78 cb400 hawk 1, new to motorcycles.

[ChadLatta]

Hello. I have been browsing this site for a bit and decided it was time to put forth some questions.

First off, I will say that I have limited mechanical experience, just the basics. I have done some work and own most of the tools I think I am going to need. I am a quick learner, so I am not too nervous or overwhelmed and there are plenty of resources that I can turn too.

I recently purchased a 78 cb400 hawk 1. It is my first official bike. I am getting my endorsement in August and other than riding dirt bikes growing up, I have limited riding experience. So, I have plenty of time to work in this bike and I plan to take it slow all around.

Now, onto the bike. It was cheap, has a clean title and runs. I did some research about the bike before I purchased it and decided that it would be a good start. I bought it sort of as a half first bike, half fixer upper project. I have seen some posts about this bike being worthless, slow, no better than a pile of junk...etc. I'm fine with it, I'm not looking for a high performance machine right off the bat anyway.

I am not sure exactly where I am going with this bike. I want to do a cafe style bike and have thought a lot about seats, bars, etc. But, my first and foremost priority is getting it up and running, safe and solid...then I will kind of go from there. I tend to get ahead of myself and go full speed ahead, so who knows....but I do want to get it running and solid first.

The bike currently runs. Not poorly, not well either. Some issues I have noticed.

1. It is running rich (I assume). I put my hand behind the pipes and notice it is spitting fuel. Not much, but enough to notice on my hand. It has never backfired and sounds decent, so I don't think it is too bad. I plan to pull the bowls off the carb and just kind of go from there, but it could also be a valve issue.

2. Compression is low. I did one test and found it was 60 in the left side 90 in the right. I then realized i didn't open the choke and turn the throttle, so I re tested it properly and get 120 for left and 150 for right, engine cold. I used a cheap harbor freight gauge, so I will probably do it again to confirm what I found today.

3. The kick starter slips every now and then, like it is not grabbing. It works 95% of the time and starts right up, so I don't know if that is normal or what.

4. This is the big one I am mulling over right now. There is a loud ticking sound from the top end. I used the screw driver to the ear trick and determined it was mostly loudest at the top left. I adjusted the cam chain and nothing changed.

My next move is to check the valves. I have a shop manual that I downloaded that seems to spell everything out well, but I want to get the cover off and go from there.

Any advice, tips, general knowledge you can give me? Am I on the right track?

Also, gaskets.....can I simply make my own gasket and what thickness would work best?

I have posted this in another forum, so if your reading it twice, sorry!

Also, should I start a "build" thread somewhere to post my on going questions, or does this work?

Thanks,

Chad

I can't seem to attached a photo with the iPad, so I will get it up soon.

 

[ChadLatta]

One quick thought, question regarding the ticking. The previous owner did not own the bike long. He changed the oil and rode it for a bit.

I put new plugs in it and checked the oil, but have not changed it yet. It looks new and clean however.

But i was wondering, if he had used a standard oil, say 10w30 for your car, would that have any thing to do with the noise?

I plan to use Rotella 15w40 HD, based on others recommendations.

Thanks
Chad

 

[paddlesat16]

Hi

Pull out the plugs to check for running rich, just cus it's spitting out of the exhausts doesn't mean it's rich. The plug colour will tell you most things about how an engine is running. Biscuit brown is the colour you want, white is running lean and black is oily/rich.

If the PO used car oil, it depends on what type of car oil he used. Fully synth is no good for this bike, it needs an older type of oil. Mineral based is good but you can use 10w/40 semi synth bike oil without any issues.

The ticking sounds at the top is the valves, they are easy enough to do on the cb400n/hawk

Before tearing into this bike make sure the carbs are clean, and balanced as this makes a big difference to the power the bike can develop. Keep the air box and don't be tempted to ditch it in favour of pods or stacks; the carbs are cv carbs and won't run right with them. Go factory settings on the carbs and the bike will run right.

Regards

 

[axeugene27]

First off welcome man this site rocks. Hey my first bike was a honda hawk 400 but i think it was an 80 i remember my first street ride on it i was scared to death. Long time ago. Try loosening your clutch adjustment to see if that affects the kicker sometimes it is engaged and the kicker will just slide. I learned this very recently. Pull in your clutch and kick it you'll see what i mean. If this is your first bike and you plan to learn to ride on it let me tell you what you need to check and upgrade before anything. 1. tires they had better be good and safe
2. drive chain you don't need a rear wheel lock up at high speed.
3. Brakes should have plenty of wear left in em.

Have fun man change this to a build thread and give us some pics for petes sake it's what we live on .....

 

[HerrDeacon]

I have seen some posts about this bike being worthless, slow, no better than a pile of junk...etc. I'm fine with it, I'm not looking for a high performance machine right off the bat anyway.

Just ignore posts like that, they are obviously from people that don't have a clue. Nothing wrong with these bikes at all. I had a '80 and found it really good. Great bike to learn the mechanics on too since they are real easy to work on and everything is easy to get at.

I think you're on the right track. Before attempting another compression test, adjust your valves first. Then once they are adjusted, warm up the bike and take the compression reading again. The 120 is pretty low, but hopefully its just the valves. After this, adjust your cam chain and balancer chain.

You should always change the oil anyway when you buy a used bike, never know what the PO used or how long its been in there. Rotella is a good choice, I use it in all my bikes.

Let us know if you have any questions when you do your valves and how the compression numbers look. Have fun!