Got my CL350

tmross

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Picked this 72 CL350 up today. Non running project, motor is free, 99.9% complete. Has been sitting in storage for over 20 years, so its gonna need a complete overhaul. I've already begun tearing it down. Tank has ancient gas sludge residue but looks to be in good shape otherwise. A good bit of rust all over, no where near as bad as my 175, I think it'll clean up decent.

I think I'm going to just go ahead and pull the engine and open it up, clean out the ancient oil slime from the bottom end, inspect the top end.

1st issue I've come across while tearing down is it looks like a rodent made the seat its home at some point, tore up a lot of foam from the inside. I will need to refoam this seat somehow, replace the torn up parts with fresh stiff foam? Any tips on that?

Very excited to finally have a 350, excited to dismantle and clean and learn how it all works.
 
tmross said:
Current status

You didn't waste any time getting it down to the bones :)
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I have a very similar package rack... but it prevents my seat from swinging open.. similar is not the same as exact.
How is your rack supported in the back? Mine has two metal braces that go down to the brake light bracket bolts.
Good luck with your project. It looks very "cleanable".
 
BHSarc said:
I have a very similar package rack... but it prevents my seat from swinging open.. similar is not the same as exact.
How is your rack supported in the back? Mine has two metal braces that go down to the brake light bracket bolts.
Good luck with your project. It looks very "cleanable".
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1 bolt at the shock and 1 at the turn signal, no other support beyond that
 
the chassis is gonna have a nice survivor look, but the engine is quite oxidized and rough looking, there is a place near me that does sand/sodablasting and I'm considering letting them clean it up when I Have the top end apart. Will try my luck with wire brushes first but so many fins and nooks and crannies.
 
The machinist that did my head and cylinders vapor blasted mine and they turned out beautiful and no worries about the media getting in screw holes and such. I ended painting them but I kinda hated too.
 
Does anyone know authoritatively how much fork oil goes in the K4 forks? The service manual I have appears to be for the K0-K3 (?) external spring style forks, and calls for 200cc. I have seen various sources say 125-130cc for the K4, however other sources claim amounts between that and 200cc.

@ancientdad is the factory service manual for the 350 in the VHT database for later models?
 
well I answered my own question, found another manual that seems to cover K0-K5 models.
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I think that 125-150cc number for CL350K4 is a typo though, as it still says 4.2-4.4 oz like the other models. I'm going with 125-130cc.
 
tmross said:
@ancientdad is the factory service manual for the 350 in the VHT database for later models?
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I have not looked through the typical FSM (generally one of the later versions) for a specific year/K series for the fork oil measurement, but this is from the CL350K5 Owner's Manual in our library and should apply to yours.

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Engine is torn down, everything looks really good. Cylinders don't have any scratches but there are some little rough patches, it looks light enough that I'm hoping I can get away with a light hone and new rings. Engine only had 3k miles on it so I really doubt theres much cylinder wear.

Spent a lot of time scrubbing the cases clean, probably not gonna repaint them, I want to retain some of the survivor patina look, don't want to go to clean. I will probably have to have the cylinder and head blasted though cause they're too oxidized and my wire brushes are no match for those fins.

Cam chain tensioner rubber roller was not looking too good, ordered a new one.
 
Question - just replaced the gas cap gasket, is this correct? That metal disk/washer is supposed to just rattle around freely like that on top of the gasket? Feel like thats a recipe for rattle noise, something seems off about that, was not shaking around freely before, but may have just been stuck.

Edit: once again answered my own question, seeing multiple sources saying that metal disk goes inside the gasket.

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Been planning on having the cylinder and head soda blasted, I was able to clean up the cam case and cover pretty well by hand. Wish I could do the same for the cylinder and head but its really tough with those fins.

Anyone have experience with soda blasting? I'm concerned about what kind of finish it will leave, looks like it might be kind of matte? I see people say vapor blasting is preferrable but soda is the only local option for me.
 
