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Bike won't start, can't get clutch adjusted

  • Thread starter Thread starter cj7jeep81
  • Start date Start date
C

cj7jeep81

Guest
Picked up an 81 GS750L a couple months ago, with the plan to go through it and get it ready for spring. When I bought it, it would start right up (with a lot of choke), and run fine.

I first pulled the valve cover, and adjusted the valves (they were way tight).

I decided to replace the handle bars, and put on a set of drag bars. I bought a new throttle cable and clutch cable. Got them put on, and put the bike back together.

Now, it will not start. It will crank, but won't fire. I found that the fuel line was pinched, so I replaced that today (pain in the rear to do), and it still won't start. I put it on prime for a while (at least a minute or two), and crank and it will not catch. I can't smell any fuel when I remove the air filter, and when I pulled a couple plugs, they were sooty, but didn't smell like gas. If I disconnect the fuel lines and put it on prime, fuel comes out. I've tried with the choke fully out, fully closed, in between, etc. Tried starting with prime, reserve, and normal (has a little over half a tank of fuel).

Also noticed that the clutch isn't working. If I put it in gear and pull in the clutch, I can't turn the wheel by hand. I turned the adjuster at the handle all the way in, and have been backing out the adjuster on the case, but no difference. The lever pulls smooth, and I can see the cable pulling the level on the case as soon as I start to pull, so not sure what's wrong. Do I just need to keep backing out the adjuster on the case?

Thanks for any help.
 
Welcome. Have you already verified you have a good battery? What kind of voltage are you getting with the key off, on, while trying to start? Are all of the fuses verified good using a test light?
 
Well, try to verify spark, but it sounds to me like your pilot, idle, and/or choke circuits are gummed up. With modern ethanol gas it doesn't take long. If you think your bike might sit for more than a couple of weeks, it's a good idea to add some stabilizer like SeaFoam into the tank. Unfortunately a carb cleaning is probably in order. Make sure your tank is clean!

Though, since you replaced your cables: make sure there's a little slack in your throttle cable (IIRC the spec is 1mm slack). If the cable is tight and holding the throttle open you won't get enough vacuum to pull the necessary fuel in.

Someone else will have to clue you in on the clutch, I believe the 550s like mine have a way different mechanism...
 
Previous owner replaced the battery in the last year. I haven't checked voltages, but when its fully charged, it cranks fast and seems to be ok. Haven't checked the fuses either, but will check them.

Guy I bought it from had the carbs cleaned (he had bought the bike after sitting a long time, and he got it fixed up and running). I haven't pulled them (other than to replace the fuel line), but it was starting/running fine before I started working on it, so doubt they've gummed up in the last month or so. I'll check the throttle, and see if its adjusted too tight.
 
cj7jeep81 said:
Guy I bought it from had the carbs cleaned (he had bought the bike after sitting a long time, and he got it fixed up and running). I haven't pulled them (other than to replace the fuel line), but it was starting/running fine before I started working on it, so doubt they've gummed up in the last month or so. I'll check the throttle, and see if its adjusted too tight.
Click to expand...

If my 2002 Bandit 1200 sits for ore than a month it runs poorly with a miss fire for the first few hours, bogging down and being a real pain in the bum.

My 1981 GS1000E is even more of a pig if it hasn't run for a few weeks.

You've checked the fuel line and fuel tap (pet cock) and its drawing fuel so I would start with gummed up carbs. If you have the prime on for 2 minutes and fuel isn't pouring out of the over flows then fuels not getting through to the engine. Likely to be blocked filter, jammed float bowls or even blocked jets.
 
Clutches get stuck if they sit a while, Don't worry about it. Once the engine is running and oil starts moving around it should free up just fine.
 
Suzuki mad said:
If my 2002 Bandit 1200 sits for ore than a month it runs poorly with a miss fire for the first few hours, bogging down and being a real pain in the bum.

My 1981 GS1000E is even more of a pig if it hasn't run for a few weeks.

