Long time lurker, first time poster!

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Ricardoc4

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Hello!

I want to introduce myself and tell a little about myself!
First of, I'm from Belgium and I'm not a native english speaker so prepare for some grammar mistakes!

Ever since I was a little child I dreamed of riding a bike into the sunset.
While my friends were dreaming about the latest sportbikes, my dream was a cb750!
I'm 22 of age and never had the time to immerse myself into the world of motorcycles.
When I was 18, I was working seven days a week. And the time I had left, I was helping my parents.
My father had a full-time day job and my mother had several operation on her spine.
About a year ago my father had a cerebral infarction and he is still recovering.
Now I'm 22, and I'm selling bathrooms for one of the marketleaders in the sector.
I have more time and I'm lucky to have a good paying job to help my parents.
Never ever did they asked me for money or help!
But I am lucky enough to have such great parents who did everything they could to raise me to the person I am today.
So every month I anonymously send my parents enough money to help them get by comfortably.

And yesterday my dream became reality!
I am now a proud owner of a '79 cb750kz.
The overal state of the bike is poor and non running but it was a bargain.
The plan I have with the bike is to build a cafe racer out of it.
Since I am not mechanicly skilled I was hoping to complete my dream with the help of this forum.
As the title stated, I'm a long time lurker but first time poster.
I have seen that this forum is filled with skilled, friendly people with the same passion.

I Hope to be accepted by the cb750 forum community.
Greetings,
Ricardo
image.jpg​

Apparently something went wrong. This was supposed to be in the 'intro' section..
 
Well Ricardo, I don't think you need to worry about your English... except maybe that your grammar is better than most of us in America.

You sure found a nice looking bike. Do you know anything about the history, such as how long has it been since it was last ridden, and if it was put into storage, was it running at that time?

I'm hoping you'll find an easy fix to get it running, and with a few more details, maybe someone here can help you out.

It's my bet that you'll be mechanically skilled on that bike before you know it.
 
Always nice to get a compliment on my English!

The person who sold it to me had it for 16 years.
It was stored 2 years ago and according to the seller, it was running at that time.
The tires and battery are shot, thats for sure. Also, the front brake doesn't do anything.
The brake lever isn't giving any pressure and the brake won't engage.
I want to make a step by step list that will get it running.
It's not my primary target to get it perfect immediately, I just want to hear it run.
So I'm thinking clearing out the old gas? (What is the best method?)
And ofcourse replacing the battery. I'm pretty sure it was running very rich because it stinks of gas and the carbs are leaking gas out of the overflow hoses (is that even a word?)

Greetings,
Ricardo
 
Wow Ricardo... I might be a little optimistic, but I'm betting that you got yourself a great deal, and it will hopefully be an easy one to get running as well.

If your priority is to hear it run, like mine would be, I'd do a few things up front just to make that happen, although other things will of course be necessary to make it road ready.

1. You're right, get rid of that old gas. The method depends on the condition of the tank, in my opinion. If it's rusted inside it needs to come off for cleaning... if it's just old gas, you might get away with disconnecting the hose from the tank to the carburetors and just drain it by turning on the petcock. You would need to put it in the "Reserve" posit to get the most gas out. You should then add a little fresh gas, maybe a couple of liters or so, and drain that too to get more of the bad gas out... there would likely be some old gas still in the tank bottom from jet draining it, but you will be able to see that and have a better idea on how much new gas to use to help clear out the old.

Be sure and look closely for rust inside the tank. If it's rusted, you need to get it clean because the rust will end up in your carbs and you don't want that after you get the carbs cleaned... and it could be rust or other debris that's keeping the carburetor float valves from sealing, and the gas coming out the overflow hoses.

If the tank is rusted inside you should take it off. If the seat flips open, just unlatch it and get it out of the way so the tank will come off. Turn off the petcock, disconnect the hoses at the petcock, and remove any bolt that may be in the rear of the tank securing it to the frame. Look at the bottom of the tank and see if there's a small hose that goes from one side of the tank to the other and if it goes under the frame tube... if so, you'll need to disconnect one side to get the tank off, so you'll need to get most of the gas out so you don't get gas all over the bike and floor when you disconnect the hose. If there's no hose, or if it's above the frame, the tank should be ready to come off. Raise the tank and pull it rearward to get it off the rubbers on each side of the frame at the front. Be careful to not raise it too hight at the front and hit the handlebars or something else that might dent or scratch the tank.

If it's only been a couple of years since the bike was operational, I'm assuming the gas is just old and needs replaced, so won't go into cleaning the inside. If it's not clean after flushing with new gas, help is available for cleaning options if you need them.

2. Once you get the old gas out reconnect the hoses to the carbs. Loosen the screws at the bottom of the carb bowls and open the petcock to drain the old gas out of the bowls and replace it with the new from the tank. Close the petcock and retighten the screws at the bottom of the carb bowls. Reopen the petcock to see if the carbs still leak at the overflow tubes. If so, try tapping on the float bowls that leak with the handle of a screwdriver. Don't beat on it, just tap it hard enough to get some vibration that might free up the float valve an let it seat properly.

