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CL350K4 PROJECT - EVALUATION

speely31

Member
Joined
May 30, 2024
Total Posts
29
Total likes
12
Location
Montana
I picked up this 1972 CL350 last weekend. I have been aware of it for about 5 years but because I knew once I started working on a motorcycle I could stop, I just ignored it. Well I couldn't any longer so here goes! Pretty rough for sure but I should be able to turn this into a nice ride!
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So I spent the morning working on this and I have a few questions. Has anyone tried rebuilding the seat pan or should I just replace it?
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Looks like it's complete, so that's a good start in itself. Before going further (and me forgetting to say it), be very careful with removing the headlight from the case. If it's a plastic case (and I believe it is), once you remove the screws lower left and right, don't pull the bottom of the headlight outward very far or you'll crack the top of the case where there's a tab that engages in the headlight rim.
 
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It's odd to me that the hubs, bars, spokes, fenders, and exhaust all look pretty good (chrome stuff), yet the tank and seat pan look pretty rough.

I refurbished my seat pan, but I think an aftermarket replacement or another used pan in better shape would probably have been a better choice for me.

I'll look forward to following along.
 
It's odd to me that the hubs, bars, spokes, fenders, and exhaust all look pretty good (chrome stuff), yet the tank and seat pan look pretty rough.

I refurbished my seat pan, but I think an aftermarket replacement or another used pan in better shape would probably have been a better choice for me.

I'll look forward to following along.
I had same thoughts. I'm glad tho about the chrome parts!
 
I had same thoughts. I'm glad tho about the chrome parts!
For sure. I would say mine was the opposite, but it was just scruffy all the way around. My thread (ongoing) is here and includes some links in the first post to various topics. There are much better build threads than mine, but there could still be useful things there for you. I would definitely recommend checking out the projects and builds section for other 350 threads.

Once the rust is gone, there may not be much left to work with.
@ballbearian may be the resident expert on salvaging rusty CB350's, so if he says that, you may want to research other options for your pan. Here is one option. I also look on eBay frequently for parts, but you might check to see if there is a moto salvage yard in your area. One near me recently closed, but had been a good place to find certain things.
 
For sure. I would say mine was the opposite, but it was just scruffy all the way around. My thread (ongoing) is here and includes some links in the first post to various topics. There are much better build threads than mine, but there could still be useful things there for you. I would definitely recommend checking out the projects and builds section for other 350 threads.


@ballbearian may be the resident expert on salvaging rusty CB350's, so if he says that, you may want to research other options for your pan. Here is one option. I also look on eBay frequently for parts, but you might check to see if there is a moto salvage yard in your area. One near me recently closed, but had been a good place to find certain things.
I may go that route, thanks for the links!
I seen a few Y-tubers that fiber-glassed theirs, I'm not able to decide if this was a good idea or not, I suspect not.
 
Imho, you could try to save that seat pan but honestly I'd look for a replacement. Seats/pans are fairly available for the CL350.
What I find amusing is the plastic manual compartment is still intact.Those are almost always broken.
If the pipes are as good as they look in that photo then you really lucked out.

Be especially careful when you open up the headlight!
The plastic bucket is very fragile and it's very easy to break off a chunk at the top where the headlight ring hooks in and good replacements are hard to find.
That just leaves the gas tank condition.. how does it look inside?
 
Looks like it's complete, so that's a good start in itself. Before going further (and me forgetting to say it), be very careful with removing the headlight from the case. If it's a plastic case (and I believe it is), once you remove the screws lower left and right, don't pull the bottom of the headlight outward very far or you'll crack the top of the case where there's a tab that engages in the headlight rim.
Thanks for the tip, I guess I didn't realize it was plastic.
 
So I removed the engine today and pulled the top end. The engine was not seized but when turned over by hand it would make it to just about TDC and stop. I wasn't sure what I would find. I was guessing something to do with carbon. I found this. Hard to tell from picture but the exhaust valve stem on right bank has so much carbon buildup (then Im assuming swell from moisture over the 25 or so years of sitting outside) that it would allow valve to open! I should probably send this off to a machine shop but instead I'm going to try soaking it and removing it. Then putting head in hot tank at work.

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Should the points cam lobe have more of a lobe on it? The weights are also frozen but I'm assuming I can just soak it and free them up.
What do you think happened to the chain idler? HEAT? Has anyone found a cheaper replacement? Only price I found so far is 180 dollars!
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Look at 4-into-1. I think they have the tensioner for about $50 and the big roller for about $20.

It's tough to judge the points cam. It looks rounded from that angle, but a straight on angle might be more definitive.
 
@ballbearian may be the resident expert on salvaging rusty CB350's,
Don't think I rate that high but a corrosion cowboy from the rusty rodeo for sure. It's missing the 2 large rubber support bumpers in the middle and the lock plunger rod bracket too.
Disassemble and throw in a pan of vinegar to see what solid metal is left. It'll help instruct for hunting another used one and maybe some parts to save.
 
Important to note at this point - the bolt and washer from the advancer unit, particularly the special hardened flat washer, are not common and you don't want to lose them.
 
