1973 CB350G Canadian Noob Build (Gotta start somewhere!)

Saturdays Wrench

New Member
Hi All :D

I love motorcycles. This is my 4th one and I decided it was time to take on the challenge of rebuilding a bike myself. I am not a mechanic but can be resourceful when I need to be. I love learning. I love wrenching. I respect wisdom. This is why I am posting here, to learn from others, get advice and guidance along the way. I work on a computer from Monday to Friday but just can't wait for Saturday's wrench! 8)

Here's what I'm dealing with:
It's a 1973 CB350G (the one with the front disc brake). I purchased the bike for more than I would like to admit ($1500) and it was not running ( I know, I know..). I justified the price because CB350's are in demand in the area I live in and there are not many around, especially so close to where I live. Also, he gave me a box of parts with it. I was happy. It had been buried deep in his garage for approx 3 years and was starting to get some surface rust and a whole lot of cobwebs. It has approx 33,000 miles (seems a lot but I intend to rebuild the engine), battery was dead, 3 yr old gas in the tank with rust inside the tank, engine turned over, brakes not ceased, tyres almost brand new. I came to the conclusion that the bike was well maintained and decided to go for it.

What I intend to do:
- dismantle entire bike
- recondition all aluminum to mirror shine
- rebuild engine with upgrades
- fresh PC on frame and select parts
- upgraded rims, spokes and tyres
- upgraded front brake, possibly dual disc??
- upgraded suspension in front and rear, stock forks rebuilt, possible inverted forks??
- custom seat, headlight, running/brake light
- clip on bars, upgraded front controls
- brand new wiring harness with Motogadet M-unit & components
- upgraded battery
- redesigned and repainted tank
- upgraded chain and sprockets
- possible upgrade to electronic ignition system
- upgraded rear sets

I'll post more of where I'm currently tomorrow and some pics of the inspiration I have been cultivating. Thanks and sorry again for such a long post, they will be short and more concise in the future.
 

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Saturdays Wrench

New Member
Here is some inspiration pics for now that I have gathered from just doing a little research online. I don't know if I want to go with clip-ons or clubman style. I don't think I will go with a cafe style seat but rather a more bobber style with the end kicked up slightly so it's not like a diving board.

Build progress pics/video to come. In the meantime does anyone have any advice for cleaning/shining the aluminum parts?
I would like the side covers to be nice and clean like BOTs bike (black & orange 350 below).

Thanks!
 

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Tim

Administrator
Staff member
For the side covers, it's just remove them and polish.

BTW I'm in Toronto too. Would like to see some more pics of the rack / bags that seem to be on the bike from the photos. I'd be interested in buying them from you if you're selling.

tim@dotheton.com
 

Saturdays Wrench

New Member
MotoMadness said:
We just finished up one. Let us know if you have any questions or need anything.
Wow it looks awesome man, great job! Thanks for offering up your help, I would for sure love to hear your input when I post some questions. I will hit you up when I get stuck. Off the bat though I know there are 2 common problems with this engine that people have since resolved or figured out ways to combat them/replaced with upgraded parts, I know one has to do with thew Cam chain tensioner or the rollers or something? What is the other common problem with the 350? I read it a while ago but have since forgot where I read it.

Thanks and again great job on the bike, thanks for sharing!
 

Saturdays Wrench

New Member
Tim said:
For the side covers, it's just remove them and polish.

BTW I'm in Toronto too. Would like to see some more pics of the rack / bags that seem to be on the bike from the photos. I'd be interested in buying them from you if you're selling.

tim@dotheton.com
Tim, I sent you an email buddy! Thanks for getting in touch. Part pics coming soon, talk soon.
 

Saturdays Wrench

New Member
Back to the progress! My first teardown session went pretty smoothly. I am learning a lot as I go and just taking my time with it. Again, if you see or read about me doing anything out of the ordinary I would love to hear your feedback. I want to learn as much as possible.

Please excuse the mess in the background of the pictures and video. It's not my house and I don't live there but if it were up to me, 90% of the stuff would be in the junk yard! I'm working with what I have and things are getting done. I plan to organize more over the holidays.