You've checked the fuel line and fuel tap (pet cock) and its drawing fuel so I would start with gummed up carbs. If you have the prime on for 2 minutes and fuel isn't pouring out of the over flows then fuels not getting through to the engine. Likely to be blocked filter, jammed float bowls or even blocked jets.
Click to expand...

where are the overflows? will the fuel just start leaking out if its on for a couple minutes?

and thanks tkent, i'll see if it works better after i get it running.
 
Went out and worked on it a bit more. I pulled the carb drain bolt on the first carb, and a lot of gas came out (more than I was expecting). So it does seem like fuel is getting to the carbs, so that rules that out.

I'm thinking my best course of action would be to drain all 4 carbs, then change the oil. If too much fuel drained down while it was on prime (I've left it on for longer than I should I think when I was thinking it wasn't getting fuel), would that cause it not to want to start?
 
The problem is likely not fuel getting TO the carbs, but fuel getting THROUGH the carbs. The passages to get fuel into the float bowls are much larger than the ones needed to get fuel to the pilot, idle, and choke circuits. Did you verify that the throttle was not being held open? You could drip a few drops of gas into the cylinders through the spark plug holes to see if it tries to start then.

Is your oil over-full? Does it smell like gas? Have you ever changed it, or is the the same oil you bought the bike with?
 
mike_of_bbg said:
The problem is likely not fuel getting TO the carbs, but fuel getting THROUGH the carbs. The passages to get fuel into the float bowls are much larger than the ones needed to get fuel to the pilot, idle, and choke circuits. Did you verify that the throttle was not being held open? You could drip a few drops of gas into the cylinders through the spark plug holes to see if it tries to start then.

Is your oil over-full? Does it smell like gas? Have you ever changed it, or is the the same oil you bought the bike with?
Click to expand...

i have not verified that the throttle is not being held open normally, but i do know that in the past when i've tried to start it, i'd hold the throttle open (first bike, used to working on cars). now i know not to do that.

I'll give it a shot putting a bit of gas into the cylinders, after i change the oil. I haven't changed it, but the previous owner said he had before sellings, and everything else he said he did (plugs, battery, etc) were all new like he said, so I believe he did it. I haven't drained the oil to see if it smells like gas, and couldn't tell if the oil level was higher. Need to pull it out of my shed so I can see, and had the battery charger hooked up. I'll see if I can check on that this afternoon.
 
No need to drain the oil, just stick your nose into the oil filler cap.
If it smells like oil, you are fine. If it smells like gasoline, you need to fix the problem and change the oil.
 
A few updates. Oil level is right in the middle, and when I smell the oil, I can very faintly smell gas, but I think this could be from when I drained the carb, and didn't have a big enough rag and a good bit of gas drained onto the case.

Checked the fuses with a meter, and all are good.

Checked the throttle, and there is a tiny bit of slack.

After I tried starting it (petcoak on run, choke fully open, not touchign throttle), I pulled the #1 plug, and this time it was wet, and smelled of gas. Thinking last time I checked it had probably been a while since I had tried to start.

So it seems like its getting fuel, so now I'm thinking spark? Plugs were all replaced by PO, and look brand new (with the exception of the black soot on the ends).
 
Assuming I'm testing spark right, its not getting there. I pulled the #1 plug, reattached the wire, and tried to start the bike and could not see a spark. Did the same with plug #4 with the same results.

Wasn't sure if it needed to be in contact with metal for a ground, so I tried both with the plug just hanging in air, and with it touching the heads, and both times, I could not see any spark.
 
It needs ground and yes, we normally lay the plugs against the head to get that. Next step will be to take your DMM and set it to 20VDC (or whatever your next step is above 12VDC), check the voltage of the orange/white wires going to each coil against the battery ground with bike ready-to-run. Also get a reading across the battery itself.

It's not a bad idea to get the impedance of the coils, both primary and secondary. Primary should be in the 5 ohms neighborhood (unplug and test across the two conductors on each coil-side plug). The actual coil secondary is normally about 14kohms, but the plug caps are usually resistor caps and add to that: 10kohms each for stock, or 5kohms each for the recommended NGK replacements. So figure 22kOhms to 35kOhms total measured from cap to cap, 1 to 4 and 2 to 3. If the impedance is very high on the secondary, the plug caps are often to blame. You can unscrew them from the wires and test individually (assuming stock coils). Cut about 1/4" off of the wire to expose fresh copper and re-install if they seem OK.

