Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: daz-j on March 02, 2021, 09:21:54 PM
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Hi all, I'd be grateful for a little advice please on assessing the condition of the cylinders, as I have no previous experience of this. I've measured all 4 bores, each in 4 positions. Each one sizes up the same, slightly oval at 51.03-51.05mm - so to my understanding that's within the service limit.
All have what I would say is light scoring, which can be felt with fingernail - the photo below is probably the worst case.
[attach=1]
Would this be regarded as acceptable condition, a candidate for re-honing, or even reboring?
Thank you.
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If you can feel the scuffs with your fingernail, it needs a rebore. You should not be able to feel anything at all with your nail.
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I have seen worse run but its not ideal, re ring with ade glaze would probably get you about 80% compression after settling in, to be a "good" job needs oversize kits and rebore which costs, its your money and time so your choice, personally i would bore it
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Yep,
agree with what's been said above, but here's another option available to you.
Low mileage second hand barrels and pistons here:-
https://www.ebay.de/itm/Cylinder-Compl-With-Piston-And-Rings-Cylinder-Piston-Rings-Honda-CB400F-Used/265053325887?hash=ite (https://www.ebay.de/itm/Cylinder-Compl-With-Piston-And-Rings-Cylinder-Piston-Rings-Honda-CB400F-Used/265053325887?hash=ite)
I can recommend this place, they are sort of like the German version of DS, but they also import low mileage bikes from the states and dismantle them for spares.
I bought CB750 barrels and pistons from them which were in excellent condition and ready to fit with new piston circlips.
They speak perfect English, so you could contact them and ask for close up photos of the cylinders etc.
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You can get a set of quality oversize piston/rings from Cruzinimage for about £120 plus the rebore cost - much cheaper than SH set
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Thank you for the advice, I'm thinking my preference is probably to go for the rebore option, but nothing is straightforward at the moment – there’s only one engine machine shop that I know of locally, they seem to be well regarded but unfortunately are closed due to Covid. Others further afield do seem to be open though, will have to give it some thought.
Regarding a new set of pistons, is a rebore to suit 0.5mm oversized pistons the standard practice? I’ve seen Cruzinimage recommended on here before, but didn’t realise until today that they’re US based, unless there’s a UK outlet I'm missing?
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Cruzinimage are in Japan. Extremely easy to deal with and buy from. If you can't find someone more local to do a rebore, we (That's Graham, Trigger) do rebores etc and 90% of the engines are sent to us and returned via courier, so it's all very easy really.
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Found these but seems damned expensive to me, no idea how much Cruzin charge for the same amount.
https://www.ebay.co.uk/itm/Honda-CB400-Four-Piston-Rings-Bolts-Kit-Original-0-25/254706583305?hash=item3b4db20709:g:MC8AAOSwV6VfTgYW
Hi thanks for the link but crikey - £427.33 - damned expensive indeed, struggle to justify that I'm afraid. The Cruzin +0.5mm set are priced at $100.00, I assumed that was US Dollars but not sure now that Julie has pointed out it's a Japanese business.
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I've had 2 sets of pistons (for 750) and a set of rings for the 500 - luckily never paid import duty so far!
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Cruzinimage are in Japan. Extremely easy to deal with and buy from. If you can't find someone more local to do a rebore, we (That's Graham, Trigger) do rebores etc and 90% of the engines are sent to us and returned via courier, so it's all very easy really.
Trigger is recommended and will do a superb job.
Don't ask to many questions at Cruzinimage or you will suffer the consequences ;D
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Just as a point of reference Julie, I've a spare set of barrels that are passed their best and going on a separate build that need some attention, where its been sitting for years the rings have marked the barrels and could do with a rebore and new pots. What would the ball park cost be for that with you and Trigger?
I've done my first Cb 4 mill now so keen to do this one now its all fresh in my head.........like yer do ::)
cheers in advance
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Just as a point of reference Julie, I've a spare set of barrels that are passed their best and going on a separate build that need some attention, where its been sitting for years the rings have marked the barrels and could do with a rebore and new pots. What would the ball park cost be for that with you and Trigger?
I've done my first Cb 4 mill now so keen to do this one now its all fresh in my head.........like yer do ::)
cheers in advance
I'll send you a PM later Roo.
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Fanks :)