I will be documenting this entire process on YouTube. I plan to even visit/interview some mechanics/builders/fellow riders for input down the road so it should be an interesting series to learn from and I hope you subscribe and follow along with me.

Here is episode 1 of my project:
https://www.youtube.com/watch?v=Gcl8_XqvzHc

Here are some pics:
 

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carnivorous chicken

Active Member
Some interesting stuff, but I'd avoid going for velocity stacks on a street bike, compounded by no rear inner fender as seen in some of those photos. And run a front fender or a brace (unless you want to look at it and not ride it). Just my 2 cents worth...
 

Saturdays Wrench

New Member
Toxic Motorwerks said:
Great start and great videos. Looking forward to more.
Cheers! Plenty more on the way! :D


carnivorous chicken said:
Some interesting stuff, but I'd avoid going for velocity stacks on a street bike, compounded by no rear inner fender as seen in some of those photos. And run a front fender or a brace (unless you want to look at it and not ride it). Just my 2 cents worth...
Thanks Carnivorous, I appreciate the input. Those are photos of another build posted here by different user. Although a cool bike, it was not part of my original inspiration.

Can you explain to me what the deal is with velocity stacks? Mainly for racing or what? Maximum air intake? They look neat, I just don't know much about them.

Thanks again!
 

Saturdays Wrench

New Member
For my second session, I removed the tank, carbs, exhaust, headlight and the electrical harness. The tank is very rusted inside and will need a good wash. In my research I found that vinegar/water and some loose ball bearings or small nuts & bolts with a hefty shake and left for 24hrs is a good cheap way to clean out most of the rust from inside the tank. Can anyone attest? Have any better ideas or recommended products?

While removing the tank I spilled a bunch of gas out of that cross flow tube that's under the tank. Is this just to distribute the gas evenly in the tank? If not what is that for? What if you need to remove your tank on the road and it is full of gas, is there any way of removing the tank without spilling when detaching that cross flow tube or is this normal? The gas sat in the tank for 3 years, so it was pretty smelly. I got a good buzz emptying it though haha..

While I was taking out the harness I was making notes as to where things came and went. I have to admit I a little intimidated before exploring it, but after I took it all apart I realized there's really nothing to it at all and am looking forward to tackling the wiring myself when it comes to it.

Here's the second installment of my Youtube series for the build:
https://www.youtube.com/watch?v=1XSK5_KaGS8
 

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carnivorous chicken

Active Member
Saturdays Wrench said:
Cheers! Plenty more on the way! :D


Thanks Carnivorous, I appreciate the input. Those are photos of another build posted here by different user. Although a cool bike, it was not part of my original inspiration.

Can you explain to me what the deal is with velocity stacks? Mainly for racing or what? Maximum air intake? They look neat, I just don't know much about them.

Thanks again!
Yep, I saw someone else post 'em, but thought a word of caution might be in order anyway. To be honest, I build and ride bikes for the street so my racing expertise is pretty limited -- anyone else is free to chime in here. The danger with velocity stacks on a street bike is that without filters all kinds of crap goes through your carbs and into your engine and increases wear and the chance for failure (and obviously this is compounded by no inner rear fender). They can increase performance, but my understanding is not by much (although when racing, every little bit counts, and you're on a track that doesn't have much road debris and dirt, but bits of tire). And racing bikes go through frequent tear downs and rebuilds. Pods work for some bikes better than others, and stock airboxes are frequently the easiest and best thing to keep a bike running reliably. You're bike has CV carbs, and if you're going to run 'em you're going to want to keep stock air filters. Some folks switch out the carbs for Mikuni racing carbs and run pods, but I've convinced people to go back to stock because they didn't know what they were doing and the stock setup is easier to dial in. On a side note, you'll want to make sure the diaphragms in those carbs aren't ripped -- that's a frequent problem and you won't get your bike to run properly if they are. A lot of people jump in and see bikes with velocity stacks and assume that's what they've got to do, but like I said, it's not a good idea. And a fork brace or front fender is pretty important too; without it forks can twist under pressure.
 
