Author Topic: 1972 CB 350F - "The Green Hornet" - First Project - Rebuild and Mild Cafe (Read 19788 times)

HondanutRider · « **Reply #25 on:** March 23, 2011, 04:37:39 PM »

Quote from: HondaMan on March 23, 2011, 12:12:57 PM

.... I think Honda did not explain well that the logo on the dipstick ("10w40") was the MINIMUM weight to use in these bikes (the 500/550 suffers the same issue), while the owner's manuals clearly showed 20w50 or straight 30w to be the norm.

HondaMan:

I've a question about your quoted statement regarding Honda's original recommendation for grade of engine oil.

My original Owners Manual for the 1974 CB350F clearly lists the recommended grade "for all temperatures" to be 10W-40. Furthermore they state that single weight oils can be used - above 59F- SAE 30, 32-50F - SAE 20 or 20W, and 32F - SAE 10W. Most riding would probably be above 59 degrees F, so the SAE 30 is acceptable according to their recommendation; but, nowhere does it list 20W50 as the norm.

Is it possible that different locals/climates had different Owners Manuals?

midnightrider · « **Reply #26 on:** March 23, 2011, 11:21:28 PM »

Thanks for the comments and advice, HondaMan. I will let all of you know how my troubleshooting goes - but it will be next week before I do it. I've come this far, so I want to pull the plugs and have them all look similar and desirable.

Quote from: HondanutRider on March 23, 2011, 04:37:39 PM

Quote from: HondaMan on March 23, 2011, 12:12:57 PM
.... I think Honda did not explain well that the logo on the dipstick ("10w40") was the MINIMUM weight to use in these bikes (the 500/550 suffers the same issue), while the owner's manuals clearly showed 20w50 or straight 30w to be the norm.

HondaMan:

I've a question about your quoted statement regarding Honda's original recommendation for grade of engine oil.

My original Owners Manual for the 1974 CB350F clearly lists the recommended grade "for all temperatures" to be 10W-40. Furthermore they state that single weight oils can be used - above 59F- SAE 30, 32-50F - SAE 20 or 20W, and 32F - SAE 10W. Most riding would probably be above 59 degrees F, so the SAE 30 is acceptable according to their recommendation; but, nowhere does it list 20W50 as the norm.

Is it possible that different locals/climates had different Owners Manuals?

My '72 original owners manual says the following:
-------------------
Recommended oil viscosity:
All Temperatures: SAE 10W-40
Temperatures above 59F: SAE 20W-50

Alternate:
Above 59F: SAE30 or 30W
32F - 59F: SAE20 or 20W
Below 32F: SAE10W
--------------------

My chainguard has the orginal dealer sticker from Clearwater Florida

HondanutRider · « **Reply #27 on:** March 24, 2011, 12:23:18 PM »

Interesting differences that you quoted from your Owners Manual. Mine is a 1974 model that was clearly sold here in Toronto Ontario. It has the dealer sticker (McBride) still on the back fender. The "all temperature" recommendation is all that is listed for multigrade oils, and that is the 10W-40. There is no mention of 20W-50, nor any other multigrade.

It also is usually above 59F here in the riding season, but I guess it doesn't stay as hot as Florida.

HondanutRider · « **Reply #28 on:** March 24, 2011, 12:31:33 PM »

Quote from: HondaMan on March 23, 2011, 12:12:57 PM

The cam chains were ALWAYS noisy on these engines, but that is because the rest of the engine is so uncannily quiet. The very first 1972 bikes had hydraulic cam chain tensioners which were (mostly) retrofitted with mechanical ones because the riders who ran 10w40 oils did not make enough hot oil pressure to keep the chains tensioned in city traffic, and the chains wore too quickly from the slack. I think Honda did not explain well that the logo on the dipstick ("10w40") was the MINIMUM weight to use in these bikes (the 500/550 suffers the same issue), while the owner's manuals clearly showed 20w50 or straight 30w to be the norm.

