄👍✅