Seasons Greetings,
Good to see another Canadian bike build - after all, DTT started in Canada!
+1 to the fork brace, or at least keep the stock fender mini brace, as those old 33mm forks are not particularly stiff or rigid.
- 1 to velocity stacks on the street unless you like to rebuild your top end on a frequent basis (but look at better flowing filters).
I know a lot of guys like the no rear fender look, but try to get at least a little fender in there to stop crud and water from firing into the back of the motor (maybe paint it flat black or something to blend in). You're riding around Toronto - think about how changeable our weather is.
Like Tim said in a post awhile back, build the bike you want to build and don't worry about the "critics" - the mantras being, make it safe and reliable, enjoy the (fabrication) journey but keep focused on the destination (finish the damned thing).
BTW, love to borrow your rear fender sometime. I want to build a mould to make a fiberglass version, to match up with the 'glass front fender I already build. Your fender will come back a lot shinier than in the photo and still completely usable if you wish to. Can give you a good discount on one of the finished fenders as well - a lot lighter and far easier to modify and / or paint than the stocker.
Have fun with your build.
Pat Cowan,
Vintage Motorcycle Fiberglass / Pacomotorstuff
 
velocity stacks are fine. they can add performance across the whole rpm range on lots of things. unfitered velocity stacks, or ones with little gauze filters in them are not so good on road bikes. all modern bikes have them, but you can't see them because they're hidden in the airbox.

how about a perspex airbox, where you can see the stacks?
 

Saturdays Wrench

New Member
carnivorous, pacomotorstuff, brad black.. Thanks for your input and shedding light on the situation. I will heed all warnings and advice, it is all really helpful. I've seen a few guys add that back fender/blocker for the rear tire and figured it was to protect the carbs/filters so thanks for confirming that. I didn't have plans to build one for my bike but I do now :D I definitely agree with the front fender, I was warned about that early.

pacomotorstuff said:
I know a lot of guys like the no rear fender look, but try to get at least a little fender in there to stop crud and water from firing into the back of the motor (maybe paint it flat black or something to blend in). You're riding around Toronto - think about how changeable our weather is.
Like Tim said in a post awhile back, build the bike you want to build and don't worry about the "critics" - the mantras being, make it safe and reliable, enjoy the (fabrication) journey but keep focused on the destination (finish the damned thing).
BTW, love to borrow your rear fender sometime. I want to build a mould to make a fiberglass version, to match up with the 'glass front fender I already build. Your fender will come back a lot shinier than in the photo and still completely usable if you wish to. Can give you a good discount on one of the finished fenders as well - a lot lighter and far easier to modify and / or paint than the stocker....
great advice man and ya, you can borrow the fender for sure. Send me a private msg or an email and we'll sort out the details.

Thanks again guys.
 

Tim

Administrator
Staff member
So you going to sell me that rear rack or what? :). Seriously would like to buy it as it matches my saddle bags.
 

Saturdays Wrench

New Member
For my 3rd session, I drained the oil, dismantled the front controls and loosened my crankcase covers while the engine was bolted to the frame. I got a little ahead of myself and did not research enough about the oil filter on these bikes. I went looking for a disposable oil filter and only realized there was one built into the engine, staring me in the face after I had done some research and looked at the manual. Good lesson to be learned there.. RTFM... every time. Chalk that one up to an eager rookie mistake.

I ran into a few stripped bolts on the left side of the crankcase, so I could not get to the sprocket to remove it. I've already figured that I am going to drill into them with an 8mm drill bit. That way I can get to the sprocket and remove it so I can move on with the rear wheel. I do not have a chain breaking tool, so it's my only option for now.

No more major surprises with this wrench sesh, was cool poking through the front controls figuring out how they work. I also enjoyed peeking behind some of the crankcase covers at the clutch, stator and what I know now to be the oil filter. I'm looking forward to getting the rear wheel off so I can move on with the teardown.

