Post by: Erwin83 on February 01, 2020, 09:49:23 AM
I found a little surprise in cylinder 4.
Now I have another old 350 cylinder block on the shelve, also with damaged cylinder due to a piston failure.
Is it possible to replace a liner?
If so, how?
Post by: Trigger on February 01, 2020, 10:43:08 AM
Post by: Erwin83 on February 01, 2020, 10:56:01 AM
Plus: that will mean 4 bores, 4 pistons, 4 sets of rings
Whereas if i replace the sleeve, i can fit 1 other standard size piston and just do the rings.
Matter of cost vs benefit...
Post by: Erwin83 on February 01, 2020, 11:01:23 AM
Post by: the-chauffeur on February 01, 2020, 11:28:13 AM
Usual caveats apply: make sure there's nothing rubber left in/on the assembly - like the rubber rings that hide around the liners under the block (or the fin spacer plugs on the '750s) - and if you're doing it in the house, clean the whole thing thoroughly before you start. Even then, it's probably going to get a bit smokey . . .
Refitting is basically the same process in reverse, but when you do it, put the assembly upside down so the block falls onto the liners as they heat up. And if you're swapping liners between blocks, don't forget to check they seat properly and the top faces are completely flush. You may need to skim the deck depending on how closely matched the liners are. I tend to use the sandpaper-on-glass/MDF technique for that.
Post by: Erwin83 on February 01, 2020, 11:38:45 AM
Post by: Erwin83 on February 01, 2020, 12:07:11 PM
Baked at 225 degrees celcius for 15-20 minutes.
I put the sleeve i wanted to remove on a spanner, so at first sight when it came up, i removed the block from the oven and tapped it out. No force needed at all.
This is why I love forums :-)
Post by: Erwin83 on February 01, 2020, 01:14:27 PM
Allthough it does seem to need a refacing, as even with some massaging with a block of wood and a hammer, i can't get the cylinder to seat completely flush. Just a hair though.
Post by: mickwinf on February 01, 2020, 03:15:36 PM
Post by: Erwin83 on February 01, 2020, 03:32:43 PM
Just be aware cylinders wear oval so piston may not fit, Trigger told me that!
Do they wear, or do they warp?
In case of wear, i would assume pistons only fit easier (with oil consumption as a result). If the cylinders warp (i can’t see how), I can imagine the fitment is going to be problematic.
I didn’t check the direction of the liner when installing, but looking at the machining, I may have ended up with a 90 degrees turn, which is worst case for ovality... ::)
Post by: Trigger on February 01, 2020, 03:41:20 PM
You need to get the piston to bore clearance right or it will smoke and burn oil with low compression.
Post by: Erwin83 on February 01, 2020, 06:46:05 PM
Post by: Trigger on February 01, 2020, 10:35:26 PM
Post by: Erwin83 on February 02, 2020, 09:56:18 AM
The piston seems to clean up well.
So, I need a clearance check, (all is standard size now), maybe a hone job and a ring kit.
I wouldn't know why I would bore 4 good cylinders to oversize..?
Post by: Nurse Julie on February 02, 2020, 10:15:16 AM
The cylinder with rust is replaced now, so there is no more rust.It doesn't matter how good or undamaged the cylinders are if they are very close to or beyond spec, they may still need a rebore.
The piston seems to clean up well.
So, I need a clearance check, (all is standard size now), maybe a hone job and a ring kit.
I wouldn't know why I would bore 4 good cylinders to oversize..?
Post by: Bryanj on February 02, 2020, 10:34:03 AM
Post by: Erwin83 on February 02, 2020, 10:44:14 AM
I'm an optimist, so will simply assume it'll work out for me. The clearance check will give all answers.
Post by: Trigger on February 02, 2020, 12:00:00 PM
Sure, this is all basic logics.
I'm an optimist, so will simply assume it'll work out for me. The clearance check will give all answers.
And how are you going to measure the clearance with out buying some very expensive equipment ?
