Honda Twins banner

1 - 20 of 164 Posts

·
Registered
Joined
·
804 Posts
Discussion Starter #1 (Edited)
Hey all, started working on the cb160 I got back when I thought I could repair anything in about a week. Boy was I wrong, funny how youthful confidence works.

Anyway, the bike is a complete basket case, I think every single component needs attention other than the gearbox I believe and head bearings (looking on the bright side). If you need cb160 parts you may want to follow this thread in case I find terrible things in the bottom end. I'm very new to repair so I'm mainly treating it as a learning experience since I've already got the thing, might as well try and see where it gets to. I'll also get an idea of what an engine rebuild is like in case I have the desire to do another one at some point.

Here's a picture of when I first got it, most of the big bits are there. The tank is the wrong colour but came with both metal side bits and one of the rubber bits. I also have a full slightly dented set of exhausts.
CB160.jpg

Engine is siezed so I've got PB blaster in the cylinders and have been doing the rock the bike back and forth in high gear routine and no luck. Took the carbs off and looked in through the carb intakes and the verdict is that it looks nasty enough to make me think taking the engine out of the frame and attempting alternate methods will be quicker and more successful.

One of the carb cables snapped while loosening the adjuster, so I've got a slide siezed in one carb and working on extracting that but at least the bowl finally came off, the drain screw is still stuck though (goes out 2 turns now and stops dead).

Picture of carbs off:
IMG_6731.jpg

Bowl that was stuck on immediately after removal:
IMG_6735.jpg
The corresponding float/rest of carb:
IMG_6737.jpg

Other bowl that has been cleaned and mostly metal rescued
IMG_6736.jpg
Still need to find something to drive out the float pins.

Currently waiting for the weather to be okay to get the engine out and begin the disassembly so I can get the rust out of the cylinders and see what I'm dealing with.

Also, here's a picture of the front sprocket area (looks like it was submersed in mud and oil). The starter cable (closer sheathed wire) is simple to disconnect, but I don't see a simple way to remove the other wiring behind it unless it's just to disconnect all the bullet connectors at the place right before they enter the main wire loom (top left of picture)
IMG_6734.jpg

Advice, comments welcome. I'm sure it will be a very long time before this is anywhere close to anything but a start is a start.

Also disclaimer I have limited knowledge of what I'm doing so take my advice at your own risk etc.
 

·
Premium Member
Joined
·
1,638 Posts
I will be watching this thread. Looks like a nice long project. Taking time to be thorough is well worth it! Luckily the members of this forum are extremely helpful.
 

·
Registered
Joined
·
1,364 Posts
The wire behind the starter cable is the wire loom for the stater and the neutral switch. Pull the left cover and you will see how to remove the wire holder and the bullet connectors. It will all come off with the stater.

Bill
 

·
Registered
Joined
·
751 Posts
For the gunked up carb parts, especially the float pins and stuck slide, heat, patience and pb blaster are your friends. Trying to tap out those pins it's easy to snap one of the towers.

These are fun little bikes, hope to see this one back up and running. I've got some parts (and SL175 sloper parts) so I might chime in if you need something.
 

·
Registered
Joined
·
804 Posts
Discussion Starter #5 (Edited)
Thanks for encouraging words everyone. It stopped raining for a bit today and I got those bullet connectors disconnected so the engine is now all ready to come out.
IMG_6741.jpg
 

·
Registered
Joined
·
804 Posts
Discussion Starter #7 (Edited)
Well I got the float pins out with a hair dryer and some jewelry screwdrivers. That means 1 whole carburetor is completely disassembled.
IMG_6743.jpg

Luckily one of them has been quite decent, the other is being difficult
IMG_6744.JPG
As there are no float bowls available online, looks like the two options are soldering it or putting a screw in with an o-ring to seal it. Any other ideas?
The inside of the bowl is pitted pretty badly as well so the screw idea may not work.

Edit: soldered it shut since I had the iron out repairing a set of heaphones, holds water at least now. The inside is still covered in the white corrosion, need to find a way to get that off since metal rescue didnt seem to have much success (may have been too cold)
 

·
Registered
Joined
·
751 Posts
You can use JB weld for pinhole leaks in float bowls. It holds up pretty well, I've got a bowl that I fixed years ago that is still fine.
 

·
Registered
Joined
·
804 Posts
Discussion Starter #10 (Edited)
I may try the vinegar idea as the pine-sol didn't really touch the oxidation.

From reading these carbs must be "pot metal" (zinc alloy) which explains why this one is so corroded. I think because of that it's important to neutralize any acidic/caustic substances (if not going back into use immediately) you put on these as zinc is sensitive to reaction.

Today's progress: used a heat gun (technically an embossing tool) and got the stuck slide to move up a little bit, sprayed out the newly exposed gunk and will try again later

Also I've heard JB weld works, but I had solder handy and I like that there's no potential (I think) for solder to be dissolved by gas
 

·
Registered
Joined
·
804 Posts
Discussion Starter #11 (Edited)
Engine is out featuring one person specialty engine removal technology
IMG_6751.JPG
IMG_6753.JPG

I'm thinking I may end up needing a new left carb, the current one just doesn't seem like it will function properly. However I guess I'll focus on getting the engine apart and back together before I worry about that.
 

