Starting a motor after a long stand

[CafeGuy]

Hi Guys new to the forum so greetings all around!

I have just bought a 79 CB750k and its been standing for at least 2 years but probably more like 5 years after having no problems previous owner just lost interest! I want to start her up as soon as possible but have heard that head should come off and valves checked before I try from some and others say its not necessary.

Your'e thoughts on this and anything else that should be done to the motor before trying to start her after such a long time?

Any help is appreciated.

[sgtslag]

Replace the oil, and filter.  Drain the gas tank, fill with fresh gas, mixed with SeaFoam, as per the instructions.  Top off the battery's charge, then...  Start her up.  Likely, it won't start, due to plugged jets within the carbs, but it won't damage it to try.  The oil is viscous enough to cling to the metal parts, so there will be very little friction wear when you start it.  The oil pump will begin pumping the fresh oil, as soon as the engine turns.

Download the Factory Service Manual, from the home page of this site.  If you are interested, there are numerous discussions on how to bring these bikes back to life (what to do when a bike has been sitting for years...), as well as how to clean the carbs, and other maintenance issues.  First order of business, though, is the carbs, and replacing the oil and filter.  Cheers!

[TOOLS1]

"Remove the head"? Who ever told, you that needs their head examined! Just do what Sarg recommended, and it should run. You might want to give it a shot of starting fluid if it does not fire. If it fires on the starting fluid, then, you will know that the ignition system is working.
TOOLS

[robs750]

I'll add more!

If it's been sitting for 2-5 years like you say,I don't think the battery is going to be good.If it's a wet cell battery,you could check the acid level and top off with distilled water and try to charge it.Replace the battery if needed.

Once you have battery power,I would change the oil/filter like said.Use an inexpensive oil.
Check the air filter.
Remove the tank,drain the tank,check for rust,flush/clean out as needed.
Fill with some fresh fuel and check fuel flow from the on and reserve posistions.Check fuel line for cracks/hard rubber.
Clean all around the plugs,then remove them.You don't want junk falling into the cylinders!
With the plugs removed,I would squirt a little oil in the cylinders then crank the engine over to prime the oil pump/lines.Install the plugs in the caps and and check for spark on each plug.
When cranking the engine,you can kind of check for compression by placing a finger over the holes.
If the old plugs were sparking,install them.Have a fresh set on hand.
Put the tank back on with fresh fuel,connect fuel line and turn on the fuel.Check the carb overflow drain tubes.They should not be leaking.
Now with the fuel on,flush each carb bowl by unscrewing the drain valves.There should be a steady flow out of the overflow tubes and then the flow should stop with the valves closed.

Now it's time to start it!

If it starts and runs,that would be great.Road test it.
From there,I would change the oil again with the engine hot.
Remove the tank,valve cover and check the valve clearances with the engine cold.Adjust as needed.
Replace the cover  gasket and the bolt seals if needed.Check the compression.
Install the new plugs.
Adjust the carbs.

If it does not start or runs like crap,most likely the carbs will need to be removed and rebuilt.

Hope this helps.

[rrgunslinger]

I remove my head all the time, but my wife makes me put it back on.  Says I would scare the dogs!

 

[Jeremy]

Carb clean Is always a great idea.
I like to put a little oil down the spark plug holes then do the other work.
Not sure if oiling down the cylinders helps but it makes me feel good.

[shultz_1978]

CafeGuy you are on the forum. If you have any problems getting her back up and running with some info of what the bike is doing at the time you will get a lot of help here to do it your self. Some time we like to see pictures of the bike. 

Good luck with you project at hand. Some times it just take a little patience.