Topic: 1972 CB 350F - "The Green Hornet" - First Project - Rebuild and Mild Cafe

[midnightrider]

I've been working on this project very slowly for quite a while....I've been planning on starting this thread for about as long as I've been working on it. 
My good friend Jessezm helped me tremendously in his free time when not working on his awesome 77 CB400 Cafe build, so I gotta give him a shout out on my project thread...
His build thread is here: http://forums.sohc4.net/index.php?topic=70938.0 
And here he is:


I'd also like to gives a shout out to Dime City Cycles - awesome guys and they've got just about anything you need....DCC is gonna be my go-to place when I decide to go cafe on this thing.  http://www.dimecitycycles.com/

Backstory:
Picked up the bike a while back...it hadn't ran in about 13 years and had set outside for a while.  With a Clymer, a printed pdf of the Honda Service Manual, and a ton of help from these forums, I rebuilt the carbs, the master cylinder, and petcock, cleaned/coated tank, replaced some of the ignition, corrected some bad wiring, and bought a battery.  I got it running but the carbs were difficult to sync...I rode it a bit but it was rough and then started dieing.

About this time I was preparing to leave my job and move to Tampa for grad school and then (after a year in school) overseas in the Peace Corps.  I decided to bring my project with me to Tampa and try to finish a rebuild and partial restoration so I could ride for a bit before I left for Peace Corps - which is approaching quickly (late summer 2011).  It's ironic that this bike is in Tampa now...I bought it in Warner Robins GA and it had Mass tags (from 98') but the chainguard has the original "Honda of Clearwater" dealer sticker!

I've had very little spare time while taking a full load of grad engineering courses and working as a research assistant, but I've managed to slowly get some work done.  My brother-in-law is going into his family's business of paint supplies and has been looking to learn to paint, so he offered to try matching the candy bacchus olive and repainting the bike.  He did a great job - awesome for his first time painting - and I think that the match is pretty good.  In the meantime, I stripped the bike down, got the frame and odds/ends powdercoated and took to rebuilding the top end.  I actually drove the engine to GA during when going home for the holidays and rebuilt it at Jessezm's house (what a guy, right?).  After getting into the swing of things this semester, I've started reassembling the bike - hoping to finish it during spring break next week (3/14/11 - 3/18/11).

Currently, I've everything except for the engine ready to go; new AllBallz tapered steering bearings are installed, brakes are on and working, all the lights and signals are working...just have to get the engine in and dial everything in (easier said than done, I'm sure).  The only real decision I have left is what mufflers get...

Here are some random pics of the project:

Picked it up and did lots of cleaning:




Needed to make a new fuel pipe when rebuilding the carbs...it was nice to live close to my undergrad and its engineering shop:


Tore it down and left if scattered around my bedroom for a while:




Engine Teardown and Cleaning:


Dingleberry hone!


Buttoned back up with new rings, new gaskets, and a valve job:


New paint - kudos to my bro-in-law:


ZPS Powdercpoating in Largo, FL did a great job:


Mock up with tank and side covers:


And where I am now:


And the engine...just waiting to be put in:


I'll let you all know how it goes...

I'd like input on the following:
 -Which mufflers to choose.  Headers are good and I can cut ot the 2-1 collectors.
 -Whether to powdercoat the header collars or just use electroisys to de-rust.
 -Which break-in method to use...I've been reviewing the extensive colelction of threads with various suggestions.
 -Any other suggestions or comments...


Thanks!

[jsedacca]

Where are you in Tampa? I'm in the west chase area and am rebuilding a cb350f for myself and a cb200 for my gf. Build looks great so far!

[midnightrider]

Where are you in Tampa? I'm in the west chase area and am rebuilding a cb350f for myself and a cb200 for my gf. Build looks great so far!

Glad to hear about another UJM around here!  I've not seen much more than two-tumpers and overpowered crotchrockets.

I'm close to  USF. 
You gonna be done with your bikes soon?
What are you doing for exhaust on the 350F?

[fmctm1sw]

I'm watching.  Your brother in law should post a painting service.  Were those "my" side covers?  Are you going to Daytona?

[jsedacca]

Where are you in Tampa? I'm in the west chase area and am rebuilding a cb350f for myself and a cb200 for my gf. Build looks great so far!

Glad to hear about another UJM around here!  I've not seen much more than two-tumpers and overpowered crotchrockets.

I'm close to  USF. 
You gonna be done with your bikes soon?
What are you doing for exhaust on the 350F?