You've done a beautiful job, and I am SO jealous... $:-\$

I still am wondering about what HondaMan described regarding the "hydraulic cam chain tensioners". Is there any more information about this early set-up? I've never come across this point before, but maybe it is described in more detail elsewhere.

hoodellyhoo · « **Reply #29 on:** March 24, 2011, 04:03:30 PM »

Quote from: HondaMan on March 23, 2011, 12:12:57 PM

Those plugs look pretty good for a 350F, actually...but, you might undo the carb castings at the head and install new O-rings inside them. That should help balance out things, as it looks like #2 has a little bit of a vacuum leak (it makes dark plugs, contrary to popular belief). After that, maybe do a vacuum balance on the carbs, because this will cause a change in their balance (if you already balanced them before). And, check that the rubber hoses clamps are good and tight as well while you're at it.

The 350F is sensitive to the smallest of differences because of the shot-glass sized piston bores. So, check each sparkplug cap for resistance, and if they are more than 500 ohms apart on the 1-4 or the 2-3 pair, replace both on that pair. Use the 5k ohm types, and I'd recommend the ND X24ES-U sparkplugs in these bikes for a bit more HP and cleaner plug tips. Don't be afraid to run midgrade gas instead of premium, because the ethanol we are all suffering from causes the burn rate to slow down in these engines, acting as if it were higher octane than it really is. The 350F would run on regular in the day, which is about where mid-grade is now in terms of burn rate.

Make sure all 4 carbs have the same float depth. I don't mean like a Haynes manual says, "within +/- 1mm", but the SAME. Since the intake valves are tiny and the engine is undersquare, tiny differences here matter.

One it is all balanced out, these engines are good to about 12k RPM with a little tweaking. They will run all day at well over 9000 RPM, even pushing a Vetter full fairing!

The cam chains were ALWAYS noisy on these engines, but that is because the rest of the engine is so uncannily quiet. The very first 1972 bikes had hydraulic cam chain tensioners which were (mostly) retrofitted with mechanical ones because the riders who ran 10w40 oils did not make enough hot oil pressure to keep the chains tensioned in city traffic, and the chains wore too quickly from the slack. I think Honda did not explain well that the logo on the dipstick ("10w40") was the MINIMUM weight to use in these bikes (the 500/550 suffers the same issue), while the owner's manuals clearly showed 20w50 or straight 30w to be the norm.

You've done a beautiful job, and I am SO jealous... $:-\$

I gotta write some of this stuff down...

I know you always have said how you would like to own a 350. I'll let you ride mine if you ever come to WI or I go to CO.

HondaMan · « **Reply #30 on:** March 31, 2011, 10:45:19 AM »

Quote from: HondanutRider on March 24, 2011, 12:31:33 PM

Quote from: HondaMan on March 23, 2011, 12:12:57 PM

The cam chains were ALWAYS noisy on these engines, but that is because the rest of the engine is so uncannily quiet. The very first 1972 bikes had hydraulic cam chain tensioners which were (mostly) retrofitted with mechanical ones because the riders who ran 10w40 oils did not make enough hot oil pressure to keep the chains tensioned in city traffic, and the chains wore too quickly from the slack. I think Honda did not explain well that the logo on the dipstick ("10w40") was the MINIMUM weight to use in these bikes (the 500/550 suffers the same issue), while the owner's manuals clearly showed 20w50 or straight 30w to be the norm.

You've done a beautiful job, and I am SO jealous... $:-\$

I still am wondering about what HondaMan described regarding the "hydraulic cam chain tensioners". Is there any more information about this early set-up? I've never come across this point before, but maybe it is described in more detail elsewhere.

The original tensioners looked much like the mechanical one you have now, but with no 6mm bolt/nut on top. There is a port to the main oil galley near the bottom of the mounting hole that fed oil pressure from the galley into the little piston inside the tensioner, which pushed forward to tension the chain. At idle, the pressure was fairly low when the engine was hot, especially with 10w40 oil, so the chain rattled a lot. As soon as the engine was revved to about 2K RPM this noise suddenly quieted.

