Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Norniron on May 05, 2014, 11:11:18 PM
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Look at the mess trigger made
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And another
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A little Black Beauty. Only problem if you look at the third picture, the caliper is sitting high off the disc. That high that i can get my little finger in the gap. The pads are only touching 80% of the pad to the disc. Can anyone explain why???
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mismatch of caliper pivot arm and disc ...ie one or t'other isnt the correct 550 part ?
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I would say that the disc is too small. What does it measure?
We can compare it to ours.
Steve
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Yes Ewan 550. It looks like the disc is too small. Will look again tomorrow.
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Disc on my 500/550 mongrel is 277mm diameter. 500 & 550 share same disc.
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Ewan, cheers for the picture.The disc is 277mm and the caliper is the wide body type that matches the arm. Norniron will post some more pictures later. I can not work this out. I have just sold a 550F1 and that was fine. Never seen anything like this before.
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Oddjob, i am sure that the K3 had the same forks. If the wrong sliders, that would mean that the mounting points would have to be 10mm lower. This would make the mudguard rub on the tyre of a 19inch wheel.
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I know some 500 / 550 forks do vary in length but cannot recall where this variation happened though I'm pretty sure the 500 has the shorter forks and k3 longer, but as for 550f I cannot comment, not had one.
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Triggers problem child
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The two types of arm ,on the bottom is a k3 arm
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Norniron, so which arm is the top? if the bottom is K3.
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so next we want to measure the length of the lower fork case ? I have three sets... mix / match of 500 and 550's and not sure which is which . (Laterz ... the one marked 341 seems to be from a 750 K3-K5 and / or 550K1 All three are idential, save for one which is about 5mm longer. (550K3 ?)This one might be a 550K3 one) .. but even in this one the distance between the pivot mount bolt holes and the bottom are identical ... so all three sets would result in same caliper to disc relationship. See attachments:
[attach=1][attach=2]
Are we sure its not the wrong caliper arm thats on the bike ? I'm trending towards this being the problem
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Norniron, so which arm is the top? if the bottom is K3.
Cb500 so ive been told
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The two types of arm ,on the bottom is a k3 arm
On a tangent ... do those two have different horozontal offsets ? ... I had a right bugger of a time setting up my dual discs ... i think beause I was using two different caliper arms. Of the three I was trying, one has 5 5 stamped on it, one has 8 8 stamped on it and one has M2 stamped on one side and an 11 on the other. Of the three, one is distinctly asymmetrical in the plan view, ie it bends more one way than the other horizontally . The other two are symmetrical. Also, one is of thicker diameter than the other two at the end where the pivot pin goes through it.
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Your calliper is 50mm bolt centres.change it to the smaller calliper and arm and i rekon its sussed
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The two types of arm ,on the bottom is a k3 arm
I ve lined them up so the fork mounting bolts are in line for the pic.
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Ewan, the K3 and F share the same part number on the left fork case. I still have the old pads from this caliper and if it was like this before there should be a worn step in the pads. But they are flat and smooth.
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is it possible the top bit of the pivott is on upside down and throwing things out?
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I will measure it up against the 500K0 folks tomorrow.
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Nope, not a 750 caliper. They bolt from the back to the threads in the main body. Bitsa, sent me a 750 arm and that is 42mm.
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Cheers oddjob, will try again tomorrow. The F1 i have just sold had the same caliper. I have it in my head that there was two types, one being a wide body.
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It's the wrong arm and caliper Trig. Just compared it to a 500/550 arm and it's different. The 500 arm doesn't have a slope on the bottom, it has raised edges on top and bottom and no segment like a slice of cake on the lower edge like the one in the pic has. Plus the caliper looks different and the bolt holes are too wide apart on yours. It's the wrong one Trig, no doubt at all in my mind.
agree here., just been out and measured mine ... caliper bolt holt spacing is 42mm. I also have a spare caliper arm in ma boxobits ... it is 50mm between aliper mounting holes and when I line it up against the fork mounting points, it sits a good bit higher than the 42mm bolt spacing ones do . The 50mm one is marked "ART" on one side and "5" on the other .. any idea what its off Ken ? Also agree the inner face of the caliper looks wrong.. or different to mine anyway. I reckon NOrn is right too... swop caliper and arm out for 42mm bolt spacing versions and sorted
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Norniron, so which arm is the top? if the bottom is K3.