I removed the old gas from the float bowls in the carbs and saw that they were in pretty great shape when I looked inside. I cleaned them up and sprayed a little WD40 in the bowls, put them back together and sealed them in a ziplock bag for storage.

Check it out:
https://www.youtube.com/watch?v=j8ipiD_a2zI

Here are some pics:
 

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Redliner

New Member
I like what you're doing. You got a good spirit about it, mate.

1. Use PB Blast as a penetrant if you're buying an aerosol. Nothing else! For the really tough stuff like pistons and heavy studs, ATF or ATF thinned with acetone will work. Stuck valves is a different story. It involves making a spark plug into a grease nipple and pumping so much grease into it that it creeps through the valve guides. At least you don't have to take the top off to do it, though.

2. Why do you need a chain breaker? This has a chain with a small clip you remove to split it. The only tool you need is pliers.

3. Don't drill into the case! Just buy an Easy-out bolt extractor. It is a sort of drill bit with reversed threads, so when you are turning anti-clockwise, the threads are digging into the bolt to extract it. Read what size you will need to drill and how deep and for which size extractor. Google.

4. The sad thing is that you've gone too far, but the good news is it's not to hard to put everything back for one important first step; MAKE SURE IT TURNS AND RUNS. I know it sounds like a lot of work, but I can usually take something that's been sitting for a decade and make it run within a day or two, assuming parts are on hand. At least then you can better judge what you need and, more importantly, what you don't.

You took the side cover off. Clean the oil slinger spotless, you don't have to remove it to do so. Make sure the pump screen is clean and not broken or clogged. Clean it. Now put the cover back bone dry with maybe a hair-thin layer of gasket maker, just to avoid a mess and constantly topping it up with oil.

Put oil on, attach a SAFE external test tank for petrol, put the carbs back on without those filters, they're cardboard by now. It's ok to start just for now without a filter, just make sure nothing can get sucked in. Dust is actually gritty and can cause damage inside.

Crack the head bolts one-half turn from the outside inward in a cross pattern, then torque them to spec from the inside ones to the outside ones, working in a cross pattern.

Set your cam-chain tension of you have a manual one. The manual one will have a bolt on the top of the housing.

Set valve clearances.

Set the ignition timing as best ya can after you check that you have spark.

With new plugs, oil, and petrol, give it a go.

Check compression. These will idle with as low as 145psi but you want more than 155, 160 is recommended minimum. The cylinder pressure shouldn't be more than about 5-10psi difference between the two.

Also, GET A MANUAL!!! It is your bible. Check online for anything you're not certain about. Any terms, techniques, or inconsistencies can be cross checked. Don't make a move without consulting SOMETHING.

Watching this build. Like the vids.

Edit:

Just ready over a post again.

The line under the fuel tank is the crossover. It ensures you can use the petrol at the bottom of the tank opposite the petcock side. Some Triumph riders are familiar with tipping their bike to get that last drop of fuel over to the reserve-tap side.

As for disconnecting, there are quick-disconnect solutions that won't spill a drop. Google.

For the rust, do as you're doing now to remove the large rust. Wash it a few times and then fill it to the top with Metal Rescue or Evapo-rust. Glorious stuff. Once you wash it out, if you don't immediately coat it, use some 2-stroke oil mixed with petrol to slosh around and coat the inside, or it will immediately rust. Pics attached of my SL100 in progress. The line is where the Evapo-rust was filled to. I only had a gallon on hand, but when I go over it again it will be evenly cleaned and coated.
 

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Redliner

New Member
Use the impact driver.
If you start to wrestle with a bolt at all, STOP and hit it with the impact before things get very bad. In fact, it might even handle the stripped heads pictured.

Don't be too worries about the order of the bolts in the covers. You will find these listed in a parts fiche such as those on CMSNL.com. All of the bolts are the same on the clutch cover except the two holes with the locating dowels, which are longer.

Here's an SL that say for 15 years and was running the next day! Smoked a little at first but I guess the rings freed up with some ATF. Cleaned and sold 4 days later. Never needed to split the motor! Don't ask about the tank, it's somebody else's hero's journey now. ;D
 

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