Post by: Erwin83 on February 03, 2020, 10:09:02 AM
[attachimg=1]
Post by: Nurse Julie on February 03, 2020, 10:16:48 AM
(https://uploads.tapatalk-cdn.com/20200203/aff78f7b2707ff6b941545f1810aca6c.jpg)Sent from my I3312 using Tapatalk
Post by: Moorey on February 03, 2020, 10:19:38 AM
Post by: Erwin83 on February 03, 2020, 10:27:25 AM
I did check fitment without having rings installed. The ovality is quite clearly noticeable. In the right direction (IN pointing to inlet port) the piston seems a bit on the loose side in the "new" lining, compared to other linings. If I turn the piston 90 degrees in the bore, it starts to pinch a lot.
The big question will be how big the budget is going to be to get this engine sorted, as I don't have a purpose for this engine now, since I just installed my fresh Big-Bore 466 engine.
If it indeed requires a new piston kit and a re-bore, I will probably shelve it again, but this time in a clean and dry spot.
Post by: Erwin83 on February 03, 2020, 10:29:01 AM
You will get better results using something more flexible
Sent from my I3312 using Tapatalk
Those are again very usable tips.
Did I mention already that I love these forums? So much wisdom is shared ;D
Post by: Bryanj on February 03, 2020, 11:35:18 AM
Post by: royhall on February 04, 2020, 08:04:16 AM
Post by: Bryanj on February 04, 2020, 08:54:47 AM
Post by: Erwin83 on February 10, 2020, 08:57:56 AM
Now I have something to put this engine in, and to make the investments in this engine worthwhile.
Once I make some progress, I'll open a project topic for it.
Post by: Orcade-Ian on February 10, 2020, 11:57:43 AM
I’m a little confused now - you made reference to 400/4 engines once being cheap, so is that a 350 or 400 engine you’ve been bringing back from the dead? The frame you have is certainly 350. No matter really as they both fit the frame anyway. Are you intending building it to standard 350 spec or as a ‘special’ ?
A few of us were (are) a little concerned about your optimism but the worst that can happen is ending up with a ‘smokey joe’ but my mate has Kawasaki triples and I refuse to ride behind him - can’t keep my visor clean!
Anyway, we’re over in Duiven (near Arnhem) in May with the MX-5 folk so if you need any (small to carry) parts, I might have some.
Regards,
Ian
Post by: Erwin83 on February 10, 2020, 02:05:39 PM
No worries. I share your confusion ;D
Let me (try to) shed a light:
I have a very nice CB350f which I own for 16-17 years already. That bike, I converted to a CB400f engine around 10 years ago (cheap engine), which I recently big bored to 466 cc.
Project is here: http://www.sohc.co.uk/index.php/topic,11483.90.html
During my ownership of that bike, I have collected quite a few parts as I bought 2 CB400f's for parts. I sold a lot of stuff that I didn't need, but I still have a cabinet full of stuff and had this engine laying on the ground.
I thought this spare engine was a 400f. It turned out to be a 350f engine (clutch cover should've been a dead give-away...).
Thanks for the offer! If I look out of my window (here in office), I see Duiven just across the river. I'll surely get back to you.
Post by: Erwin83 on February 10, 2020, 02:26:41 PM
First of all, the frame of my CB350f - 466cc has some small damages:
- Exhaust hanger is bent slightly, especially visible with the passenger footpegs down.
- Small holes drilled
- seat hinge is broken off
Since that frame is powder coated, it's not ideal to repair.
Also, the frame is of a CB350f, but the title says 1976, no 350f's were produced in '76.
So step one:
A frame swap.
I will truly have one 'perfect' original '73 CB350f (with a 466 engine though). I'll never sell this one.
Step two:
To build a custom Street tracker themed bike based on the not-perfect frame, with the engine I've started to refurbish in this topic.
This one will be for playing around this summer, and to sell on at some point.
--> hence it makes spending some money on this engine also worthwhile. I'll be going for a cruzin image piston set to prevent the smoking.
I'll open a project for it once I'm on the way.
Post by: Orcade-Ian on February 10, 2020, 03:24:16 PM
Keep us all posted on the progress!
Tot ziens!
Ian