I have a pretty good idea now what this project needs. So now I have decisions to make- complete restore or just make it rideable?
Ive always wanted to do a complete restore but I'm afraid of what this will cost!
It looks like it wont take much to get engine running, upper gasket set, chain rollers and possibly rings (they are stuck to piston but I should be able to free them)
Will I be okay with aftermarket engine gasket parts?
Carbs are in really good shape, I'm just going to put a kit in them.
Seat and pan replacement for sure.
I should be able to restore gas tank.
I'm guessing fork seals and at least a tear down inspection of swing arm?
I aslo need to look at brakes but Im not to concerned about parts cost.
Then of course all the cables.
Ill tackle guages and lights later, I should have saved this for a winter project!
 
I have a pretty good idea now what this project needs. So now I have decisions to make- complete restore or just make it rideable?
Ive always wanted to do a complete restore but I'm afraid of what this will cost!
It looks like it wont take much to get engine running, upper gasket set, chain rollers and possibly rings (they are stuck to piston but I should be able to free them)
Will I be okay with aftermarket engine gasket parts?
Carbs are in really good shape, I'm just going to put a kit in them.
Seat and pan replacement for sure.
I should be able to restore gas tank.
I'm guessing fork seals and at least a tear down inspection of swing arm?
I aslo need to look at brakes but Im not to concerned about parts cost.
Then of course all the cables.
Ill tackle guages and lights later, I should have saved this for a winter project!
There's nothing wrong with starting with a rideable build then gradually bringing things toward a restoration (while deciding how comprehensive of a restoration you want to do). Full resto can get $$$ quickly. Rideability should be able to be achieved with a modicum of effort and a hodgepodge of parts sourced from the usual suspects. I will say that anything requiring the engine out of frame it's probably best to go ahead and do a real in depth inspection to see what might be better done the expensive way now, rather than pulling the engine again later.

If you're just going rideable, the swingarm removal isn't really necessary, unless you find excessive play in the bushings or it won't take grease, etc. You're going to need a hone with new rings - possibly an overbore - so that might be your litmus test for how far you want to get into it.
 
Aftermarket gaskets are fine if you use Vesrah or NE brand, I've had success with both though the sets will typically be missing some o-rings, happens with all of the aftermarket brands. You should wait for a machinist to inspect and measure the cylinders before ordering rings and/or pistons. Rings that have been stuck in a piston should be replaced IMO, and if it doesn't need a bore then use a piece of broken ring to clean the grooves in the pistons if you don't replace them. Ring grooves have to be completely clean so the rings don't get stuck when fully compressed into the groove. And obviously have a machinist look at the head.
 
Specifically they’re missing (or rather, they come with the wrong size, not worth it IMO to try and fudge it) base cylinder o rings, which are still available from Honda.

The only issue I had with the aftermarket head gaskets is a small oil leak on the right side vertical feed. I used Hondabond (a very small amount) on my current build and haven’t had that problem since.

Don’t be surprised about the rollers, they frequently become trashed from old age.

One note on a comment from way back in this thread, you’re right - Quick-glo seems to have completely disappeared from the market. It’s incredibly sad, as they were a father-daughter shop in Louisiana, who made a great product.

It’s still my go to chrome polish and makes for an excellent combo rust remover/wax for rims, exhausts, etc etc. I’m glad I picked up a few cans, which I’ll now turn into an absolute hoarder over.

edit: oooooook... some google-fu and I can confirm quick-glo won't be back, at least for the forseeable future. For anyone interested there's a news article posted, but I popped it into a new thread here so we don't distract from Speely's build thread.
 
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The only issue I had with the aftermarket head gaskets is a small oil leak on the right side vertical feed. I used Hondabond (a very small amount) on my current build and haven’t had that problem since.
Yes, I should have mentioned that even Honda head gaskets, and almost always aftermarket head gaskets, need a little sealer around certain areas that are known for seepage. And as you mentioned, when done properly it solves the problem without causing any new ones.
 
Once the rust is gone, there may not be much left to work with.
So I started to take seat cover and cushion off to see whats left and it didn't take me long to realize, not much! So I think an entire new seat is in my future.
 
Imho, you could try to save that seat pan but honestly I'd look for a replacement. Seats/pans are fairly available for the CL350.
What I find amusing is the plastic manual compartment is still intact.Those are almost always broken.
If the pipes are as good as they look in that photo then you really lucked out.

Be especially careful when you open up the headlight!
The plastic bucket is very fragile and it's very easy to break off a chunk at the top where the headlight ring hooks in and good replacements are hard to find.
That just leaves the gas tank condition.. how does it look inside?

I'm wondering that myself. I'm waiting for a key that should have arrived in mail today. Looks like Monday.
 
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So I got the key in the mail and was able to open gas door and to my surprise its very clean, I think just some vinegar and maybe a petcock rebuild and it will be good.
The key I ordered from Ebay is another story tho! It kinda works but its for sure not a Honda key, it feels like it could easily bend.
 
