Author Topic: My Dad's 1974 CB450K7 (Read 4456 times)

onepieceatatime · « **on:** March 07, 2020, 01:55:44 AM »

My Dad passed away in May of last year and left me his '74 CB450. He bought it new; Mom and Dad took it on a vacation camping trip to Canada at least once before my sister and I were born. It was the first motorcycle I saw, and he used to give me rides on it when I was little. He last had it on the road in 2014, and parked it after having problems with it only running on one cylinder. I can't remember exactly what he said he thought was wrong with it, but I think he said it was a spark problem. (This would make sense because I found new points and condenser on his work bench.) He never got back to working on it to have it running again.
I drove up to Michigan to pick it up last August, and finally got a chance to start working on it.

There are 5640 miles on the bike.
I started with a little cleaning and polishing, an oil change, and making sure the engine was still free.
It would not quite turn all the way over, so I pulled the spark plugs and looked into the cylinders with an endoscope. Some carbon buildup in the cylinders, and it looked like the intake valve on the left cylinder wasn't closing all the way. I got on ebay and ordered a spare set of front engine mount brackets and built an engine stand adapter.

I put some ATF in the left cylinder with the piston up, and let it sit for a while. I loosened the valve adjuster lock nut and worked the adjuster back and forth a little, and the valve closed as it should.
I adjusted valve clearances.
Even though my Dad was very mechanically inclined, and taught me how to work on vehicles when I was growing up, I remember him telling me that the gentleman who built the bike out of the crate at the dealership is who he always took it to when the valves needed adjusted.
With the valves adjusted, I adjusted the points, and put the engine back into the frame and did a compression test. only 5PSI difference between the cylinders.
I reconnected the carbs and exhaust (with new copper gaskets) and all of the electrical connections.
I put acid into the new battery, and its now on the charger. Once charging is complete, I'll put the battery in and check ignition timing. It will get another oil change also because of the couple of teaspoons of ATF I put into it.
Once ignition timing is set and I get my hands on some ethanol free gas, I'll put the tank back on and try to start it.

Scott S · « **Reply #1 on:** March 07, 2020, 04:17:55 AM »

That's awesome. And it looks to be in good shape, too. I love a "survivor" bike. If it sat that long, you're probably gonna end up pulling and cleaning the carbs.

Man... I want a CB or CL450.

rocket johnny · « **Reply #2 on:** March 07, 2020, 07:01:47 AM »

cool bike and story ! thanx for sharing

Johnie · « **Reply #3 on:** March 07, 2020, 09:13:49 AM »

Yah, neat story there. Cool to have your dad's bike and that it will see the road again. Here is a pic of me back in 1974 when I bought my new CB450.

onepieceatatime · « **Reply #4 on:** March 07, 2020, 02:53:37 PM »

Quote from: Scott S on March 07, 2020, 04:17:55 AM

That's awesome. And it looks to be in good shape, too. I love a "survivor" bike. If it sat that long, you're probably gonna end up pulling and cleaning the carbs.

Man... I want a CB or CL450.

Dad had drained the tank and carbs. I pulled the bowls and jets, they are clean.
I also love a good survivor bike, and plan on only cleaning it up and keeping it mechanically sound. I want it to stay the way Dad always had it.
I'll put new tires on it too, so that I feel comfortable riding it, but it will be a garage queen with only occasional rides.

onepieceatatime · « **Reply #5 on:** March 07, 2020, 02:58:20 PM »

Quote from: Johnie on March 07, 2020, 09:13:49 AM

Yah, neat story there. Cool to have your dad's bike and that it will see the road again. Here is a pic of me back in 1974 when I bought my new CB450.

They sure are good bikes. Thanks for sharing the picture.
I don't know if there are any old pictures of Dad with his, but next time I head up to Michigan, if I can remember, I'll look.

onepieceatatime · « **Reply #6 on:** March 23, 2020, 08:42:46 PM »

Well, I put the new battery in the bike, and set the ignition timing per FSM instructions. I drained the ATF contaminated oil, and put fresh oil in, replaced the brittle fuel line and old tank mount rubber with new, and put the tank on. I cranked the engine several times to try to make sure oil was circulating. Then a bit of ethanol free gas in the tank and tried to start it up.

https://photos.app.goo.gl/zBkA6JeqshJYfL5Y8

I let it idle for a few minutes, and it settled in a little under 2k RPM. The right pipe did heat up a little but was running much cooler than the left.