The cylinder and head are cast so the surface is very rough. Vapor or soda blasting will not produce a shiny finish. The finish will be matte but clean. I did mine with bead blasting, below is what the finish will look like.
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Well I sucked it up and just went to town with the various abrasives and scrubbers, its aint perfect but It's good enough, and I'm happy theres still a little patina left to match the cases and the rest of the chassis. If soda blaster guy wasn't 30 mins out of town I probably would've just dropped it off with him, but I started getting results by stuffing folded green scouring pads between the fins, and next thing I knew it looked pretty acceptable.

Next step, taking cylinders to machinist for measurement, making sure everythings still in spec, I suspect it is, then a hone and new rings.
 
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Chassis reassembly has commenced, received new steering bearings yesterday so I can start moving forward.

Bottom end is cleaned up and reassembled, new oil seals.

Gonna need to order new tires at some point, probably gonna go with the Heidenau K34s cause, well, there aint much else out there for a 3.00-19. Shame the Duro HF319's don't come in the 350 sizes, I've got those on the CL175 and they've got a good scrambly look about em. And they're dirt cheap too.
 
Guys I've come across something strange, noticed the trip counter knob appears to be on the wrong side of my speedo. Usually they're on the left side of the speedo, pointing outwards, but this one is on the right side, which makes it kind of difficult to access since its crammed in between the speedo and tach. The schematic on cmsnl shows it on the left side, every one I see on ebay has it on the left. Has anyone else seen it on the right side before? The speedo otherwise looks totally OEM, no indication that its a replacement.
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Someone swapped the speedo along the way for a similar model that had a left side tach, could be an earlier CB or CL450 though the parts fiches I just checked don't confirm it. Along the way I've seen a few speedos that were intended for the right side of the pair and had the tripmeter knob on the right but I can't recall the exact model. This shows your gauges and correct orientation. Some of the later models with the metal covers and glass lenses like yours also had blue colored faces as well, but which years and models escape my aging memory. Depends on the stud pattern on the bottom of them, the mounting base plates might swap side to side so the tripmeter knob is on the outside right.

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interesting, so maybe this bike doesn't have only 3700 miles after all. The transmission and shifting components had practically no visible wear so I would've believed it.

Kind of a bummer cause I do use the trip meter a lot (reset it at each fuel up to know when refill).
 
tmross said:
interesting, so maybe this bike doesn't have only 3700 miles after all. The transmission and shifting components had practically no visible wear so I would've believed it.

Kind of a bummer cause I do use the trip meter a lot (reset it at each fuel up to know when refill).
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Mileage on these bikes is really difficult to be sure of unless you have some knowledge of previous ownership. With 5 decades of time past, speedo cables break and it could have been ridden for a while with no speedo movement, crashes happen and used or different-model new parts could have been installed as replacements, etc. I wish I could recall which models had the reversed speedo/tach relationship but the parts fiches now are not always accurate and it would take a lot of research into the individual parts books from our library to answer the question. Check the mounting bases for fitment on the bracket that attaches to the top bridge, if the bolt-up areas aren't side-specific then you could easily reverse them on the bracket. Based on the pictures from the parts fiches, it seems you might be able to reverse their positions on the bracket.
 
yes indeed. might source a correct speedo at some point. the other drama is my headlight bucket broke, at the lip where the ring hooks in. Seems like a common break spot, shame Honda made them out of plastic, the bucket on the 175 is metal. Gotta be honest, got a slight bias towards some of the design decisions on the 175. Not really a whole lot of drastic differences but its the little things that count. Anyway, I repaired the bucket with epoxy, seems to be holding up ok, just gotta be extremely gentle with it. I see some metal aftermarket replacements out there, as another option.
 
tmross said:
yes indeed. might source a correct speedo at some point. the other drama is my headlight bucket broke, at the lip where the ring hooks in. Seems like a common break spot, shame Honda made them out of plastic, the bucket on the 175 is metal. Gotta be honest, got a slight bias towards some of the design decisions on the 175. Not really a whole lot of drastic differences but its the little things that count. Anyway, I repaired the bucket with epoxy, seems to be holding up ok, just gotta be extremely gentle with it. I see some metal aftermarket replacements out there, as another option.
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The ’68 and ‘69 CB and CL 350 had a steel headlight bucket. You could probably find a decent one of those for sale if you want a steel one.
 
