Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: davidcumbria on August 24, 2023, 07:21:02 AM
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The perils of meddling for cosmetic reasons !
Cured my Simoniz painted barrel in the oven at 200 degrees for 90 min as recommended. The aluminium expanded more than the the sleeve and the weight of the block has caused it to slip down the sleeve. barrel was right way up and was standing on the sleeve bottoms.
My plan is to reheat with barrel resting on cylinder head up side down so hopefully the reverse process will occur and the barrel will drop back onto the sleeves. May not drop fully so when still hot will try to tap the sleeves home with a block of wood. To support the block while tapping was thinking of trying to slide it back down onto the upper case ( pistons not fitted yet ) or support it on some wood blocks. There is not a lot space between the sleeve and barrel at the end of the block to make the latter very reliable. I do not want to bend the block.
I may have to get sleeves pressed in to get completely flush and / or get barrels re skimmed. There is a risk that if not fully home they will drop slightly when engine is run messing up the gas tight joint with cylinder head.
Any one else with experience or thoughts about this ?
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Just reheat in the oven but, put the barrels on blocks and the liners will drop back in to place. Once they have dropped, a quick smack with a copper hammer to make sure they are home ;)
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Barrels only need re-skimming if the liner has changed location to another set of barrels. Have done a few thousand of these in my years ;)
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I chickened out oven baking the block due to the weight in our oven plus I figured it would cure soon enough once the engine was running.
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This happened to me on one barrel and only by about 1/2 mill. I simply hadn’t noticed and only found out when torquing the cylinder head down. There was almighty “crack’ and it took a while for me to realise what had happened. I’d thought I’d snapped the head in half😁🫣
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Just reheat in the oven but, put the barrels on blocks and the liners will drop back in to place. Once they have dropped, a quick smack with a copper hammer to make sure they are home ;)
Thanks that’s reassuring. Also means I can justify buying another tool (copper hammer) - happy days.will update how I get on when hammer arrives next week.
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Just reheat in the oven but, put the barrels on blocks and the liners will drop back in to place. Once they have dropped, a quick smack with a copper hammer to make sure they are home ;)
Thanks that’s reassuring. Also means I can justify buying another tool (copper hammer) - happy days.will update how I get on when hammer arrives next week.
You can just use a block of wood and use a normal hammer ;) I only use a copper hammer as i have one .
You will have to knock them down while it is hot :)
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All done now. 200 degrees for 30 min in the oven and the sleeves were completely free to drop back into place no real need for tapping home but it was a comforting check. The intakes were perfect for resting the block on. No need to skim or use a press as mentioned on US forum so hopefully reassuring to someone else in future.
Thanks for the advice Graham.