With that I think I may be back to whatever Dad's original problem was, and time for a little more troubleshooting.

Pielz · « **Reply #7 on:** March 23, 2020, 10:11:28 PM »

Very cool! Excited to see more of this bike

https://www.homedepot.com/p/TruFuel-TruFuel-4-Cycle-Ethanol-Free-Fuel-6527238/203571144

This is what I was talking about when I mentioned getting ethanol free gas at Home Depot. It's only 32 oz and at 6 bucks it's not super cheap per ounce, but good for troubleshooting or test drives if there aren't any ethanol free sources near by!

onepieceatatime · « **Reply #8 on:** March 23, 2020, 10:32:07 PM »

Thanks Pielz.

I found a station in town, I'm not sure when they opened, but all they sell is ethanol free.
I think it was around $2.60 per gallon of 91 octane; I bought 10 gallons.

PeWe · « **Reply #9 on:** March 29, 2020, 12:40:53 AM »

This is a bike to keep as is, let the family history continue

It looks really nice.

If I were you, remove bags and sissy bar for storage to when needed again.

Pielz · « **Reply #10 on:** March 29, 2020, 09:49:40 PM »

Love it! That's killer that you found a place that sells it.

I smelled ethanol free gas and exhaust for the first time not long ago. It was interesting how different it smells. Like a scent time machine. Wonder how leaded gas smelled lol

onepieceatatime · « **Reply #11 on:** March 30, 2020, 04:10:48 AM »

Quote from: PeWe on March 29, 2020, 12:40:53 AM

This is a bike to keep as is, let the family history continue
It looks really nice.

If I were you, remove bags and sissy bar for storage to when needed again.

I definitely plan to keep it as is. Once I have it running properly, I will register it as an antique, and it will be a garage queen, and only come out occasionally. If I have it ready in time, and Rolling Thunder doesn't get canceled, I plan to ride it to Washington DC to participate this year.

PeWe · « **Reply #12 on:** March 30, 2020, 07:24:05 AM »

You have bags for it, why not a happy camper tour on that bike for old times when it runs good?

kap384@telus.net · « **Reply #13 on:** March 30, 2020, 02:31:09 PM »

Awesome bike and great story. Thanks for posting. My '77 750F was my parent's as well! Need to get my K0 on the road.

Stev-o · « **Reply #14 on:** March 31, 2020, 07:06:48 AM »

Nice bike and great story. The bike will forever be a bond between you and your father.

My father was responsible for getting my brother and myself into motorcycles, he bought us bikes when we were young.

onepieceatatime · « **Reply #15 on:** March 31, 2020, 09:42:38 AM »

Quote from: kap384 on March 30, 2020, 02:31:09 PM

Awesome bike and great story. Thanks fo posting. My '77 750F was my parent's as well! Need to get my K0 on the road.

It's nice to have something like a bike that you can use and enjoy to remind you of your parents.
The K0 450s are cool. Always one of my favorites.

I want to get an old 305 Super Hawk at some point too. Dad told me about the one he had while he was in the Navy, and I like the way they look too.
Too many projects for that right now though. I have to get my CB750K7s going first, then the Dream 305 I just bought needs to be picked up and and I have to get it fixed up and running, and possibly a CB750 chopper/rat bike with my spare '75 CB750 engine before I start to think of any more bike projects.

Quote from: Stev-o on March 31, 2020, 07:06:48 AM

Nice bike and great story. The bike will forever be a bond between you and your father.

My father was responsible for getting my brother and myself into motorcycles, he bought us bikes when we were young.

My dad fixed up an old PUCH moped and an old Sno-Burrow for me when I was a kid. The Sno-Burrow was great for running around on the farm. I've been hooked ever since.

onepieceatatime · « **Reply #16 on:** March 31, 2020, 09:45:46 AM »

Quote from: PeWe on March 30, 2020, 07:24:05 AM

You have bags for it, why not a happy camper tour on that bike for old times when it runs good?