Cb500 so ive been told
dont think top one is a 500/550 one Norn.. should be a valley between adjuster bolt hole and bottom edge (see pic for mine) . I think all the 550 and 500 models share the same arm .. although there are two part numbers they appear interchangeable - 45115-323-010 & 45115-390-003 according to http://www.motogrid.com/p/OEM-Parts
One on top in your pic has a has a raised bit instead of a valley. Does the top one in the pic have 50mm caliper mounting bolt spacing... looks like wider spacing in your pic than the bottom one
What is this bleeding version with the 50mm bolt spacing from ?
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Not really any idea Ewan. It's clearly something from around the 70s, something that used the same sort of design as the 500/550s. Maybe a 400/4 or one of the 750s like say a K4/5. I can't think of anything else offhand, maybe Bryan can shed some light on it.
..... over to Bryan then ;)
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What size is the piston? Later 750's had a bigger piston and bigger calipers with different bracket arms and of course bigger diameter discs so looks like one of those, if you have a 750 disc about you could always fit that and make it a real mongrel, just as long as you have a good memory or accurate note book!!
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Ewan, Oddjob, This is why i am so confused on this 50mm arm. I was going to do a twin disc on the 550F1, and had matched the two 50mm caliper arms and the two wide body calipers up to fit the F1. Was about to start the double disc conversion when someone made me an offer on the bike. So that got sold.
So then i put the 50mm back on the black one.(where it originally came from) And the confusion started. I have a number of arms and calipers but, all the rest are 42mm. I took it that the 50mm was from the F1, F2 , K3 and 750K. The 42mm where from CB250, 400/4, 500T. It was not until Bitsa sent me an arm that was 42mm from a 750K that i understood that the 750K had the smaller one also.
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OK, everything fits and lines up. Nornion was right. I have informed him off-line. Cheers for all the info. The F1 i sold must of had a bigger disc. From what Honda CB is another question. Anyone have any ideas?
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I have just spoke to the new owner of the CB550 F1 and he said the disc is 295mm. This explains why it fitted OK.
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I have just spoke to the new owner of the CB550 F1 and he said the disc is 295mm. This explains why it fitted OK.
This thread just goes to show how uik and effective this forum is at getting to the bottom of tings ... brilliant ;D .. so the 50mm arm/ caliper comes from later 750's + 550F1 ?
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Ewan, now that is another question. Anyone out there have a CB750 F1 or F2 that could clear this up. Ewan and I may have some parts for you ;)
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Ewan, now that is another question. Anyone out there have a CB750 F1 or F2 that could clear this up. Ewan and I may have some parts for you ;)
;)
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Very interested to know the answer to this too. The second disc setup I recently sold also has the same problem.
I removed it from a mates non running '77 550, so it either had a front end swap at some point or it was a model change.
I believe the disc is the correct 550 size, but caliper and bracket do not match with the new owners forks.
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Very interested to know the answer to this too. The second disc setup I recently sold also has the same problem.
I removed it from a mates non running '77 550, so it either had a front end swap at some point or it was a model change.
I believe the disc is the correct 550 size, but caliper and bracket do not match with the new owners forks.
yep, that looks like the same 50mm bolt hole centres caliper arm ... which then seems odd that it came off a 500, unless the disc was also a larger 295mm non standard disc
Did the disc also come off the 500 ?
Does the purchaser mean that the caliper arm bracket holes dont line up with the holes on the fork case ?
What bike is he trying to fit it to ?
.. and he might not want to use the stainless bolts ... was told their low tensile strenth makes them a bit dodgy as disc bolts 8)
http://www.sohc.co.uk/index.php?topic=6550.msg35809#msg35809
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I second that about the bolts Ewan. You need High tensile bolts.
