Topic: My new to me CB400F

[soonerbillz]

Hi folks!
 So I'll start off by saying I got the bike through a fellow I used to work with.
 The story was the bike was his grandfather's and been sitting a long time. My buddy told me he tried cleaning the carbs but gave up when he couldn't get it to run.
 Now K have it and even though at 50 feet it looked really nice, up close inspection the truth is told. While the odometer shows 17.5k on the bike it seems the majority of its life the bike was well cared for. 
 The engine shows no signs of abuse. It doesn't leak out as far as I can see. The enge kicks thought fine with good compression.  The gears seem to engage and operate properly. That's good.
 While I believe my buddy attempted to breath some life into neglected and sleeping machine he probably just got frustrated with trying get it to start.
 A couple of things he did do saves me some coin.
 First he said when he got the bike that he put new tires and tubes on it. And that's definitely true. They show 0 evidence of any use. That's good.
 He also said the front brake was frozen after trying to fix it he just decided to install a new master cylinder and a new caliper.  That's a good deal for me.
Now the bad.
 I don't believe he actually pulled the carbs or really cleaned them. In fact when I opened the air box the original very dirty air cleaner was still there.  He did or someone did put a aftermarket peacock on the tank. They installed some new plugs but the points cover , just like the carbs looks like it never had been cracked.

 So now the tear down to get the bike really clean and to service and repair the mentioned issues.
 Getting out that battery box was a real pain. Hope it goes back in a lot easier than it came out.
 Looks like the bike also was messed with a bit with a screwed up starter switch and a couple places the wiring was boogered.
Again,  I don't care what the seller says, those carbs were never pulled or cleaned. The pvc hose wasn't connected though.
 The bike is very dirty but now I have it apart enough to start a thorough detailed cleaning.
 The pipes will be removed to deduct and polish.   Tank needs minor rust removal too. Lots of little rubber parts to be replaced. 
 Items ive already purchaed and waiting on:
New starter switch
New chain(the sprockets look good)
All new light bulbs
Air & oil filters
All new cables
New points, condensers, plugs
New coils, wires and caps
Gas cap gasket
Carb gaskets & o rings

I hope to have it back up and running in a couple of weeks.
I'll post pics as I go.
 First a few of the bike when I dragged it home.
 

[MauiK3]

Nice bike, watching!

[soonerbillz]

One of the things I found on inspection was the seat obviously was wrong for the model.
 But it turned out what was done was the original seat pan was recovered and the profile modified.
 I've since bout a new replacement seat. I'll keep the original and may restore it back to oem.

[soonerbillz]

So let the work commence!
As I said many years of dust, dirt and neglect.

[BenelliSEI]

Very worthy of restoration. Following along!

[Kevin]

Welcome to the forum Scott!
Sounds like you are making good progress in short order.

You'll find a lot of good information here, plus a great group of people with years of knowledge.

Have fun with your restoration!

Sent from my SM-S908U1 using Tapatalk

[soonerbillz]

Welcome to the forum Scott!
Sounds like you are making good progress in short order.

You'll find a lot of good information here, plus a great group of people with years of knowledge.

Have fun with your restoration!

Sent from my SM-S908U1 using Tapatalk

Thanks Kevin!
 I've been wrenching on bikes for 50+ years but still learning.  I've had a few Honda of the years but this is my first 400f.

[soonerbillz]

Yeah these carbs were never cleaned properly.
 So I'll split them and replace the rubber parts and the float valves then clean the rest of the brass.
 I have 30 liter sonic cleaner to do the hard work.

[Kevin]

You might want to keep the original float valves. Aftermarket seem to be hit or miss as to whether they will work or not.


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[CycleRanger]

Nice bike. That should clean up well.

[Mark1976]

   That's a great bike and well worth the time effort and money. I've had several over the last 35 years, they're a lotta fun.

[soonerbillz]

You might want to keep the original float valves. Aftermarket seem to be hit or miss as to whether they will work or not.


Sent from my SM-S908U1 using Tapatalk

Well I'll take a good look at them. Thanks for the heads up.

[soonerbillz]

I've spent a good amount of time researching the cam chain adjuster process and issues.
 I've yet to actually mess with it. The bike has 14k or so miles on it.
 Would it be a good idea to just get the manual adjuster and be done with it?
 Of course the bike isn't running yet so I don't know what if and noise it might be making.
 Can I test the horseshoe tensioner and rod before I start the bike to make certain they are moving and free. I know the service guide says the parts have a projected service limit of about 20k miles.

[Mark1976]

   Once you have it running you'll be able to check the cam chain adj better. The adjuster is an issue on   these bikes if they've been neglected (even well maintained ones can be problematic). My current 400f has the updated adjuster in it and the only effective method is to adjust while it is running, you'll literally hear the difference, the chain will go silent. On a stock adjuster that's sticking you'll need to insert a rod or similar device (long thin screwdriver) down the opening for the adjuster shaft and spring and tap on it, then re tighten the set screw. This engine is incredibly quiet at idle when everything is properly set, hence the moniker, "the little sewing machine."

[Don R]

 They are a sweet little bike, like most Hondas they tolerate changes to the exhaust but want the stock airbox system. I restored three, one with pods, it really screamed at half choke. L0L. One was owned by a little lady that was 5 foot nothing tall, she rode it to and up Pikes Peak. It had lowering shocks and the fork tubes were slipped up an inch.
 David Silver Spares restored a boat load of these and had a lot of reproduction parts made but those seem to be running out.
  I rode by a friend's house at red line, a minute later he was at my house buying it. I got it back when he bought a house.

