Topic: Came across 1974 cb 750 that is near mint, sitting 30 yrs

[BeSeeingYou]

Try the Evapo Rust or Prep and Etch.  I think they are the same thing.  Phosphoric acid.  It does not damage the paint if you wipe off any spills but it's not that hard to be neat and not slop stuff around.   Give it a coat of wax before you start.  Remove the petcock.  The upside to using those is they leave a protective coating that stops flash rust.  You need to clean out any gas varnish as the acid will not remove that.  This may be the hardest thing to get out as you will be limited to less effective methods as the others, acetone, paint stripper, lacquer thinner, carb cleaner will damage the paint easily.

 Vinegar to remove the corrosion is a safe alternative but takes a few days.

 Pull off a carb bowl and see what you have there.  Might be a mess or maybe not.  It really depends on whether the petcock was on or off during storage.  I got my F1 after 25 years of storage and it just needed carb bowls wiped clean and one idle jet unplugged, tank cleaned out,  and a brake rebuild.  Fired right up and has been running without issues for 4 years. 

[Scott S]

 Yeah...if you don't buy that for a grand, I will personally fly up to Chicago and kick your butt.

 That's an amazing bike. Looks well cared for.

[Johnie]

One more bit of info. Refrain from pulling in the front brake handle. There is a good chance if you do that you will freeze the front pads to the disc and you will not be able to move the bike. Possibly someone already did that, so bring along a large rubber mallet. If the front frake caliper is stuck give the side of the caliper a couple wacks with the rubber mallet. It should free it up enough to move it.

[MCRider]

One more bit of info. Refrain from pulling in the front brake handle. There is a good chance if you do that you will freeze the front pads to the disc and you will not be able to move the bike. Possibly someone already did that, so bring along a large rubber mallet. If the front frake caliper is stuck give the side of the caliper a couple wacks with the rubber mallet. It should free it up enough to move it.

Good point. And while on brakes, there have been several posters lately saying their rear brakes shoes have delaminated from age. Once applied at speed, they came apart in the hub. I'd say even if they look good, I'd replace the rear shoes.

[Sniper X]

It will probably be alright if you follow the other posters advice and do the tank, carbs, and make sure the plugs are clean and the change the oil before even trying to fire it off. Good luck! Might just turn out to be a total find after you get it sorted out!

[Trevdawg]

I will totally change the plugs and oil.
A for the breaks, if it sticks and then I losen it. Will it get better as I use it more or continue to stick, for up front?

For the rear drum. My current bike has disc which i am more familier with. Are drums easy to work with, are they very bad in breaking compared to disc or not a Hugh difference?

[MCRider]

I will totally change the plugs and oil.
A for the breaks, if it sticks and then I losen it. Will it get better as I use it more or continue to stick, for up front?

For the rear drum. My current bike has disc which i am more familier with. Are drums easy to work with, are they very bad in breaking compared to disc or not a Hugh difference?

Front: if its sticky now, likely only a cleaning will really fix it. You get corrosion in the caliper (age) and old gummy fluid that gums everything up. (age)

Rear: easy enough. requires pulling the wheel though. A proper working one does its job fine. From the pictures I've seen on the forum, you don't want those shoes coming apart on you at speed.

In both cases these are age issues, not necessarily that they are worn out.

[Trevdawg]

Would it matter if I used standard oil vs synthetic?

[MCRider]

Would it matter if I used standard oil vs synthetic?

Oh you must be kidding! Where's the popcorn?

Oh i see you are fairly new. An "oil thread" as you are attempting to start, is one of the most controversial subjects on a motorhead forum, bringing us the closest to cyber blows that can be had.

For my money, any oil labeled "for 4 stroke motorcycles" is fine 20W-50 unless you're running in the cold.

Having said that, I will hasten to duckout.   

[Johnie]

Yah, some guys have tried synthetic and more oil leaks occur. Some guys like it. This bike was designed before the synthetics came about. I would stick with what MC said and will now bow out of the oil thread too. 

[Hinomaru]

Welcome to the forums and great advice from the others! 

I bought one of those 6000 mile wonders back in 2006, a freedom green 750 K4 just like yours also with the original tires. For some reason mine had the wrong tank emblems, LOL. It was stored indoors, but neglected for 25 years or so. My biggest problem and PITA was the front brake as it needed a 100% rebuild. The master cylinder and caliper were rebuilt, new OEM rubber lines & metal pipe were replaced along with new OEM brake pads. I also had the front rotor surface ground for good measure. Problem was that the brake now worked too good as it taxed the original sagging fork springs. I ended up replacing the old springs along with new fork seals and fresh fork oil. After all that time and money spent, the brake and suspension was working showroom fresh once again.

The day it was purchased and brought home:

[MCRider]

Very nice Hinomaru!

[Johnie]

Dang Hinomaru...that is gorgeous!!! And how can it look so good on the day you got it home. Not to highjack, but do you have any pics of it now to post? And what lift do you have and do you like it? I am in the market for one.

[CrankyOldGuy]

Great find.  I enjoy reading about young people who get introduced to the CB sohc's ... hook, line and sinker so to speak.