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Very interested to know the answer to this too. The second disc setup I recently sold also has the same problem.
I removed it from a mates non running '77 550, so it either had a front end swap at some point or it was a model change.
I believe the disc is the correct 550 size, but caliper and bracket do not match with the new owners forks.
yep, that looks like the same 50mm bolt hole centres caliper arm ... which then seems odd that it came off a 500, unless the disc was also a larger 295mm non standard disc
Did the disc also come off the 500 ?
Does the purchaser mean that the caliper arm bracket holes dont line up with the holes on the fork case ?
What bike is he trying to fit it to ?
.. and he might not want to use the stainless bolts ... was told their low tensile strenth makes them a bit dodgy as disc bolts 8)
http://www.sohc.co.uk/index.php?topic=6550.msg35809#msg35809
.. and given what bryan says re pistons .. if the piston and seal are standard 500 ones , they might not fit that caliper if the caliper fits the caliper arm :-[
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He might be along soon....
As for the stainless bolts - I know it can be a much discussed subject and don't want it to become the subject of this thread but my reasoning was that lots of modern bikes use 6 x m6 bolts to secure the brake discs, these are m8 and they aren't subject to anywhere near the braking forces that modern brakes produce. I think it would be one hell of a shear force to break 6 x 8mm bolts, plus there is the resistance to corrosion etc.
Good enough for an aprilia rsv4, so it's good enough for me
http://www.pro-bolt.com/stainless-steel-disc-bolt-duca-ti-aprilia-m8-x-20m-fl-head.html#.U2vqgSe9KSM
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He might be along soon....
.. think I just saw him passing the window with a package under his arm 8)
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If A2 stainless, they are very soft. The modern bikes are High tensile and a lot are chromed.
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I've mentioned this before and I still don't understand the physics.
Surely your tyre is going to break loose long before enough stress is put on those bolts.
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Les, the stress is in the hub area. And what does a tyre have running in it? High tensile steel. A tyre is a woven compound.
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I've mentioned this before and I still don't understand the physics.
Surely your tyre is going to break loose long before enough stress is put on those bolts.
repeated stress = fatigue = decreasing strength = potential for sudden and catastrophic failure . .... better safe than sorry in any case for the sake of a fiver ?
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I agree with oddjob, to the best of my knowledge all the 500/550 (including the twin) discs and calipers are the same, I think a 750 one was fitted possibly under the assumption that a bigger diameter would give better braking
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The next question is what 750?. Most of the 750K had a caliper that bolted from the back, until the K8 which had a front bolted caliper. The K8 shared the same caliper as the 750 F1. The 750 F2 had a totally different set up, shared with the 750KZ and KB. I have never seen this arm with the 50mm space on any 750's. There must be someone who has this 50mm/wide body caliper fitted. Come on now, don't be shy.
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The next question is what 750?. Most of the 750K had a caliper that bolted from the back, until the K8 which had a front bolted caliper. The K8 shared the same caliper as the 750 F1. The 750 F2 had a totally different set up, shared with the 750KZ and KB. I have never seen this arm with the 50mm space on any 750's. There must be someone who has this 50mm/wide body caliper fitted. Come on now, don't be shy.
I've asked the over on the 750 page trig.. using pptom's photo
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Ewan, if it comes back with there from a special sand cast, i will give you a fiver for our 50mm arm ;)
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pptom .. if your still about have gander at the answer at http://www.sohc.co.uk/index.php?topic=6573.0. Yer man might be quite happy with his potentail resale price :)
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Just read that Ewan, thanks very much - coming to an auction site near you soon...
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The bolt spacing on my 750F1 is 50mm, the 750K7&8 also use the same caliper. Until D.S.S. had some replicas made recently they were really hard to find in useable condition. So Trig, either get a 750F1/K7 or 8 disc, or sell the caliper and arm and fit 500/550 items, the 750 caliper also uses a marginally bigger piston and seal, and the seal is 3 times the price of the 500/550 item!
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