I may end up riding it back to Michigan at some point, but the Goldwing is just more comfortable for long trips like that. I don't think Mom has any interest in riding on a motorcycle anymore either, but her and my sister may appreciate seeing it running and being used.

onepieceatatime · « **Reply #17 on:** March 31, 2020, 09:47:16 AM »

I figured I would start with the easy, and put some seafoam in the gas, even though I do not think it is a fuel problem. I let it run for a few minutes, and shut it off. After a couple of hours, I started it up again, and it is still running the same as it was. I think for my next steps, I'm going to measure resistance of the coils and spark plug wires and boots. I'll also double check and clean all electrical connections between the points and coils. Next I'll install the new condenser that Dad bought and see how it runs. Hopefully that will be all it takes, but if not, are there any suggestions on a next step? Perhaps a new spark plug, or synching the carbs? I don't have gauges to do a carb synch, but I guess I need to get some at some point, with all the old Hondas I have.

onepieceatatime · « **Reply #18 on:** April 01, 2020, 09:02:32 AM »

Today I cleaned all electrical connections between the points and coils, and put them back together with a little silicone grease. I installed the new condenser, measured the resistance of the coils and spark plug boots. One of the boots is completely open, infinite resistance. I just got on ebay and ordered a set of NOS boots. I also ordered some new plugs, and a turn signal relay. Once I get those in, I'll try to start it again.

Pielz · « **Reply #19 on:** April 01, 2020, 01:19:09 PM »

Nice!

onepieceatatime · « **Reply #20 on:** April 11, 2020, 05:39:33 PM »

The NOS spark plug boots came in and I installed them, but the little wires inside the boot that hold it to the top of the spark plug were thinner than the originals, and did not grip the spark plug very well. And the new spark plugs did not have the 2 piece screw off top, so I struck out on both of those. Back to the internet to try again. I found that B8ES plugs are "discontinued and replaced by BR8ES", so I ordered 4 of those. I also ordered 2 NGK 8032 spark plug boots. In the mean time I tested the condensers (both old and new) with my capacitor tester (yes, I am an electronics nerd) and they all test fine. I installed the new plugs and boots tonight and started up Dads bike again. It is running on both cylinders, but took off to about 5,000 RPM. I shut it down, and am moving on to the carbs. I don't know much about carbs, I have only really cleaned them, and never had to adjust any. I have the FSM, and a copy of the Honda Carburetor Manual so I guess its time to start learning.

onepieceatatime · « **Reply #21 on:** April 11, 2020, 06:32:49 PM »

Visual inspection solved part of that problem. When I put the tank back on I caused a bend in the throttle cable to the right carb, so with the left carb in idle position, the right was in a partly open position. With that corrected, I started it up again, and idle is between 2,000 and 2,500 RPM. But the right pipe is much cooler than the left again. It seems like I have fuel, air, and spark to the right side if that carb being open is causing the engine to run faster, and the left side as well since that pipe is heating up much more than the right. All of this leads me back to the carbs. I need to get some starting fluid to spray around the carb mount rubbers. I used to have some since I needed it to start the '84 Honda Civic I drove for a while, but can't find any in the garage. I got that car for free and that is about all it was worth, but it got me by for a while. If that doesn't effect anything, then I guess I'll have to start trying to adjust carb settings.

onepieceatatime · « **Reply #22 on:** April 17, 2020, 06:00:54 AM »

Well, I got a day off work, so time to work on motorcycles again. Took care of a couple other things on 2 of the other bikes, and started Dad's bike up again.
That took longer than it should have because the battery was low. It has been on a automatic float charger, so I was puzzled by that. I used a connector that was previously connected to another bike's battery when I installed this battery, and didn't check the fuse holder. Now that the blown fuse is replaced, the charger is doing what it is supposed to.
With the bike running, I sprayed starting fluid all around both carbs, and their rubber mount boots on the intake. No change in RPM at all and idle is still around 2,000 RPM, with the right pipe running cooler than the left.
Since I have very little experience with carbs, can anyone point me in the right direction?
Should I start with the pilot jet on the right carb, double checking that it is clear and clean?
Or start by adjusting the idle speed?
Or some other adjustment?
Thanks!

onepieceatatime · « **Reply #23 on:** April 22, 2020, 06:11:09 AM »

I read through the Honda Motorcycle Carb manual, the carb section of the FSM, and some forum posts on the honda twins forum, along with some input from another member over there. I ran through some carb setup procedures, and still didn't have it running at idle on both cylinders. With what I had learned from my reading, plus what I was observing, I decided to pull the slow jet and clean it on the right cylinder. I didn't see anything noticeable, but ran a guitar string through it followed by a spray of carb cleaner. With the slow jet re-installed it is now running on both cylinders. Next step for me is fine tune timing dynamically, put new tires on it, then insurance and registration.

kap384@telus.net · « **Reply #24 on:** April 22, 2020, 09:17:04 AM »

Good to hear!