·
Registered
Joined
·
804 Posts
Discussion Starter #12 (Edited)
Finally got the slide out
IMG_6755.JPG
Took the clutch cover off and looks yucky. Hopefully it's just surface rust and oil.
IMG_6757.jpg
Valve cover is off, that one bolt hidden under the mounting bolt is real sneaky. Also unfortunately no master link in sight so will have to cut the cam chain.
As far as I can tell the camshaft looks pretty good as well as the chain, it's a shame I'm going to have to cut it. I will look where the square pan drops out of the lower crankcase to see if the master link is there. Does anyone know why that's there since the oil screen is somewhere else?
IMG_6758.jpg
 

·
Premium Member
Joined
·
1,638 Posts
You can use JB weld for pinhole leaks in float bowls. It holds up pretty well, I've got a bowl that I fixed years ago that is still fine.
My BMW's oil sump is patched together with JB Weld. It is good stuff!
 

·
Registered
Joined
·
804 Posts
Discussion Starter #14 (Edited)
Got the points base plate off, it was quite stuck on the camshaft. Probably to be expected as the points cover is missing and it must have been exposed to the elements. The camshaft oil seal is stuck in the base plate, I'm not 100% sure what is supposed to come out and what is the base plate itself it's so stuck in there.

Now trying to get the rocker arms off, 3 of 4 of the pins are stuck dead, I've been trying to pull them out with vice grips/pb blaster/ some heat but no luck. Seem to be tough metal as they aren't even scratching.

Good to know the JB weld can handle real stuff, I wont hesitate if I end up needing it.

Update: Got them out thanks to the thread called "1971 CB175 Rocker arm removal", the nail tool works well enough that you can get them moving and eventually twist them out with vice grips on the part that sticks out normally.

Now to get the cam chain off, there is not enough slack with the tensioner in (even pulled back completely) to get it to skip teeth and find the master link.
 

·
Registered
Joined
·
804 Posts
Discussion Starter #15 (Edited)
Picked up a chain breaker and separated the cam chain. Dropped half of it down into the crankcase while I was tying the other half onto some string but not too worried since I'll have to split the cases to clean everything out anyway.
I now have a removed head and have to figure out how to remove valves. The one seat is in really good shape, the other is covered in hardened stuff of unknown makeup. Hopefully whatever it is stopped it from rusting under there.

IMG_6772.jpg

IMG_6769.jpg
No wonder the pistons haven't freed up yet. Scraped out as much rust as I could and now letting them soak in pb blaster, I might go see if the tool store has any big sockets on clearance to hammer them out of there with.
 

·
Registered
Joined
·
3,524 Posts
Great project, you are making me want a CB160. I had a couple of them back in the day. The head must be removed before the valve can be removed. Once the cam chain is broke and the head nuts removed it should lift straight up. Use care not to break any of the fins. A rap with a dead blow hammer can break the seal to the cylinder block. You are about to find out what you are up against.
 

·
Registered
Joined
·
1,364 Posts
I use CLR to clean the brass bits and bowls just dont but them in the same container it will turn the brass black. Dont ask how I know that.


Bill
 

·
Registered
Joined
·
1,364 Posts
I have a bowl from a ca 160 that is leaking around a crack in the thread part of the drain screw. I was thinking of melting a wheel weight and pouring it into the slot at the bottom of the bowl.

I dont know what the melting point of the bowl is. Would this work or would heated lead just burn thru the bowl ? I could use JB Weld but was just thinking what if.

Bill
 

·
Registered
Joined
·
208 Posts
80CB400: welcome to the forum. For a small displacement bike, my 160 puts out a very nice howl through a pair of glass-packed megaphones. You'll love the sound too when you get that little beast back together! Great project--keep us informed!
 

·
Registered
Joined
·
804 Posts
Discussion Starter #20 (Edited)
Jim: they seem to be getting quite rare, looks like a good amount have ended up on ebay as parts. The head is off, I think the picture failed to upload properly before.

Bill: I'm not sure, just looking at the melting points on google: lead melts around 100 degrees (celsius/kelvin) lower than zinc, which itself melts at a temperature much lower than aluminum. So if these carbs are pot metal (a majority zinc so it'll be close to the zinc melting point), then keeping the temperature of the lead minimal it should work out. You could likely lose your drain screw function but a permanently sealed one is better than a leaky one.
curmudgeon: Hopefully it'll get to that point and all the engine parts don't require multi-hundred dollar repair. I'm looking forward to that but it's a long way off.

Today's progress: exhaust valves out, intakes are stuck in there, not a great sign. Quite worried about the one valve seat, once I get the head cleaned up a bit more I'll stick it in some metal rescue and see what I get.
I was surprised how easy it was to get the valves out, a socket and a careful firm hammer tap is all it took. Also did a test refit and seemed like I was able to do it with just hand pressure.
IMG_6782.jpg
 
1 - 20 of 164 Posts
Top