Topic: My 78 CB550 says I need to change shops (or do work myself)

[Sporkfly]

You can replace a cam chain if it needs it, I promise you have the capability. This bike and my Audi are the reason I'm a certified mechanic now. Motorcycles are satisfying to work on and Audis are necessary to work on (unless you have very deep pockets, which I definitely don't). If you can read the manual, you can rebuild these engines. If you've ever pulled apart a lawn mower then you're on the right track to fix anything engine related on these bikes.

Don't take it to the shop anymore, I'm willing to bet they just want your $$$ speaking from personal experience and knowing many mechanics. Reputable shops are not commonplace, and the information is all here to get you where you need to be. Don't get rid of the bike! (and if you do give it to me )

Beyond that: Did they replace the o-rings on the inboard carbs?

Also, the FAQ section has great information on cam chain adjustment.

[locostbamboo]

So the latest is I can't get the bike started now.  Yesterday, I was able to get it started by turning the idle screw way up and they backing it down (quickly) once it started.  Now it won't start at all. I am going to call the shop, though I really don't want to take it back there.

[Hannibal Smith]

Quit taking it to that shop!

You jack the idle way high to start her, then chop it back down right away- That's not how these cats work. These fantastic machines are not "Plug-n-Play", these are from an era of self-reliance.

What you need to find is a local guy/gal that knows how to mess with these bikes, they are SUPER simple once you understand how they work.

You have a 1970's bike, this stuff is part of the experience.

 

[Gordon]

I am going to call the shop, though I really don't want to take it back there.

Don't do it!!!!

You're only asking for more trouble and giving away your money on top of it.

[TwoTired]

Now it won't start at all. I am going to call the shop, though I really don't want to take it back there.

Yikes!  I'm told it feels really good the moment one stops bashing ones head against the wall.

Seriously, if you are not going to learn to work on the bike yourself, or find someone who is competent to work on it, you are far better off selling the bike and getting a newer one with a service warranty.

These bikes are pretty reliable when kept up with routine maintenance.  But, if the maintenance is bodged and fumbled, it's only use is that of an ornament.

[locostbamboo]

So I am trying to figure out why it won't start.  I am guessing it could be flooded. 

[TwoTired]

We need more specific description about sysmptoms.

"Won't start" is too general.
Do the lights come on?  (dead battery?)
Does the starter motor not spin the the motor?  (battery depleted?)
Can't start with kick starter?  Lights dim.  sure would be good to know the battery voltage.
I just got a Harbor Freight coupon for a Digital multimeter for $1.99.

Do you have a tool kit?

Can you pull the spark plugs?

Do you have gas in the tank?  Will the bike start if the gas valve is in the reserve position?

Does the engine spin but not show any igns of firing?

Do you have the owner's manual?

In general, the more information you give us about the problem and the bike, the better equipped we are to help with diagnosis and corrective action.

Cheers,

[locostbamboo]

Gas, yes.  Lights on.  Starter spins engine.  No difference in reserve versus on position.  Can pull plugs and will do so.  Will get an owners manual.  Did download the one from this site.  Won't kick start either.  Have multimeter and will check battery.  Acts like it is not getting gas, but tank is nearly full, and gas is on.  Wife is after me to take back to shop as she has doubts about me working on it.  I have doubts as well, but want to learn.
Thanks!

[TwoTired]

but want to learn.

That is you most important asset.

Can you describe your starting procedure?

Here's mine.
Turn on gas valve ( I always turn to off when I stop the bike)
Apply full choke.
Turn lights off (if bike has a separate lighting switch)
Turn on key switch  (make certain the stop-run-stop switch is in run position)
 Hold throttle to about 1/4 open position.
Kick or electric starter spin the motor.
(Variation between bikes here.)
Vary throttle position idle to 1/2 until engine catches.  Remove some choke use partial until engine gets to operating temp.

After you learn what your bike likes, you may not have to vary the throttle during start, and will know where it likes to have it for starting. (Most of mine like the 1/4 position when cold, one likes to alternate between full and idle position.)

Normally, it will only start in idle throttle position when the engine is at full operating temperature.

Cheers,

[locostbamboo]

OK, so I thought it was not getting gas.  I was looking at the fuel filter and it looked like they changed fuel lines.  I pushed on the new, spongy lines and it fell of the carb inlet.  I replaced the lines with proper lines I had and it fired right up.  the lines they put on were too big ID, and were letting air in, I suspect.  Thanks to all of you for listening to me.