Two things happened with these tensioners, within 3 months of the bikes appearing: they leaked internally around the piston, lowering the tension force, which let the cam chain slap so much that they wore out the tensioner path parts inside, making chunks of rubber appear in the oil during changes. The bikes were recalled and a new tensioner kit was sent out, which included a tiny ball bearing that was supposed to be tapped into the oil feed hole to prevent pressure leaks at the gasket (hard to do, most seemed to simply disappear instead). On the 1972 bikes made during those first few months of production, an oil port was drilled from the main galley to the lower side of the tensioner's mounting area. They sometimes leaked oil at the new (replacement) tensioners because of the oil pressure, especially if the ball was not installed.

I don't think a lot of these early bikes were made, as I have only seen a few with the characteristic oil leak back there and the retrofit tensioner, which looks slightly different from the regular production version that came out afterward. The retrofit ones were hand-cast, had a sort of sandcast look to them like the early CB750 cases, and the locknut surface was obviously hand-machined, as they were not consistent in their heights. I wish I had some pictures of it all, but it was one of those things that embarrassed Honda, so it was quietly squirreled away...

For sure, the mechanical tensioner is the more desirable part, as the other ones never worked well.

HondanutRider · « **Reply #31 on:** March 31, 2011, 10:53:13 AM »

Thanks for the update HondaMan. (Yer da man

) That's an interesting bit of Honda history trivia.

midnightrider · « **Reply #32 on:** March 31, 2011, 07:34:21 PM »

Wow - I'm glad that my bike was a later '72 model. Thanks for the info, HondaMan!
Thanks so much for all of the help all around...I'm gonna get this thing perfect with all of your help.

So things have been very busy with school, so I haven't got much done. I have replaced the mufflers though, so now i have even exhaust pressure on both sides. It made a noticeable difference in the way the bike responds - quicker response now, especially when transitioning from coasting to accelerating - overall it's running great; smooth, quiet, very peppy.

I've put 900 miles on it now....the head gasket weep is back, so I'm going to re-torque one more time. Then I will re-set everything, re-sync and do another plug chop to reassess my mix...I'll probably get all of that done next weekend.

Also need to re-tighten the steering stem (it gets a very slight wobble when I take my hands off the bars while coasting at 20-30 mph, still stable at speed though....it's a new development - pretty sure it's the reason for the tapered bearing instructions to include re-torquing the stem at 600 miles).

So I've decided to go ahead with a mild cafe, no permanent changes though...seat, clubmans, mirrors, maybe rearsets if they don't require any drilling. I'm gonna shoot for this kind of look:

I know that seat is not going to be found unless I get a lot better at upholstery...maybe this one though:

I still want to get my original seat in shape though...anyone know of a OEM-style seat cover that is quality and affordable?

Thanks for the continued support!

RickB · « **Reply #33 on:** March 31, 2011, 08:49:24 PM »

midnightrider,

That seat on the 350 above is Giuliari cafe seat for a 750. I have one that I bought from Ted at Classic City Cycles for $400 or so. In the end, I felt it was too high for my 350F tank. I sunk the hump down slightly to try and get it to fit the lines better. For the look I was going for, it was still too bulky. It really is meant for a 750, not a 350. It fits great though. The tank, the frame, everything. I'd sell it to you cheap if you're interested, I have no use for it.

If you're interested, PM me and I'll take some photos for you.

Rick.

midnightrider · « **Reply #34 on:** April 01, 2011, 03:31:33 PM »

The bike has been in some ocean breeze, so I figured it need a bath - I cleaned it up and took a few pictures with the new exhaust. It's still gonna be next week or so before I can start on my list of items to do....but here are the pics:

I also just wanted to show you guys this...any Tampa Bay folks ever know of Honda of Clearwater?

midnightrider · « **Reply #35 on:** April 11, 2011, 09:58:37 AM »

Had a good weekend for the bike...