Maraakate · « **Reply #25 on:** April 22, 2020, 06:33:16 PM »

Does the bike just have trouble idling? Does it run OK past 2000 rpm if you're taking it up and down the road? I am unfamiliar with this model, but does the 450K7 carbs have pilot jets? I am looking on the parts diagram but I am unsure. If they do have them and if they have o-rings it may be possible that one of the o-rings on the pilot jet is bad and causing an air leak on that cylinder. It may also be the carbs need synchronized.

The bike looks in great shape so I doubt it's one of the following problems but does not hurt to verify:
* Massive air leak on intake side from the spring loaded throttle linkage. If you spray this area, only use penetrating fluid. Do not use aggressive solvents as some of these carbs had felt-like material in this area and this will destroy them; it will also swell up o-rings and cause funny running until the swelling goes away or possibly melt the o-rings.
* Air leak on the choke linkage. Again, penetrating fluid, etc... I've found small air leaks from the choke linkage don't seem to affect much, but depends on the bike.
* Choke plate on one of the carbs is stuck in a certain position. Move the linkage manually by hand and verify this.
* CV piston not moving smoothly.

Incorrect timing can cause funny idling as well. I can't guide you too much on this except get a timing light and read the FSM for the procedure. A test light is also required. I can't tell very well in the parts diagram (or parts numbers) if this is a dual coil setup. If yes, then you can swap the wires and see if the problem moves to the other cylinder then you can narrow down if it is the coil or wires running to that coil.

You mention you do electronics work as well, I do a fair amount of repair on vintage radios, tvs, and arcade equipment and I have ran into plenty of situations where things can test OK on DMM, especially resistance, but then goes haywire when being used in circuit. Especially in HV areas.

Great story and good luck to you!

Maraakate · « **Reply #26 on:** April 22, 2020, 06:39:05 PM »

Also, I see you're two counties over from me. I'm in Lancaster County. If you get stuck and want a second set of eyes I can stop by sometime. I have PPE; but can wait until things tide over too. Send me a PM if interested.

onepieceatatime · « **Reply #27 on:** April 23, 2020, 04:57:45 AM »

Quote from: Maraakate on April 22, 2020, 06:33:16 PM

Does the bike just have trouble idling? Does it run OK past 2000 rpm if you're taking it up and down the road? I am unfamiliar with this model, but does the 450K7 carbs have pilot jets? I am looking on the parts diagram but I am unsure. If they do have them and if they have o-rings it may be possible that one of the o-rings on the pilot jet is bad and causing an air leak on that cylinder. It may also be the carbs need synchronized.

It was just having trouble at idle. I haven't taken it out on the road yet, but up over about 2500 RPM it was running on both cylinders, below that only the left. I accidentally figured that out by putting the tank back on and causing a bend in the throttle cable to the right carb. At the higher RPM this caused, both pipes got hot. I ended up cleaning the slow jet on the right carb and it now runs on both at idle. There is a pilot screw, and I pulled both to make sure they were clean, and the washers and o-rings intact, as well as the left side slow jet just for good measure.
This bike has CV carbs, and no vacuum port for sync gauges, so it is pretty much all careful adjustments to get it right. A member on the Honda Twins forum gave me a checklist for how to accomplish this, and I feel confident that I did it correctly.

Quote from: Maraakate on April 22, 2020, 06:33:16 PM

The bike looks in great shape so I doubt it's one of the following problems but does not hurt to verify:
* Massive air leak on intake side from the spring loaded throttle linkage. If you spray this area, only use penetrating fluid. Do not use aggressive solvents as some of these carbs had felt-like material in this area and this will destroy them; it will also swell up o-rings and cause funny running until the swelling goes away or possibly melt the o-rings.
* Air leak on the choke linkage. Again, penetrating fluid, etc... I've found small air leaks from the choke linkage don't seem to affect much, but depends on the bike.
* Choke plate on one of the carbs is stuck in a certain position. Move the linkage manually by hand and verify this.
* CV piston not moving smoothly.