Call me weird but I just enjoy walking by and looking at my 750K1 every day.  It hasn't run in 36 years but it sure brings back memories.  I may not be as ambitious as some but I have a basement full of parts I have been collecting over the past 2 years.  I will not say how much I have spent ... cause the Mrs. may read this post 

Harry O.

Harry O.

[Hinomaru]

Thanks guys!

Johnie, I suspect my K4 was professionally detailed before being put on the market. Since it was originally purchased & titled to a corporation back in 1974 and not an individual, there wasn't any past history, old employees, records, stories or anything else for me to go on. Just the bike, as found. The corporate lawyer who signed the title over to me was younger than the bike by a couple years, LOL. The shop where that photo was taken no longer exists and I don’t remember the lift brand, but it was foot valve / air operated from a compressor. No recent pictures of that K4 on this laptop, will have to take some when I return to San Diego in about 6 weeks where the bike resides. Current look is a copy or replica of the 1974 English / UK market model style in planet blue, identical to the example below. Yes, I set aside the original freedom green paint and other correct parts when doing this makeover.

[Hinomaru]

Trevdawg,

Sorry for the earlier thread hijack, sometimes that happens around here.  

Congrats on your bike! Before I forget, I would suggest taking the time to read the owners manual that you found under the seat. You will find all kinds of info specific to your K4 that can’t easily be found anywhere else. Should really help in getting to know your "new" bike as it will answer many of your questions. Believe it or not, I find myself referencing my K4 owners manual when I have a senior moment. 

   

[harisuluv]

Ummm that is an absolute steal at $1000.  As has been said already, bikes like that are not around anymore, and for sure not at that price.  You got a good one, congrats.

[Trevdawg]

Ok ok. I will keep it regular oil.... Good point that synthetic really wasn't around when the bike was made. Tomorrow is the big day!!!
Thanks everyone for the advice and the excitement for finding this deal. I'm just glad I found this sight otherwise I would really be in the dark.

Another question that came to mind. Maybe it is some where else but..
I'm afraid to even wash this thing because I dont want those original stickers to come off.  Maybe I will go over it with a damp rag and then wax it.

I will have a large update tomorrow afternoon/ night.

[Stev-o]

If it's been stored inside and is just dusty, a damp rag will be fine. I never hose mine down.  For the real greasy areas, Gunk Foamy Engine cleaner or Simple Green works great. 

[Scott S]

A for the breaks, if it sticks and then I losen it. Will it get better as I use it more or continue to stick, for up front?

For the rear drum. My current bike has disc which i am more familier with. Are drums easy to work with, are they very bad in breaking compared to disc or not a Hugh difference?

 If it sticks, rebuild it. While not 100% "correct", I'd spring for braided steel lines up front, too.

 The rear works well when set up properly. Use good pads, front and rear. I like EBC but there are others, too. Maybe sand the friction surface of the drum with some fairly heavy grit sandpaper.

[ChuckG750f1]

If it's been stored inside and is just dusty, a damp rag will be fine. I never hose mine down.  For the real greasy areas, Gunk Foamy Engine cleaner or Simple Green works great.

I use windex for quick clean up (my wife can never find the windex).  My '76 has all the stickers and it doesn't damage them.  Today is like Christmas for you and we're all a little jealous and at the same time happy to know they're still out there waiting to be found!  Enjoy!

[James T Kirk]

i too found a time capsule. '79 CB750 Ltd., 2632 mi.

i've since put on another 800 miles on it and lemme tell ya, things that should be worn out, wear out! i think i've gone through all the systems now and should be good to go. but i still worry a lot during the long ride away from home. dunno how much of this applies to SOHC Hondas but this is what i've done:

carbs: disassemble and clean everything thoroughly. had to rebuild leaky petcock.

ignition: pulsers fail when bike is warm, replaced. new spark plugs/wires. one coil had a crack in it from sitting so long. replaced with Dyna coils.

charging: replaced rotor and reg/rec.

tires: had the originals on it. replaced with rubber from this century.

brakes: disassembled front caliper, cleaned thoroughly.

get a factory service manual. read tons of posts on this forum about everything. and be ready to troubleshoot.

Kirk Out

[Trevdawg]

What is the difference between the
Cb750F
Cb750K??
Since I am going to buy some parts I noticed there can be a diffference of oil filters between these bikes.  Other then that, the plugs, air filter, etc. appear to be the same

[Trevdawg]

Thanks kirk

[ChuckG750f1]

What is the difference between the
Cb750F
Cb750K??
Since I am going to buy some parts I noticed there can be a diffference of oil filters between these bikes.  Other then that, the plugs, air filter, etc. appear to be the same

The first 750 f0 is 1975. The f bikes are distinguished from the k bikes by style of the tank, seat/rear pod, lack of chrome rear fender, headlight mount, no gaitors.  Performance wise they use a rear disk brake, 4-1 exhaust, higher compression and different gearing.  The frame geometry is also different.  I'm sure I'm leaving something out but you get the general idea.  Many common parts to the same year k bike but a lot of unique parts too.