Head gasket weep:
I re-torqued the heads (the 4th time!!) in an attempt to stop the head gasket weep.
Honda manual says 14.5 ft-lbs. Clymer says 14.5 - 16.5 ft-lbs.
At first, I set them at at 14.5 ft-lbs (leak!), then 16.5 ft-lbs (leak!), then 18 ft-lbs (leak!), then I decided to just go outside of spec...20 ft-lbs! annnnnd I have no leak! I've put 70 miles of hard riding since then and no leak at all, so maybe going over spec isn't the end of the world.

After that, I double-check timing. Good! I did notice the spark advancer opens up very quickly though, like as soon as you hit the throttle a bit. Anyone know how it's intended to behave?

Re-synced the carbs. They were off a bit, but I got them all close.

So this baby is running like a champ now! but I haven't done a another plug chop, and the associated further fine tuning...

Also, I forgot to mention where the exhaust came from...
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-exhaust-systems-chrome-cb350f-muffler-001-0411.html
they're Mac and I'm loving them...I'll post a clip next time.

HondaMan · « **Reply #36 on:** April 21, 2011, 11:30:57 PM »

Quote from: midnightrider on April 11, 2011, 09:58:37 AM

Had a good weekend for the bike...

Head gasket weep:
I re-torqued the heads (the 4th time!!) in an attempt to stop the head gasket weep.
Honda manual says 14.5 ft-lbs. Clymer says 14.5 - 16.5 ft-lbs.
At first, I set them at at 14.5 ft-lbs (leak!), then 16.5 ft-lbs (leak!), then 18 ft-lbs (leak!), then I decided to just go outside of spec...20 ft-lbs! annnnnd I have no leak! I've put 70 miles of hard riding since then and no leak at all, so maybe going over spec isn't the end of the world.

After that, I double-check timing. Good! I did notice the spark advancer opens up very quickly though, like as soon as you hit the throttle a bit. Anyone know how it's intended to behave?

Re-synced the carbs. They were off a bit, but I got them all close.

So this baby is running like a champ now! but I haven't done a another plug chop, and the associated further fine tuning...

Also, I forgot to mention where the exhaust came from...
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-exhaust-systems-chrome-cb350f-muffler-001-0411.html
they're Mac and I'm loving them...I'll post a clip next time.

Do you have any leftover parts? I just finally got my first very own 350F last weekend! It needs lots of things...

The spark advancer: the springs may be a little stretched out. The full advance is supposed to happen by 2800 RPM. Since these babes rev so quickly, chances are that it just LOOKS like it is jumping up too fast. If it is advancing full by 1500 RPM, the idle will be hard to get to settle down. In that case, pull off the little springs and cut off 1/2 turn of a loop and re-bend the end, check it again. This situation is very common on the 500/550 bikes, and they often need a whole turn cut off to make them feel right again.

midnightrider · « **Reply #37 on:** May 17, 2011, 01:02:45 PM »

Sorry for the lag...I've been very busy finishing up school and doing research.

Hondaman,
Thanks for the info! I think my advancer is working just fine now that I know that...
I've got an extra advancer, extra point plate, extra set of coils, and....extra taillight assembly. Let me know if you need anything.

I haven't done much more with my bike...still have a slight lean condition across all four cylinders (it's even now). Gonna try putting the needle clip down one notch (so needle up to richen) and see what happens. I also have some 80 main jets I'm going to try out. I'll let you guys know how that goes.

Other than that, I'm doing a mild cafe conversion. I've got clubmans and a leather cafe seat from Dime City Cycles on now...Pictures to be posted soon. Gonna cut the fenders (got extras) and get a new taillight next. Not sure yet if I'm going to put new blinkers on or just leave them off...

Everything I'm doing will be revertible to stock... I'm non-committal and I just can't cut up such a rare bike.

HondaMan · « **Reply #38 on:** May 23, 2011, 05:03:05 PM »

Quote from: midnightrider on May 17, 2011, 01:02:45 PM

Sorry for the lag...I've been very busy finishing up school and doing research.