Good to know about the penetrating fluid only.
I was concerned about the CV piston, but was not ready to pull that apart yet, and I am glad i didn't since it looks like it was just the slow jet blockage.

Quote from: Maraakate on April 22, 2020, 06:33:16 PM

Incorrect timing can cause funny idling as well. I can't guide you too much on this except get a timing light and read the FSM for the procedure. A test light is also required. I can't tell very well in the parts diagram (or parts numbers) if this is a dual coil setup. If yes, then you can swap the wires and see if the problem moves to the other cylinder then you can narrow down if it is the coil or wires running to that coil.

You mention you do electronics work as well, I do a fair amount of repair on vintage radios, tvs, and arcade equipment and I have ran into plenty of situations where things can test OK on DMM, especially resistance, but then goes haywire when being used in circuit. Especially in HV areas.

Great story and good luck to you!

I had set the timing statically, before trying to start it up. I do have a timing light, and dynamic timing is off a little bit. When I get a chance to work on it again, I will make adjustments there to fine tune it.
Yep, dual coil setup, and good point about resistance at high voltages. I haven't done much with vintage radios or TVs in recent years, but used to tinker with them quite a bit. There is actually an old floor model black and white TV sitting the garage, that I was thinking about getting rid of, since it has been there so long, and I haven't even tried to see if it works. I recently acquired an old (Pinball Wizard) pinball machine that works with the exception of some of the lights, so that is on the to do list too.

onepieceatatime · « **Reply #28 on:** April 23, 2020, 05:04:14 AM »

Quote from: Maraakate on April 22, 2020, 06:39:05 PM

Also, I see you're two counties over from me. I'm in Lancaster County. If you get stuck and want a second set of eyes I can stop by sometime. I have PPE; but can wait until things tide over too. Send me a PM if interested.

I appreciate the offer, but think I have it sorted out now. If you want to get together for a ride sometime that would be great. Also, if you are in need of, or want some old (I think some as old as the 40s) electronics test equipment, I have some that is looking for a good home.

Maraakate · « **Reply #29 on:** April 23, 2020, 02:57:58 PM »

Okay, sounds like you basically have it dialed in now at this point. I forget off the top of my head, but I know a local Honda Dream guy who knows how to do a sync of those older carbs without requiring the gauge. I remember it involved chasing an idle. If you want I can get the information from him.

I may be interested in the test equipment. Mostly looking for HV probes (especially ones that are more accurate around 5KV). Send me a PM with what you have and we can sort that out.

onepieceatatime · « **Reply #30 on:** April 23, 2020, 06:35:21 PM »

Quote from: Maraakate on April 23, 2020, 02:57:58 PM

Okay, sounds like you basically have it dialed in now at this point. I forget off the top of my head, but I know a local Honda Dream guy who knows how to do a sync of those older carbs without requiring the gauge. I remember it involved chasing an idle. If you want I can get the information from him.

I may be interested in the test equipment. Mostly looking for HV probes (especially ones that are more accurate around 5KV). Send me a PM with what you have and we can sort that out.

You got it, set the idle low, but keep both carbs balanced, then adjust one pilot screw a little at a time until it doesn't gain more RPM, then turn it back a little, set the idle low again, keeping both balanced and adjust other pilot screw the same way, then set idle where it is supposed to be.
If that is how a dream is done, then I have it in my future again, as I bought a 305 dream project that I can't go pick up until Army lifts travel restrictions. It is at a friend's brother in law's house, since he was kind enough to pick it up from the seller in the town he lives in and store it until I can get it.

I'll get a list of equipment together tomorrow, if I get a chance, and send you a PM.

Pielz · « **Reply #31 on:** April 23, 2020, 07:00:02 PM »

Honda dreams are incredibly cool! I'll be excited to hear about it when you start messing with it

Sent from my LG-G710 using Tapatalk

onepieceatatime · « **Reply #32 on:** April 27, 2020, 12:01:46 PM »

Quote from: Pielz on April 23, 2020, 07:00:02 PM

Honda dreams are incredibly cool! I'll be excited to hear about it when you start messing with it

Sent from my LG-G710 using Tapatalk

At least one of the CB750s (maybe both) will be before the dream, on the list of projects, but here is a picture.

News:

Author Topic: My Dad's 1974 CB450K7 (Read 4456 times)