If the gas keeps flowing, you'll need to decide how badly you want to hear it run and whether or not you want to remove the carbs of cleaning before trying to start it. Personally, I'd probably just be sure I had a pan under the bike to catch any gas overflow, but that doesn't make that method right.. I just want to hear the bike run! Besides, once the bike starts, there won't be as much gas overflowing, if any... so I'd just turn off the petcock until time to try starting the engine which will stop the overflow.

3. Now you need to check the oil. For one, you need to be sure it's full. Secondly, you need to be sure that gas that's been overflowing through the hoses didn't also go through the carbs and into the engine crankcase. The best thing to do is change the oil and filter... you're going to do that at some point anyway, so might as well be now. When you change the oil be sure to check to see if there might be gas in it from the carb floats that didn't seal. My point is simply that when gas doesn't seal at the float valves, it could end up in the crankcase... so close your petcock when the bike isn't running to ensure that there's no overflowing going on, even after you get the bike road ready.

4. Look the bike over well in search of amy frayed or disconnected wired. Look for signs of mice or insects that might have made homes in your bike. Look particularly well in the air box, and check the air filter while you're in there. Clean whatever might need cleaned to prevent sucking dirt into the cylinders. If you have a friend who might be more familiar with motorcycles, have him check things out too, and get any advice he might have.

5. Now you should have gas, oil, and clean air flow to the carbs... you need a battery. Put in a freshly charged battery and you're getting really close to finding out if it'll run.

6. I'd probably be pretty anxious at this time and would be turning on the ignition and pushing the starter button to see what happens. It would hopefully be running. If it doesn't start up within a few seconds, I'd replace the spark plugs. At that point I'd check the old plugs to see if they were wet from gas or not, just to be sure gas was getting through the carbs.

Notice: I've skipped a lot of things that are hopefully obvious. Like making sure the bike is in neutral, there's not gas all over the bike or floor, the kill switch is in the "Run" position, and other things that would probably come to mind based on what I found from checking out the bike. I'd have the bike outside with nothing around it. Not to scare you, but consider what might could go wrong... like what if the bike jumped into gear? (If it's on the main stand and wheel off the ground, no problem... just turn it off or flip the key or kill switch.) What if the bike starts and the engine goes into very high RPM? (Turn off the key or kill switch.) My point here is that there are many things to consider, so you need to plan ahead and be prepared, and careful.

Anyway, I probably left something out, but this should be a good start. i could have suggested that you remove and clean the carbs... put an inline filter in the fuel line to the carbs... fix the brakes... etc. All I've tried to do is give you an idea of things to check before trying to start the bike simply to get past the question of whether or not the bike will run.
 
Wow Tommycarl!

You just saved me a ton of searching!
I have no doubt that if I follow your guidelines, I will hear it run in no time and saving me a lot of money while doing it!
It's hard to look at the bike and restraining myself not to skip any steps that will eventually bite me in the ass.
The first day I will have time to begin is Tuesday (because of my girlfriend). The problem is that it is a national Holliday here in Belgium.
So it won't be possible to get supplies like oil or something like that.
I'm guessing that I won't be able to do much other than stripping the bike and do an overall check and cleaning this beast.

And last but not least, I always told myself that the first person that helped me with the bike is the one who may name my bike.
So Tommycarl, what will it be?

Greetings,
Ricardo
 
Heck Ricardo, if you want to know the truth, I'd probably skip a bunch of those steps. lol I'd probably be checking the oil, changing the gas, hooking up a battery, and pressing the starter button. If it didn't start right up I'd take out the spark plugs, pour a little gas in there and try again! But then, you'd probably be safer doing it the right way, not MY way. lol

On one hand, you say you aren't mechanically skilled, but on the other hand, I have a suspicion that you know more than you're letting on. I think you're going to do just fine.

Name your bike, huh? Now you're trying to get me into trouble. The obvious name is that of your girlfriend if you want to make some huge points with her. I already have trouble remembering I'm working with Ricardo here, because I always think it's Ricky. You know, Ricky Ricardo from the old I Love Lucy TV show? lol

Although I feel a bit honored that you might allow me to suggest a name for your bike, you should probably do that yourself, and maybe wait until you get it set up as the cafe you have in mind and see how well it runs. An appropriate name might then come to mind, like maybe Pokey: Speedy; Dog; or Bullet... and what the heck, do you want an English name for your cafe?!?! lol

Do you have a manual for your bike? If not, you might try this link: http://www.cb750c.com/modules.php?name=Forums&file=viewtopic&t=5 I'm not sure it's exactly right for your bike, but I'd bet it either is, or is really close to the same. I actually heard of the Honda KZ only a couple of weeks ago via an online forum, except for the KZ1100 like I have... and it's a Kawasaki!
 
I think that your suspicion is only half true.
I'm a 'youtube skilled mechanic' if you know what I mean :D
I've been constantly reading and watching YouTube on and of for the past 2 years.
And although the name of my girlfriend maybe a good suggestion, she isn't happy with me buying the bike in the first place.
But on the other hand you've given me a good idea with the Ricky Ricardo thing.
I think I'm going to call her Lucy until further notice!