Hondaman,
Thanks for the info! I think my advancer is working just fine now that I know that...
I've got an extra advancer, extra point plate, extra set of coils, and....extra taillight assembly. Let me know if you need anything.

I'll go look at it tonight!

Quote

Everything I'm doing will be revertible to stock... I'm non-committal and I just can't cut up such a rare bike.

I'd do the same thing (in fact, will...) with the exception of inside my engine.

midnightrider · « **Reply #39 on:** November 17, 2011, 01:40:04 AM »

A few newer pics - a bit more down the stock-cafe road... The bike is now in the hands of good friends while I'm working in Uganda. I put about 1800 miles on it before I left though with a nice trip into GA and down the coast.

Note to those fitting new seats - make sure you have GOOD clearance between the bottom of the seat and the snorkel for the air intake (if you're keeping the stock intake setup) because it can easily change your intake dynamics.

Photo Credit to Debbie Fitch Photography - http://dfitchphotography.zenfolio.com/

fmctm1sw · « **Reply #40 on:** November 17, 2011, 03:58:25 PM »

Hey, welcome back. Last I heard you were in school in Ga. How long are you going to be over there?

midnightrider · « **Reply #41 on:** November 18, 2011, 09:58:37 AM »

Quote from: fmctm1sw on November 17, 2011, 03:58:25 PM

Hey, welcome back. Last I heard you were in school in Ga. How long are you going to be over there?

I'll be here for two years - I'm a Peace Corps Volunteer working as a water/sanitation engineer at a local NGO in the SW near the Rwanda and DRC borders... and I'll be concurrently working on my masters thesis - so I'm staying busy!

The two-wheeled upside is that my org has a number of Honda/Yam/Suzuki 125s/250s that aren't running and I've been given free reign to work on them (anyone got an extra carb jet-cleaning set they want to send to Uganda?) If I ever get a little less busy than I am now I'll start on one of them...

If you're in the Largo/St Pete/Tampa Bay area you might see my bike out on the road - my buddy is keeping it warm for me

I see you've got a 350f down now... sorry to hear that. Got plans for it?

andrewherrold · « **Reply #42 on:** November 18, 2011, 01:11:31 PM »

Hey I noticed you used one of the flex hones on your rebuild. How'd that work out? I have a cb550 with some surface rust on the cylinders. I dont want to bore but just refinish the cylinders so I can go back and use the stock pistons. The flex hones look like a great tool. Any advice?

fmctm1sw · « **Reply #43 on:** November 18, 2011, 06:04:40 PM »

Quote from: midnightrider on November 18, 2011, 09:58:37 AM

Quote from: fmctm1sw on November 17, 2011, 03:58:25 PM
Hey, welcome back. Last I heard you were in school in Ga. How long are you going to be over there?

I'll be here for two years - I'm a Peace Corps Volunteer working as a water/sanitation engineer at a local NGO in the SW near the Rwanda and DRC borders... and I'll be concurrently working on my masters thesis - so I'm staying busy!

The two-wheeled upside is that my org has a number of Honda/Yam/Suzuki 125s/250s that aren't running and I've been given free reign to work on them (anyone got an extra carb jet-cleaning set they want to send to Uganda?) If I ever get a little less busy than I am now I'll start on one of them...

If you're in the Largo/St Pete/Tampa Bay area you might see my bike out on the road - my buddy is keeping it warm for me

I see you've got a 350f down now... sorry to hear that. Got plans for it?

If you want anything mailed, let me know. I don't have a cleaning it of anything though. I'll probably get to the 350F over the winter here. I have a 650 and 550 I'm trying to finish up...

midnightrider · « **Reply #44 on:** November 19, 2011, 01:02:09 AM »

Quote from: fmctm1sw on November 18, 2011, 06:04:40 PM

If you want anything mailed, let me know. I don't have a cleaning it of anything though. I'll probably get to the 350F over the winter here. I have a 650 and 550 I'm trying to finish up...