There's nothing wrong with starting with a rideable build then gradually bringing things toward a restoration (while deciding how comprehensive of a restoration you want to do). Full resto can get $$$ quickly. Rideability should be able to be achieved with a modicum of effort and a hodgepodge of parts sourced from the usual suspects. I will say that anything requiring the engine out of frame it's probably best to go ahead and do a real in depth inspection to see what might be better done the expensive way now, rather than pulling the engine again later.

If you're just going rideable, the swingarm removal isn't really necessary, unless you find excessive play in the bushings or it won't take grease, etc. You're going to need a hone with new rings - possibly an overbore - so that might be your litmus test for how far you want to get into it.
This is a great idea and I think its the direction I will go. Im going to work first on engine, make it rideable then slowly work on rest. I decided to keep it as original as possible.
 
So I got the key in the mail and was able to open gas door and to my surprise its very clean, I think just some vinegar and maybe a petcock rebuild and it will be good.
The key I ordered from Ebay is another story tho! It kinda works but its for sure not a Honda key, it feels like it could easily bend.
VHT member @12ozPBR has quite a collection of original Honda keys and offers them to members at good prices, you might send him a PM with your key number to see if he has one for you.
 
Aftermarket gaskets are fine if you use Vesrah or NE brand, I've had success with both though the sets will typically be missing some o-rings, happens with all of the aftermarket brands. You should wait for a machinist to inspect and measure the cylinders before ordering rings and/or pistons. Rings that have been stuck in a piston should be replaced IMO, and if it doesn't need a bore then use a piece of broken ring to clean the grooves in the pistons if you don't replace them. Ring grooves have to be completely clean so the rings don't get stuck when fully compressed into the groove. And obviously have a machinist look at the head.
Im assuming I should stick with OE rings then? Im guessing they are still available?
 
So I got the key in the mail and was able to open gas door and to my surprise its very clean, I think just some vinegar and maybe a petcock rebuild and it will be good.
The key I ordered from Ebay is another story tho! It kinda works but its for sure not a Honda key, it feels like it could easily bend.
Well that's odd.
Btw, the gas cap lock can be opened with a screw driver or similar tool. It's not keyed with pins like a regular lock.
 
Well that's odd.
Btw, the gas cap lock can be opened with a screw driver or similar tool. It's not keyed with pins like a regular lock.

I was curious if the gas cap lock actually used keys on different models. I’ve always used a flathead, or even the tip of my house key works.
 
Im assuming I should stick with OE rings then? Im guessing they are still available?
Once you have it apart you'll know if rings and a hone will be enough, and if pistons are necessary then you'll get a set with rings, pins and clips usually. On the off chance that you re-use the existing pistons, you can get a set of standard rings here (provided it hasn't already been bored during a top end job, it does show 10,000 miles). https://www.davidsilverspares.com/part_321946/
 
You mentioned buying kits to rebuild the carbs. That's a reasonable idea for the gaskets and o-rings, but the old brass jets and such are far better than any kit has, and they are rarely too worn to use. Just clean them up carefully and reinstall the brass stuff. If you find they are not original then look for replacements from Keihin, not jets listed as "for Keihin".
 
Once you have it apart you'll know if rings and a hone will be enough, and if pistons are necessary then you'll get a set with rings, pins and clips usually. On the off chance that you re-use the existing pistons, you can get a set of standard rings here (provided it hasn't already been bored during a top end job, it does show 10,000 miles). https://www.davidsilverspares.com/part_321946/
Thanks for the info, I guess it never even occurred to me it could have an oversized piston. Im guessing because these things are air cooled its pretty common even at only 10k miles?
 
Thanks for the info, I guess it never even occurred to me it could have an oversized piston. Im guessing because these things are air cooled its pretty common even at only 10k miles?
I wouldn't say common, but I'd say that 10,000 miles over the course of 50 years, at the hands of who knows how many people, and God knows what their mechanical aptitude was, could easily cause the need for a rebuild. Something as simple as a noob owning it for a few months, not realizing something simple like checking the oil before every ride because it's an air cooled engine that consumes a little bit as a way of life, and then taking it out on a long run where it gets too low on oil and melts down a piston... we've seen it more times than you'd think.
 
Making progress slowly! I truly thought I would have engine assembled this weekend but not even close! I'll save all that for a separate top end assembly post.
In the meantime I was working on freeing up the advance weights! After soaking in a rust remover then WD-40 it wouldn't even budge! At that point I started looking for a new one. We'll a NOS is 350 and used ones on Ebay are 100, without even mention if they work or not.
At this point I figured I had nothing to loose so with a small prybar and a torch in hand I went after it again. Reluctantly it slowly came loose. 1000002484.jpgIt doesn't look pretty but with a little grease it should work fine. I would like to replace the springs but they are NLA
 
A couple thoughts here. The springs might be okay if you use a rust remover and get them rust-free, then if they seem to be stretched you can clip the end loop off one end and bend down the last coil into a new loop. Also, the cam lobe on the advancer needs to be clean, rust-free and polished to a smooth surface with no rust pits or it will wear out the rubbing blocks on the points in a hurry causing the need to re-adjust the points a lot more often.
 
Maybe it's just hard caked dirt and it'll come off in a bath of something to break it down? I had that on my Bomber that had been baking in a dusty barn for 20 years.
 
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