And I can't open the manual since I'm not a member of that forum.
Maybe it will help you that it a 'RC 01'?

Greets,
Ricardo
 
Well if you don't want to join that forum to get the manual, I think you can get one here: http://www.mediafire.com/?klfelhtf6ke5a I opened Chapter 1 from the list of downloads and it looks like it's the one for your bike. However, there's also a lot of good information and help at the other forum as well. However, when I first started going there the people who run that place aren't nearly as friendly as in most forums I visit... I think they may have improved their attitude some though.

I like Lucy... she's pretty unpredictable though, so be careful!
 
Well, Lucy has already baffled me!

Today was the first day I could work on it.
I've gotten al of the old gas out of the tank and carbs.
Changed the fuel filter, oil filter, oil and spark plugs.
And wowwwwww, the oil was filled with gas...

But she just won't start..
The guy at the local store said that the battery I have is still good.
But she doesn't even turn over.. I only hear a clicking noise and a soft 'starting sound'

Kinda need help right now..

Greetings,
Ricardo
 
Okay Ricardo... firs tI need to be sure you understand that I really don't know your specific bike... so you need to be sure and check for reasonableness before you run with some of my suggestions. I think I'll be fine for the most part, but it certainly wouldn't hurt for others who might be more familiar to jump in, and for you to look at he manual when possible.

So for the clicking and soft "starting noise" you hear... can you pinpoint the area of the noises? If it's the starter itself, you might try disconnecting the cables at he starter and at the starter solenoid to be sure they're clean and you have a good connection. Same for the battery connections.

If it's coming from the LH side of the engine cases toward the front, like just inward of where it says "Honda", it could be the starter clutch... 3 round pins maybe 12mm long and 10mm diameter (some just for reference, I've never measured them but should be close) and springs that make them work when the starter is turning. You can see the starter cover just below the carbs. the drive gear will be on the left hand side, and turns the starter clutch. To fix the starter clutch might be easy, but you'll need to remove the LH cover to get to it, so we'll focus elsewhere right now.

Take a screwdriver or wooden dowel... something solid for noise to travel along... and put one end near the starter LH end, the other end on your ear. Push the starter button and see if you can determine where the noise is coming from. If there's more noise 3-4" to the front than there is at the end of the starter, I'd suspect the starter clutch.

The starter solenoid can also come into play here. If it was me, I suppose the 1st thing I would do is touch your screwdriver across the two larger terminals of the starter solenoid... all that does is complete the connection just like happens when you push the starter button, but it also sparks and might burn your screwdriver or the terminal where it touches. You get to decide whether or not you want to do that... If you jump the solenoid and the starter works fine, it''s probably either the solenoid or bad connections there.

Let me know what you find...

Anyone else watching is certainly welcome to add suggestions.
 
I tried to jump start it with my car.
It turns over so the guy at my local shop was wrong about my battery.

I'm getting a good spark on al four of my spark plugs.
Al the plugs are moist except the first one.

When I jump start it, it turns over but won't ignite.
I'm getting exhaust fumes so something is definitely happening.

Others can jump in to help of course :)

Greetings,
Ricardo
 
No problem.

First of all, don't try running the starter for too long... we don't want to burn up the starter, I'd say that 10 seconds maximum should be plenty before letting it rest.... that can be a very long time, so be careful with that.

I'd suggest that if the plugs are very wet, you may need to blow them off or even be prepared to replace them. You're probably fine, but be sure the spark plug wires were connected correctly. Not much chance they're wrong if stock, but worth taking a look.

I'd clean the plugs and try again if you don't have an extra set... or put the old ones back in if you have spark with them too.
 
I will try that.
And now prepare for a dumb question, does it matter which spark plug wire connect to the spark plugs? :rolleyes:
If so, how do I check the right order.
And all the spark plugs are brand new.
 
Spark plugs wires must be connected to the right place... or you might get popping. There are 2 coils. One fires spark plugs 1 and 4, the other fires plugs 2 and 3. that being the case, you shouldn't have a huge problem getting them correct if the wires are stock because the shorter wires won't reach the outside plugs (I hope). If someone has changed the wires over the years, that might not hold true. You might also find numbers on the plug wires. Cylinders/plugs are numbered from left-to-right as viewed while riding the bike... 1,2, 3,4 from left-to-right.

If the plugs are too wet, the plugs could be flooded with gas. Either dry them off like with an air compressor, or replace them. They can flood/foul quickly. If only 1 plug fouls, it might still start and run until the plugs kinda cleans itself up. But you have 1 dry plug, so if another fouls, you're on 2 cylinders trying to run... could still run, but you get the idea as to how chances go down as more plugs foul.

Don't get too anxious. If you think it could be flooded, try to be patient. take the plugs out and let the bike sit awhile... an hour or so maybe.

I hope you don't have to go this far, but here's a link to a very nice carburetor rebuilding manual... I don't suggest that you give up just yet, but you can read this while you wait for the cylinders to dry out:

http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revG.pdf
 
The spark plug wires are all equally long and they can reach all of the spark plugs.
Is it even possible to get the bike started with bad carbs?
 

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