I just pulled the motor on the cb350f last night. Gonna degrease and POR15 the frame, powder the wheels, polish the fork lowers and reassemble with painted tank/side covers and new seat. The cb200 engine is at dime city cycles and should be done soon to get that started up.

[johnny]

Great start so far! I love to see more 350F's getting a makeover.

[midnightrider]

I'm watching.  Your brother in law should post a painting service.  Were those "my" side covers?  Are you going to Daytona?

He's been mulling over painting...I think he may start doing it more after he moves (this summer).  Actually those are my original side covers...they have parts of the fasteners off of your side covers though!  My brother in law has the side covers...maybe he'll paint them and put them up for sale....he still has some of the candy bacchus olive replica that he matched up and used on my stuff. 

I'm not in Daytona...too much school work... It turns out that grad school is pretty damn hard!

I just pulled the motor on the cb350f last night. Gonna degrease and POR15 the frame, powder the wheels, polish the fork lowers and reassemble with painted tank/side covers and new seat. The cb200 engine is at dime city cycles and should be done soon to get that started up.

Nice! I'll be watching your thread.  I've spoke with a guy from DCC a bit - great dude.  I know they'll do an awesome job on your GF's bike.

[midnightrider]

Making some progress but I've had a few hiccups...
I've got the engine in the frame...I found it's much easier with a few friends.



First of all, I need to get a a better torque wrench (or get a better "feel", which I'm sure comes eventually) - I think that it's over-torquing when set at low torque settings.  It seems like I've stripped to (outter) head cover bolts...they are holding tight though, I just didn't mess with them anymore.  Also broke on oil pan bolt...it seemed to break VERY easily though - and the oil pan is not leaking since I filled her up last night. 

Finally, my dumb arse stripped one of the exhaust studs.  I added a washer and some loctite - gonna go ahead with cranking and replace that later.  I hope it doesn't cause a leak.



I double-checked the carbs before putting them on....everything is to spec.  I've set the static timing, added a bit of marvel mystery oil into each cylinder, and put half a cap of oil into each tappet cover (it's been a while since the rebuild...just wanna make sure it's lubed good up there).  Today I'm putting a final charge on the battery...
Just gotta work out a way to sync the bike without spending much money...thinking about making the manometer described in the Clymer manual.



In this pic you can see that I'm syphoning oil out...I added about 3.5 quarts but it's reading high on the dispstick....is this going to go down after turn the engine over a little bit?
SOLVED: The oil does not enter the filter housing until the oil pump gets it there, so the level dropped back to normal after I cranked it.
     

[fmctm1sw]

It seems like I've stripped to (outter) head cover bolts...  

Been there done that.  I bought a super cheap helicoil set off eBay and it worked fine.  Same one as you, right on the end.  The good news is, it's easy to get at.  Oil pan may be same M6 threads?  That was my first ever helicoil job too.  Complete success....

In this pic you can see that I'm syphoning oil out...I added about 3.5 quarts but it's reading high on the dispstick....is this going to go down after turn the engine over a little bit?

I think the level is going to drop for you a little, yes..

[midnightrider]

Well, it cranked up.  It ran pretty smoothly.  The cam chain is a bit rattly (though the sound is much more pronounced on the video than it is in person).  Timing looked good (just a tad advanced on 2-3)...
BUT
Oil leak!  Definitely from the head gasket...I think that it may be leaking from the bottom as well - it's difficult to tell though.

I know I need to re-torque the head, but is there a chance of this alone stopping the leak?
We will see I suppose...any suggestions are appreciated.

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[midnightrider]

Just got done re-torquing.  The head nuts spun a little, so we'll see if that did it after I re-set the valve clearances tomorrow...

[fmctm1sw]

Just got done re-torquing.  The head nuts spun a little, so we'll see if that did it after I re-set the valve clearances tomorrow...

My '73 has started leaking like a sieve now.  Coming from between the cases too...   

[midnightrider]

The leak slowed considerably after the re-torque; a slow weep now...small enough for me to throw some oil in my bookbag and take it for a ride...

I rode about 35 miles around a rural area; lots of accelerating and decelerating, no lugging, keeping it below 6500 rpm except for a couple 70+ mph short bursts - still below 7000 rpm though.  And it felt great!!!!  I've been waiting so long...


There was no noticeable drop in the oil level after the ride.  I'm going to put another long ride or two in and then try re-torquing the head one more time...the leak is still too much, but I'm not going to open it up yet.  I also don't trust my torque wrench too much, so I'm going to take it to someone with a wrench not from harbor freight!  I know another new head gasket still might be in my future though...

