78 cb750f supersport clutch issues, need some ideas

[OApb]

Hey guys, I just brought my new purchase and have a few questions on some things it needs done. first things first it is a 1978 cb750f super sport. First issue, the clutch lever is VERY hard to pull. I was told the clutch plates were replaced and may just need a warm drive adjustment? That is the flat head screw under the housing on the left side right? I was told to take the cover off, loosen the screw then to tighten until some resistence is felt and then to back it out 1/4 turn. Is that procedure right?

next issue, the bike seems to have no spark. I believe that it is the points as I cant see both coils going bad. The bike turns over but does not fire up. Anyone have any other ideas I can try before I spend the money on the points plate?

Other than those 2 issues the bike is in great condition. Only has 21k on it along with some sort of aftermarket exhaust and clubman bars which I believe I am swapping for a set of clip-ons. Thanks in advance

Nick

 

[Koestum]

All four plugs have no spark???

There are a lot of possibilities here.
Ignitions switch terminals corroded?
Blown fuse?
Weak battery?
Bad ground?
Bad points?

Pull each plug and hold them to the cylinder head to see if any plugs have spark or none of them. If at least one of four does then it will help narrow down the list.

 

[OApb]

I would assume if some of the plugs had spark, the motor would atleast try to start so Im guessing that all 4 arent getting spark. The motor turns over it just wont fire up at all. I will try some of those things and see what I come up with

 

[Koestum]

The engine would try to start if the air/fuel ratio was close and if compression was good and if the spark is strong enough and if timing is right.

There are too many variables going on to assume it's a spark problem when the engine won't start.

Here are some basic common sense steps I try to run through one by one when I have trouble but you should really do an oil change before these just to be safe.
1. Verify that the key is turned on.
2. Verify that the handlebar switch is set to "Run".
3. Verify that the battery has a full charge.
4. Verify that it has gas in the tank.
Try to start it.
5. If it won't run then verify that the fuel valve is allowing fuel out of the tank and clean if necessary.
Try to start it.
6. If it still won't run then verify that it has spark by pulling out each plug one at a time and hold to the cylinder head while turning over.
7. If no spark on any cylinders then start checking fuses, ignition switch terminals for corrosion, something unplugged, etc...
8. If some plugs have spark then at least you can rule out some things but it should try to run.
9. Spray a bit of starting fluid in the carbs, and close the choke.
Try to start it.
10. If nothing happens check the timing and the points.
Try to start it.
11. If nothing still happens then let us know.
12. If it runs for a moment on starting fluid then move on the fuel delivery issues.

 

[OApb]

Hey, I went through your list and still nothing. The carbs get fuel, all the fuses looked ok but I replaced them anyways (had a bunch of the same type from my 72 chevelle). I pulled all the spark plugs, one at a time, and none of them spark. My best guess would be the points or coils or both, I could be wrong though as Im know more about cars than bikes.

 

[Koestum]

My best guess would be the points or coils or both

Take the point cover plate off.
Clean the contacts and and make sure the gap is correct.

If the contacts are touching you can use a small screwdriver tip on the spring side to open them and it should spark OR try to start the bike while watching the point's contacts to see if a spark is jumping bwtween the contacts.

The spark can be hard to see in daylight so after dark is better.

If it sparks then you know its at least getting that far.

The spark plug boots just unscrew from the plug wire. If you remove the plug boots you can hold the wire close to the head while trying to start and see if spark jumps that way.

Sometimes you need to cut a bit of the end off the old plug wire, maybe up to 1/4", and screw the plub boot back on. I think this is an unlikely situation for you since you say all four plugs are not getting spark.

 

[OApb]

Take the point cover plate off.
Clean the contacts and and make sure the gap is correct.

If the contacts are touching you can use a small screwdriver tip on the spring side to open them and it should spark OR try to start the bike while watching the point's contacts to see if a spark is jumping bwtween the contacts.

The spark can be hard to see in daylight so after dark is better.

If it sparks then you know its at least getting that far.

The spark plug boots just unscrew from the plug wire. If you remove the plug boots you can hold the wire close to the head while trying to start and see if spark jumps that way.

Sometimes you need to cut a bit of the end off the old plug wire, maybe up to 1/4", and screw the plub boot back on. I think this is an unlikely situation for you since you say all four plugs are not getting spark.

I will try that tonight and let you know. Thanks alot

 

[OApb]

went through everything and the no spark issue ended up being a disconnected wire behind the headlight. what a ratsnest back there. Good thing is the bike now has a new points plate ;D now I just have to time it again. The clutch issue ended up being a very clogged and dirty clutch cable which i replaced as well. Bad thing is I broke the clutch perch and a new OEM one is $65 :-\ I think Im going to buy a universal one off ebay.