Man, I appreciate the offer. I was just kiddin' though. You got projects out the a$$, brother!

Quote from: andrewherrold on November 18, 2011, 01:11:31 PM

Hey I noticed you used one of the flex hones on your rebuild. How'd that work out? I have a cb550 with some surface rust on the cylinders. I dont want to bore but just refinish the cylinders so I can go back and use the stock pistons. The flex hones look like a great tool. Any advice?

Well, it worked fine for me - I never had a compression test done after but it was TREMENDOUS improvement. I broke one of the new rings when putting it back on - I just put an old one back on #2 since I couldn't leave the engine open while I waited for a new ring to arrive. It seems to have been fine. My opinion is not professional though. I may ask my friends that are taking car of it to give it a compression test next time they has the testers out.

There are some more pics here that have detail of the rebuild with close-ups of the cylinders:
http://www.facebook.com/album.php?aid=2079109&id=44302334&l=79a631b791

PeteyWash · « **Reply #45 on:** February 19, 2012, 06:12:51 PM »

Hey man. My name's Peter and I recently purchased a '73 350f..... I love it, but it needs a bit of touching up. I really like paint job that you did on this one along with removing the lines on it. I do have a question about the handlebar job that you did on your bike. Did you just flip your bars upside down? The reason I ask is because all my wiring goes through the handlebars and it might be a pain to do all the re-wiring. I have the stock handlebars but think that they are a little high. So.. did you just flip your handlebars down or did you buy new ones?

midnightrider · « **Reply #46 on:** February 19, 2012, 08:31:24 PM »

Hi Peter,
Congrats on your 350F! I love mine (I miss it though, I've moved overseas for a while...)
I bet my brother-in-law in GA may be willing to paint your parts for an affordable price if you're interested...

The bars are aftermarket clubman bars, I had to drill them, mount the controls and pull the wiring through. You have to remove the sheathing to get them through the bends.... I got them (and all of my other custom parts) from Dime City Cycles in Largo (Tampa Bay), they've got tons of great parts and they're great folks.
Check em out at: www.dimecitycycles.com

Cheers,
Jake

hondamatteo · « **Reply #47 on:** February 19, 2012, 11:54:09 PM »

Hi Jake,

Really like that seat you got on there! Fits the bike nicely. Which seat was that from dime city? And how was fitting it onto the bike, difficult?

midnightrider · « **Reply #48 on:** February 20, 2012, 03:03:06 AM »

Quote from: hondamatteo on February 19, 2012, 11:54:09 PM

Hi Jake,

Really like that seat you got on there! Fits the bike nicely. Which seat was that from dime city? And how was fitting it onto the bike, difficult?

My current internet connection barely lets me check my email and post a reply here in basic html... so I can't link to the seat right now.

The fit is pretty easy. You'll need to make some brackets though - they could be welded, bolted, or clamped onto the frame. The frame rails are at an angle in the front as well, so you can make a bracket the "wedges" in between them. The seat has female threaded holes on the bottom rear that you can use to mount to your brackets. I'm living in Uganda now so I can't take any pictures of mine... Alternatively, I think that DCC has a mounting kit that could be useful.

The guys at DCC are really helpful and may have time to give you some advice if you asked. If you email them, tell them that you're looking to mount a seat like the one on Jake Carpenter's bike - and that you saw it here on the forum.

PeteyWash · « **Reply #49 on:** February 20, 2012, 03:54:17 PM »

Thanks a lot man. Yeah I saw the post about you going over to Africa, and I would miss my bike as well. It is as I feared about the bars............ I heard it's a pain in the butt, but I will get some clubmans installed eventually. As far as the paint job, I want to repaint my bike myself but it may not work out due to the fact that I have no garage. If you could either send me your brother-in-law's number or e-mail I would like to at least find out his method to how he went about the paint job. By the way.... your motorcycle is sick.
-Peter

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Author Topic: 1972 CB 350F - "The Green Hornet" - First Project - Rebuild and Mild Cafe (Read 19788 times)

andrewherrold