I'll post some pic and video of the fully assembled bike tomorrow. 

Cheers!

[midnightrider]

[midnightrider]

I've done a few more things...

I kept riding it with the weep at the head gasket.  Changed the oil/filter at 100 miles to clean out any shavings and assembly lube...I'm running Honda GN4 10w40 right now, but think I'm gonna switch to 20w50 at the next change to help with the summer heat.   

Last night I re-torqued the head nuts one more time - this time using a torque wrench not from harbor freight!  I torqued to 16 ft-lbs (following the order in the manual, or course).  So far, it seems as if there is no longer an oil weep! 

Additionally, I fine-tuned the carbs on a friend's vacuum gauges - like I thought, they were already very close. 
 
I've clocked 260+ miles now - all sorts of driving including sustained (20+ miles) on the interstate at 60 - 70 mph (last night). The tach is at ~6500 at 65mph and ~7000 at 70, a little lower for both if I lean down low.   

It's running great....typically starts on first/second choked kick when cold, after 10-15 seconds and a few light blips it idles down to 1200 just fine....starts on first kick (and only takes an easy kick) with no choke if it's been ran the same day.  I'm happy with everything all around and I'd be very pleased if it continued to operate as it has, but here are two issues -

1.There is just a tad (very slight) hesitation at ~5500 rpm, which is where I sometimes come into a gear when moderately accelerating (but then it hits about ~5800 and it takes off!). I still haven't been over 8000 in any gear...maybe I'm taking it a little two easy...think I'm going to open it up this weekend.
 
2.The plugs were a little dark (so...rich) when I removed them at re-torque.  Everything is set to spec right now, except for a hole in the left muffler...

Also - I'm going on a trip to visit a friend 250 miles away later this week - it's a straight shot on state highways...I'm debating whether to ride the bike or not....I do want to do long rides on this bike, but can I trust it yet?  Any advice for a long ride?

Thoughts on any of these issues are appreciated!

Also - here are some more pictures of the project if you're interested - I'll let facebook host them
http://www.facebook.com/album.php?aid=2079109&id=44302334&l=79a631b791

[nk140]

Nice looking 350f.  I am hoping mine runs as well as yours and looks half as good.

[HondanutRider]

Nice results from your project!  It looks good and from what you've said, it sounds like the bike is performing well. 

That oil leak is a common occurrence on this model, but it sounds like you have it now under control.  Don't be surprised or worried if it shows up again from time to time.  That likely will happen, but it shouldn't be any cause for concern as long as it doesn't "pour" out.

Your hesitation at 5500rpm may be related to the exhaust set-up you have, but then again may just be the nature of the little four.  They are known to come alive after you hit 7000rpm, and when you run it up through the higher ranges the acceleration really picks up (for a 350 ).  Sounds like you've been breaking-in the rebuilt motor easy and correctly, but I'd continue with that for the first 1000 miles and do an oil change again before running at high speeds for any long distance.  A few short bursts up to red-line might be ok now, and will probably get you to forget about the hesitation lower down.

Running a 250 mile trip on expressways may be a bit much for this machine at this time.  A long time ago (late 1960's ) I used to do just that distance on a 305 Super Hawk.  Although its a smaller machine than the 350 Four, it's about the same size and weight and it actually is a little faster .  I was a bit younger than you, back then, and I recall that those trips were physically a challenge, boring, but still fun after the fact.  Now-a-days, if you want to tackle a similar trip, on a freshly rebuilt machine that is almost 40 years old...well good challenge but be prepared for the unexpected.  I'd wait until you've put 1000 miles at least on the rebuild.  Then you might also be more familiar with the machine and what to expect.

[midnightrider]

Nice looking 350f.  I am hoping mine runs as well as yours and looks half as good.

You can do it!  I didn't know a thing when I started this. Also, I think my brother-in-law will do more painting for a fair price if you're willing to ship parts to GA.  He still has some of the green that he used on mine - I've been waiting to find another candy bacchus olive bike so that I can compare his match job to it.

...Sounds like you've been breaking-in the rebuilt motor easy and correctly, but I'd continue with that for the first 1000 miles and do an oil change again before running at high speeds for any long distance.  A few short bursts up to red-line might be ok now, and will probably get you to forget about the hesitation lower down.