You checked 1 and 4, which fire from the same coil. You should also check 2 and 3, which fire from the other coil.
 
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thanks to your help, i got the bike running! went out to test the other plugs. #1 still didn't spark, #2 didn't either. Checked #4 again, then went to check #3, expecting no spark (since #2 didn't). #3 sparked. So then I tried plug wire #4 with spark plug #3, and no spark. So then I tried wire #3 with plug #4, no spark, and confusion. So then I tried wire #3 with plug #3, and no spark.

At this point, my mind actually started working, so I tried cleaning plug #3, and retried on wire #3 and it sparked. Pulled all four plugs and scrubbed them good with a wire brush, and hooked everything back up. Left the petcock on run, full choke, and barely hit the starter and it fired right up.

I must have just really fouled everything up with trying to get it to run (usually cranking on the throttle), and last time I had it running it only ran for a few minutes.

Plugs look brand new (no corrosion or anything), but I'm going to pick 4 more up and keep them on hand. Now to just get the clutch adjusted right, but I'll try to get it warmed up good next time I work on it and let the back tire spin a while on the center stand. Any good rule of thumb for telling when its warmed up, and I can let off the choke? I let it run for a few minutes tonight, then slowly started putting the choke back in, and it cut out. Probably just being impatient, but just glad its running :)

mike_of_bbg said:
It needs ground and yes, we normally lay the plugs against the head to get that. Next step will be to take your DMM and set it to 20VDC (or whatever your next step is above 12VDC), check the voltage of the orange/white wires going to each coil against the battery ground with bike ready-to-run. Also get a reading across the battery itself.

It's not a bad idea to get the impedance of the coils, both primary and secondary. Primary should be in the 5 ohms neighborhood (unplug and test across the two conductors on each coil-side plug). The actual coil secondary is normally about 14kohms, but the plug caps are usually resistor caps and add to that: 10kohms each for stock, or 5kohms each for the recommended NGK replacements. So figure 22kOhms to 35kOhms total measured from cap to cap, 1 to 4 and 2 to 3. If the impedance is very high on the secondary, the plug caps are often to blame. You can unscrew them from the wires and test individually (assuming stock coils). Cut about 1/4" off of the wire to expose fresh copper and re-install if they seem OK.

You checked 1 and 4, which fire from the same coil. You should also check 2 and 3, which fire from the other coil.
Click to expand...
 
Good deal. Soaking the plugs in white vinegar overnight should get them pretty clean - even where you can't reach with a wire brush.
 
cj7jeep81 said:
Any good rule of thumb for telling when its warmed up, and I can let off the choke? I let it run for a few minutes tonight, then slowly started putting the choke back in, and it cut out.
Click to expand...

Depends on the air temperature, your intake system and the state of tune. Even in cold weather after two or three minutes, certainly after five it should run and idle fine with no choke. It may idle slow for longer, but it should idle. If it won't idle you likely have some clogged passages in the carburetors, and it will be the ones associated with the pilot circuits. They are small, and they are always the first to clog up from sitting idle for months.

The passages associated with partial throttle and wide open throttle are much bigger, so they are the last to clog up.
 
Are the RPMs rising with the choke on? Mine will get to 3kRPM pretty quickly after it catches, and I have to start backing off the choke gradually. Do all the pipes get warm pretty quickly after you get it started (don't burn yourself!)?
 
mike_of_bbg said:
Are the RPMs rising with the choke on? Mine will get to 3kRPM pretty quickly after it catches, and I have to start backing off the choke gradually. Do all the pipes get warm pretty quickly after you get it started (don't burn yourself!)?
Click to expand...

yeah, the rpm's jump up, when I start it with the choke on. it would hunt around a bit last night, sometimes surging up, then calming back down. when i went to adjust the choke, i probably went too much, cut it to about half, and it would start to sputter so i'd raise it back up.

didn't check to see if all the pipes were warm, but will next time I run it (hopefully the clutch will be working and I can actually ride it). I did check both exhausts, and both were putting out about equal pressure, so pretty sure all cylinders were firing.
 
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