well, in light of the realization that this engine likely has higher mileage than originally thought, I'm considering re-splitting the cases and replacing the cam chain. I reused the original chain cause a) thought it only had 3700 miles and b) I replaced the cam chain during the 175 rebuild and found the original chain had barely stretched at all when compared to the new chain. Granted the 175 engine also had unknown mileage, however the shifting mechanism components had much more visible wear, indicating it was most likely not low mileage. On one hand I think the 350 chain most likely has plenty of life left, but on the other hand the engine is already out and on the bench (with no top end yet) and would be so much less work to just do it now that it seems almost worth it for that added insurance.
 
Like your build.

I'm in the process too.

I used a CB bottom engine, cl upper engine and a sl frame. Basically I'm piecing this bike together,

I have a thread going "a long cb/cl/sl350 build"
 
If the cam chain rubber was in bad shape the chain is likely just as old and worth replacing while you are at this stage of the build.
 
boddy said:
If the cam chain rubber was in bad shape the chain is likely just as old and worth replacing while you are at this stage of the build.
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Very good advise.........wish I thought about it when I had mine tore down.
 
yes the tensioner rubbers weren't looking great, they weren't horrible, but I did replace both rollers to be safe. I did remember thinking it was strange they showed much wear at all with only 3700 miles, but now I know...
 
New cam chain arrived and installed, cylinder back from machinist with a hone, bore in spec, got new rings.

In other news I went ahead and snagged a correct speedo on ebay, came with a tach too, $30 for both why not. Looking pretty rough, gonna restore. Both work via drill test.

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well, nevermind that. just destroyed the speedo. opened it up and found a nasty wasp nest, everything completely filthy, mechanism covered in dirt and grease. sprayed a little brake cleaner on it, it got on the odometer number wheels and just melted the numbers and black paint off. looks like absolute **** now. don't see anyway to restore that to look normal.

While I'm frustrated I'll vent that I think it represents an actual design flaw to make these gauges so difficult to open and service. I actually can't think of a legitimate reason why it should be so difficult. Literally every other component on the bike is designed to be disassembled and serviceable, they gauges should've been too.
 
If you do try another go at working on your gauges this is a good video IMO. For the 450 speedo but should be about the same. Done in a very step by step fashion and he discusses the tools he used and made to do the job.


Also this is the lubricant I used and was pleased with it so far.

Amazon.com: Liquid Bearings, The Best 100%-Synthetic Oil to Keep Indoor and Outdoor Locks and Padlocks Operating smoothly, reliably, and Rust-Free!! : Industrial & Scientific

Buy Liquid Bearings, The Best 100%-Synthetic Oil to Keep Indoor and Outdoor Locks and Padlocks Operating smoothly, reliably, and Rust-Free!!: Lubricants & Oils - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
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Hope this helps.
 
Yes I watched that video, very good. I spent the rest of the evening disassembling the speedo all the way, cleaning/lubing all the little parts and gears. Took the odometer apart completely, learned how to reset it back to 000000 heh. Trying to think of a way to repaint those number wheels, I just cant really think of how it wouldnt look stupid.

This was the wasp nest btw

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I suspect that gauge sat with the bulbs removed from it for some time for that to happen. That's pretty ugly.
 
^ yes, the bulb was missing.

Back to engine rebuild, is it necessary to replace the cylinder base o-rings? New ones included with gasket set are not correct size. The originals still seem in good condition and fit securely in the slots. Is oil leaking up past the sleeves really that common of an issue with these bikes? Curious why Honda used o-rings here and not on other bikes (like 175) with same cast iron sleeve/aluminum casing.
 
tmross said:
^ yes, the bulb was missing.

Back to engine rebuild, is it necessary to replace the cylinder base o-rings? New ones included with gasket set are not correct size. The originals still seem in good condition and fit securely in the slots. Is oil leaking up past the sleeves really that common of an issue with these bikes? Curious why Honda used o-rings here and not on other bikes (like 175) with same cast iron sleeve/aluminum casing.
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If the existing o-rings are solidly in place and there was no previous issue (which there rarely is IME) then I'd leave them as is. Wrong o-rings in that spot can certainly cause unnecessary problems.
 
