Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Topcat on March 11, 2019, 11:33:53 AM
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Hi Guys,
Trying to find the piston to bore clearances for the following 0.5 oversized pistons.
https://www.davidsilverspares.co.uk/CB550F2-SUPER-SPORT-1977/part_326896/
Anyone happen to know the manufacturer of these? or better yet what the clearances should be?
Cheers
Topcat
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Same clearance as std which is in the manual
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Same clearance as std which is in the manual
Hi Bryan,
Looking at a few manuals (clymer, haynes and the service manual) they all speak about piston ring max side clearances, piston ring gaps standard vs max. However when I gave these to the machine shop they said these weren't what they needed and they wanted piston to bore clearances.
Could you confirm which clearances you were saying are in the manual?
Cheers
Topcat
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If you download the proper workshop manual from Ash,s aladins cave it will give you max/mim bore size plus max/min piston size. All my manuals are packed away so i can't do it for you
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If you download the proper workshop manual from Ash,s aladins cave it will give you max/mim bore size plus max/min piston size. All my manuals are packed away so i can't do it for you
Of course, I understand. Unfortunately it looks like the aladdin's cave is having issues with the 550 folder either being empty or tree controls not functioning. I've found some workshop manuals elsewhere with min max bore plus min max piston sizes. However I'm either completely missing something or there is an error in the manual (probably not the latter). Is the standard piston diameter really that variable?
However if I assume the miss print is 58.47 then I'd say clearances are 0.01mm - 0.04mm, would I be correct in these calculations?
[attach=1]
Cheers
Topcat
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The 550 is just a suplement to the 500 mate so try that and those clearances sound about right, they need to bore to the smallest clearance AND INSIST ON THAT no matter what they say about being tight and siezing. I would doubt there is any measurable difference in pisto size accross a set of 4.
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If you download the proper workshop manual from Ash,s aladins cave it will give you max/mim bore size plus max/min piston size. All my manuals are packed away so i can't do it for you
Of course, I understand. Unfortunately it looks like the aladdin's cave is having issues with the 550 folder either being empty or tree controls not functioning. I've found some workshop manuals elsewhere with min max bore plus min max piston sizes. However I'm either completely missing something or there is an error in the manual (probably not the latter). Is the standard piston diameter really that variable?
However if I assume the miss print is 58.47 then I'd say clearances are 0.01mm - 0.04mm, would I be correct in these calculations?
(Attachment Link)
Cheers
Topcat
If you are using aftermarket pistons, you need a piston to bore of 0.026 mm or 1 thou ;) If anyone that is doing your re bore tells you that this is too tight, walk away and find someone that knows about Honda engineering.
These are cheaper than Sliver >>> www.ebay.co.uk/itm/75-77-HONDA-CB550F-0-5mm-OVERSIZE-PISTONS-SET-4-PISTONS-INCLUDE-10-CB550KPS-1/263451814044?hash=item3d56f3a89c:g:MCEAAOSwNRdX6M6z
-
If you download the proper workshop manual from Ash,s aladins cave it will give you max/mim bore size plus max/min piston size. All my manuals are packed away so i can't do it for you
Of course, I understand. Unfortunately it looks like the aladdin's cave is having issues with the 550 folder either being empty or tree controls not functioning. I've found some workshop manuals elsewhere with min max bore plus min max piston sizes. However I'm either completely missing something or there is an error in the manual (probably not the latter). Is the standard piston diameter really that variable?
However if I assume the miss print is 58.47 then I'd say clearances are 0.01mm - 0.04mm, would I be correct in these calculations?
(Attachment Link)
Cheers
Topcat
If you are using aftermarket pistons, you need a piston to bore of 0.026 mm or 1 thou ;) If anyone that is doing your re bore tells you that this is too tight, walk away and find someone that knows about Honda engineering.
These are cheaper than Sliver >>> www.ebay.co.uk/itm/75-77-HONDA-CB550F-0-5mm-OVERSIZE-PISTONS-SET-4-PISTONS-INCLUDE-10-CB550KPS-1/263451814044?hash=item3d56f3a89c:g:MCEAAOSwNRdX6M6z
OK the place I took it too seem aware of the honda engineering tight clearances. Could you guys confirm should I be looking at 0.01mm or 0.026mm? I'd previously asked for 0.01 and was pretty insistent on it based on bryan's reply but if it's 0.026 for the aftermarket ones I'll have to call them back sharpish.
Cheers
Topcat
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0.026 mm is equal to 1 thou of an inch.....you need 1 thou clearance
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I was working with Honda parts not aftermarket, trigger has used way more of those than me so i would use his numbers.
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You need 1 thou clearance on the aftermarket Sliver pistons. And the pistons need to be matched and numbered to each individual bore ;)
I have had 1mm over size pistons from Sliver that were only 0.69mm over size :o
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You need 1 thou clearance on the aftermarket Sliver pistons. And the pistons need to be matched and numbered to each individual bore ;)
I have had 1mm over size pistons from Sliver that were only 0.69mm over size :o
Thanks Guys, appreciate it, yes sent all four pistons over for boring to match each of the cylinders. Have gone for 1 thou clearance.
Regards
Topcat