Running a 250 mile trip on expressways may be a bit much for this machine at this time.  A long time ago (late 1960's ) I used to do just that distance on a 305 Super Hawk.  Although its a smaller machine than the 350 Four, it's about the same size and weight and it actually is a little faster .  I was a bit younger than you, back then, and I recall that those trips were physically a challenge, boring, but still fun after the fact.  Now-a-days, if you want to tackle a similar trip, on a freshly rebuilt machine that is almost 40 years old...well good challenge but be prepared for the unexpected.  I'd wait until you've put 1000 miles at least on the rebuild.  Then you might also be more familiar with the machine and what to expect.

Thanks for the comments and advice, HondanutRider!  I really appreciate it.  Do you have any thoughts on the rich condition?  The plugs are just a bit sooty.  Maybe I'll do a plug chop today and post the pictures. 

Your advice on the trip is much appreciated (even if it's not what I wanted to hear!!).  Just for some clarification; I'm not planning on taking the interstate, I'd be on back-roads at 50-60 mph and taking a break every 1.5 hours or so...does that change your advice any? (Or course, I'm fishing for what I want to hear, but what I ultimately appreciate is your honest opinion).  Thanks!

[HondanutRider]

First of all, your "rich" condition may not be that serious, and a slight appearance of blackening on the plugs might be the result of the exhaust condition or they might be caused by timing being slightly off.  After a bit of run-in, you maybe should now re-check your ignition timing and the valve clearances.

That proposed trip on secondary highways would likely be more suitable for your machine.  However, realistically you are going to have to schedule the better part of a whole day to complete one way.  And, you will be tired, even with those rests that are a very good idea.  I still would want to have first completed at least 1000 miles on your newly re-built 39-year old machine on shorter break-in jaunts.  It would be an adventure worth remembering, either way. 

[jaguar]

nice looking bike.
really love the color

[midnightrider]

First of all, your "rich" condition may not be that serious, and a slight appearance of blackening on the plugs might be the result of the exhaust condition or they might be caused by timing being slightly off.  After a bit of run-in, you maybe should now re-check your ignition timing and the valve clearances.

Thanks again, HondanutRider - I know your advice is good.

I re-set the valve clearances 2 night ago - gonna check timing again after the bike cools down enough for me to re-install the plugs (always heard to remove/add bolts or plugs when hot or when cool, but not in transition). 

Did the plug chop at ~6000 rpm
Here are the results, they are placed 1-4 from left to right...I already have some ideas (see below), but would appreciate input




I'm thinking that 2 looks pretty good, maybe a bit dark. 
3 Is definitely dark.....
1 actually looks a little lean, right?
4 seems to be about right to me.

The muffler for 1 and 2 was rusted out and is exhaust taped up right now....so it's more free flowing than the right side.
I have this theory, based somewhat on educated guessing and somewhat on pure speculation:
So 4 seems to be good and it's routed through a good exhaust.  2 and 3 are a little dark (with 3 very dark), so maybe this is an ignition issue since they share a circuit - maybe timing just a bit off (I will recheck tonight or tomorrow).  2 is lighter than 3, and is routed through the more free-flowing muffler, which could also explain 1 being lighter than 4. 
Does this theory make sense? 

I'm an amateur at judging these things, so educated/experienced opinions are appreciated.  I know that I can eliminate some of the guess work by replacing the mufflers....I'm getting there! 

Also - these were not new plugs, Ive ran them since the rebuilt but cleaned them up about 50 miles ago.

[fmctm1sw]

I'm glad it's running well for you.  One thing I always tell people about mine is that they aren't much to look at but boy do they run.  A few things I've done to mine (at similar elevation as you) are:

1:  Used D7EA plugs (both)
2:  Side gapped the plugs (both I think)
3:  Used 72 size main jets (on my '72)
4:  New plug wires (both)

I ran mine right past 10000 RPM one day but I hardly ever ride them like that.

[midnightrider]

I'm glad it's running well for you.  One thing I always tell people about mine is that they aren't much to look at but boy do they run.  A few things I've done to mine (at similar elevation as you) are:

1:  Used D7EA plugs (both)
2:  Side gapped the plugs (both I think)
3:  Used 72 size main jets (on my '72)
4:  New plug wires (both)

I ran mine right past 10000 RPM one day but I hardly ever ride them like that.

Thanks for the advice.  What issues did each of your changes help with? (except for the plug wires, I get that).

Do you think that the bad muffler (and associated reduced back-pressure) could cause 1 and 2 to be lighter, like in my theory?

[VRodPete]

I'm a newbie to the Honda fours (but not to engines in general)... I'd say your plug analysis is spot on - good logic used there. 

I just purchased a '76 550F that's being shipped to me from Cali....  I owned a '77 550F new back in the day, and I have to say I love this forum already. 

[HondaMan]

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...