Brainstorming the odometer situation, thought about getting some ultra fine paint pens and retracing the numbers. Problem is the black paint (yes despite being made of black plastic, the wheels were also painted black) bubbled up in some places, so the wheels would need to be sanded/smoothed down, and repainted. The original numbers would be lost and wouldn't be able to retrace them, repainting numbers free-hand would look ridiculous. So I think the touch-up/retrace route is the wrong way here. The other option is decals. I saw some odometer decals offered for various other vehicles, but could not find one for our Hondas, so I made my own and think this just might work. I took pictures of each number and enhanced/edited them together in photoshop. The surface of each wheel is 5x60mm. I have a friend who prints decals so will see if he will help me mock this up.

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tmross said:
Brainstorming the odometer situation, thought about getting some ultra fine paint pens and retracing the numbers. Problem is the black paint (yes despite being made of black plastic, the wheels were also painted black) bubbled up in some places, so the wheels would need to be sanded/smoothed down, and repainted. The original numbers would be lost and wouldn't be able to retrace them, repainting numbers free-hand would look ridiculous. So I think the touch-up/retrace route is the wrong way here. The other option is decals. I saw some odometer decals offered for various other vehicles, but could not find one for our Hondas, so I made my own and think this just might work. I took pictures of each number and enhanced/edited them together in photoshop. The surface of each wheel is 5x60mm. I have a friend who prints decals so will see if he will help me mock this up.
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That's a great idea, and if it works these posts can be a sticky thread in the Parts Restoration, Refinishing and Detailing section.
 
Yes if it comes out good I can print some extras in case anyone else needs one. Realized its technically a sticker, not a decal, cause I'm sticking the whole strip on, not pulling the numbers off individually. Friend isn't equipped to print this so I'll ask around at some local print shops.
 
Debating whether I should have the cylinder/head resurfaced before I reassemble the top end. Ordinarily I'd just roll with it, but when I acquired the bike, there was evidence of leaking head gasket (see pic below). I'm extremely leery of DIY resurfacing after pretty much ruining my DT50 head, it just rounded out the corners. Local machinist resurfaced a warped MB5 head for me last year and that thing was sealed perfect after that. But yeah I've been hesitating to proceed with putting the top end back together cause worst nightmare is getting it running and spotting that dreaded oil leak. I guess thats kind of the essence of engine building, diligence while its apart.

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tmross said:
Debating whether I should have the cylinder/head resurfaced before I reassemble the top end. Ordinarily I'd just roll with it, but when I acquired the bike, there was evidence of leaking head gasket (see pic below). I'm extremely leery of DIY resurfacing after pretty much ruining my DT50 head, it just rounded out the corners. Local machinist resurfaced a warped MB5 head for me last year and that thing was sealed perfect after that. But yeah I've been hesitating to proceed with putting the top end back together cause worst nightmare is getting it running and spotting that dreaded oil leak. I guess thats kind of the essence of engine building, diligence while its apart.
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If you are thinking about it you already know the answer. Think how much you are going to kick yourself if it leaks and you don't!
 
tmross said:
Question - just replaced the gas cap gasket, is this correct? That metal disk/washer is supposed to just rattle around freely like that on top of the gasket? Feel like thats a recipe for rattle noise, something seems off about that, was not shaking around freely before, but may have just been stuck.

Edit: once again answered my own question, seeing multiple sources saying that metal disk goes inside the gasket.

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I didn't see this question answered anywhere. Thank you in advance, how do you get that whole piece out of the gas cap?
Nice restoration!
 
I did end up having the cylinder and head resurfaced. Finally gonna start putting the top end together now and I'm hesitating again on head gasket sealant situation. For the 175 I put head gasket on dry, but with the 350 theres no o-rings around the oil passages and seems like a lot of people copper coat the head gasket and/or put a little hondabond around the oil passages to help it seal better... Thoughts on this? I'm a little paranoid about this head gasket leaking cause it had clearly been leaking when I acquired it.
 
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