Rob in Oregon

[andy750]

Excellent news Rob! Welcome to the world of SOHC motorcycles and DIY mechanics 

[campbmic]

Its weird the more things like that happen the more you fall in love with the bike and realize how much smarter it is then you. You also get a bigger grin when you hop on it start it right up and ride down the road.

By the way my buddy has a 79 GS425 that needs a carb cleaning. The shop wants $325 to do it and it only has two carburetors!

[Stev-o]

Glad to hear it! You have got to feel good about getting it running [and you can tell the wifey you did it!]

[locostbamboo]

I did it over lunch.  She was home sick and I came in and told her I thought I figured it out and was going to start cutting and installing fuel lines. She asked if I needed to do this now and in my work clothes and my answer was yes.

I did have some issues getting it started back up when I left work this evening.  When I explained that to her and she started to give me the look, I told her that I got it there and i got it back home and that was the important part.   

[Stev-o]

I did have some issues getting it started back up when I left work this evening. 

As TT explained above, you need to figure out how your bike likes to get started, then do it that way.

Good Luck.

[Old75_ratafe]

I did it over lunch.  She was home sick and I came in and told her I thought I figured it out and was going to start cutting and installing fuel lines. She asked if I needed to do this now and in my work clothes and my answer was yes.

I did have some issues getting it started back up when I left work this evening.  When I explained that to her and she started to give me the look, I told her that I got it there and i got it back home and that was the important part.   

You also were fiddling with your idle and stuff it might just be off now.  I would take those fuel lines back to the mechanic throw them on the table and ask for your money back.

[Frostyboy]

Welcome to the world of SOHC motorcycles and DIY mechanics 

Before you bag me, yes I did change this pic from Ducati to Honda.

[dave500]

a bit of a look,a bit of a feel and youve fixed it,,put a 175 dollars into your own bank account!!you can download a manual on this site if you havent already,,itll have things like plug gaps and points settings,clutch adjustments,now its going,and going to get ridden some care and attention as you go is going to needed to be done,good on ya.have you got many tools?,if you need to buy some ,buy in sets,even if some of the sizes wont be used,metric for the honda,,and any jap cars.

[bistromath]

I'm sure you've already taken it to heart, but remember that lesson: the mechanics screwed it up, and YOU fixed it!

[rm56]

My 750 developed a fuel leak when the small orings on the fuel "T"s between the inboard carbs wore out. I went to a shop to pick up the bike. I turned on the gas, started it and noticed alot of gas pissing all over! I killed the engine and quickly saw that the two small tees were leaking. Simple fix, I found some small Orings at an auto parts store that fit the Tees, no more leaks. Of course if you took your carbs apart you used new gaskets...right? Ya can't reuse the gaskets unless you want a flaming ride. I agree with the cam chain being at bit loud. Some guy on a Hog one day said yer chain sounds a bit loose? Nope it just is the way it is. Besides on a 74 CB750 its a spring loaded adjuster. You just have to loosen it a bit then snug one 10mm and it adjusted. Not sure where you live? I'm in Northern Calif. I found an old Kawasaki wrench up in the foot hills who is a great mechanic. He restores older classics both street and MX. Nice guy really knows his stuff. The young kids don't know jack about our older Hondas. Hope you got it done. 

[Grnrngr]

Rob in Oregon

Where in Oregon?  I think we have a good mechanic here somewhere....heck, maybe two!! 

OH YEAH....we'd like to know about shops that DON'T know what they're doing....

[the technological J]

i sold my buddy my 78 550 and when he has a bug he cant find he starts into  like 5 different things and causes 3 more problems and then i have to bail him out..... but when you come across some thing that needs fixxed or put back into spec start focus on it and do ur investigation systematically othere wise you'll tear apart your bike and then realize it wasnt starting because you had the kill switch in the of position or 2 cylinders wernt firing because the bike was leaned to far on the kick stand and couldnt gravity feed gas to the starving carbs.... but one thing at a tiem so if the bike doesnt start you'll know what it was that you did to keep it from working

[birdy]

Just reading through this; last post said carbs can be starved if left and started on side stand- another nugget of info that is new to me. Brilliant