[Mark1976]

   There is so much you can do to this bike, the only limitations are your imagination and depth of wallet, but honestly, its at its best when left stock. Incredibly reliable with great gas mileage, it'll bang right up to 11k and back with nary a complaint. Keep the cam chain adjusted properly and change the oil regularly and they'll run a good long time. I regularly flog mine 4 to 5 times a week...

[soonerbillz]

Finally got the bike stripped down to the extent I wanted so I can do a deep cleaning.  Not pulling the engine or forks. All the parts will now be given a healthy bath and any rust will be removed.
 I ordered a full gasket set and will pull all the engine covers and install the gaskets. Replacing the manifold original and replacing the screws too. Fuel tank is sitting full of derust solution too.
 Really just a lot of detailed cleaning to do and then start the reassembly.

[kap384@telus.net]

Watching closely

[Ellz10]

Finally got the bike stripped down to the extent I wanted so I can do a deep cleaning.  Not pulling the engine or forks. All the parts will now be given a healthy bath and any rust will be removed.
 I ordered a full gasket set and will pull all the engine covers and install the gaskets. Replacing the manifold original and replacing the screws too. Fuel tank is sitting full of derust solution too.
 Really just a lot of detailed cleaning to do and then start the reassembly.

Just my opinion here, and I say this as someone who has spent way too much money on high end gaskets multiple times (sometimes as a result of my own stupidity), I would suggest holding off on taking off the covers and replacing the gaskets until you know 100% that you won't be needing to split the cases. If you replace them now, then end up finding out you've gotta split them, then you're just wasting money on another whole set, ya know?

Just my 2 cents.


Other than that, welcome to the forum and that is an awesome bike! I'd love to get one and do a resto/mod some day!  I'm subscribed to see how this progresses, goodluck!

[soonerbillz]

In the process of cleaning the carbs.
 I have a large ultrasonic cleaner for this. The new kits arrived.
 No doubt that these have never been apart and I can see why the bike wouldn't start. Very dirty, lots of varnish and corrosion from sitting.

 Quite a few of the new parts have arrived so as soon as I get the cleaning done I can start putting the bike back together.
 One thing I found was that when they installed those new tires they put front size tires on both ends 90/90-18.
 So now I have to buy a correct rear size tire.

[soonerbillz]

Though the tires on the bike are obviously brand new I've ordered new tires anyways.
 The ones on the bike are Michelin City Pro and both are marked as FRONT tires.
 Again both are 90/90-18
 I'm sure they are good tires but I like Dunlops so I ordered a correct size set for the bike.
 100/90-18 front
 110/90-18 rear
I ordered the Dunlop 404 types which are good for standard bikes like this one. I'll sell the others to recoup some of the new tire costs.

[soonerbillz]

I know that the 90/90-18 and 100/90-18 are true oem spec tires sizes.
 My choice of using 100/90 front and 110/90 rear is not taken lightly or driven by some vain Mach "bigger is cooler" thought pattern.
 My selection is due to my intended real world use.  I'm not doing a show restoration here. This build is strictly pointed to an every day rider that will see eastern Oklahoma country roads primarily.  The roads here a tough with a lot of less than perfect conditions. Gravel and cracked pavement is common.  Most of the roads have 45 mph speed limits posted for good reason.
 While I understand that the stock 90/90 has better turn in characteristics (I road raced for years and used 90/90 on all my lightweight bikes) the slightly larger sizes I chose will be more than capable plus afford me a better cushion and stability on the harsh road conditions.
I know there is a consensus to what is the recommended tires in these bikes but after 50 years of riding I've found that there is no magic answer that fits every situation and a cookie cuter approach doesn't work well in all cases.
 Opinions are always appreciated.

[soonerbillz]

All day parts cleaning yesterday.
 Lots of hydrosonic and old fashion Dawn & water scrubbing plus my favorite derust solution Evaporust.  Elbow grease and a little bit of determination will get this CB400F  back on the road in a week!
 Today is wheels and frame/frame deep clean.

[soonerbillz]

I haven't done anything in a few days and obviously missed my assembly deadline.
 I found #3 carb had issues and had to order some parts. I also ordered the wrong front sprocket.  I bought a 15T when I should have gotten a 17T. Correct one is on the way.
 Saturday was our group ride and I drove the 73 RD250. It's been so hot here but we made through the day. Temps were up to 105!  Mighty toasty.

[soonerbillz]

My new tires arrived and I will put them on this week.
 I have everything I need to assemble the bike as soon as the carb parts and sprockets arrive.
 The one thing I have to do now is derust the exhaust.
 Unfortunately it is really rusty. I tried to clean it with WD40 and a heavy duty brass brush but the rust in places is so thick it was a waste of time.
 So I've decided to use chemicals in a bathtub soak. I bought an old cast iron full size tub a few years ago and have used it to clean frames with degreaser, soap and water.
 I love Evaporust as you know but at $30 a gallon it's pretty expensive.  Looking around for an alternative I found a product called Rust911. The supplier says its a high concentrate that can be mixed with water. One gallon can make 16 gallons of deruster. At $70 for the gallon container that's a pretty big savings over Evaporust.
 According to the reviews it works just as well when mixed correct.