Hard to start and pinging under load

[Craig54]

Hi
1981 Gs1000g

I have always had trouble starting this beast and always thought it was the starter motor.
It sounds like the ignition is too advanced and it is igniting on the way up.
I also noted it pinging upder load on a steep hill.

Any ideas?????

Craig54

[tkent02]

Hi
1981 Gs1000g

I have always had trouble starting this beast and always thought it was the starter motor.
It sounds like the ignition is too advanced and it is igniting on the way up.
I also noted it pinging upder load on a steep hill.

Any ideas?????

Craig54

I have an idea. It sounds like the ignition is too advanced and it is igniting on the way up.

[Nessism]

Carb jetting may be too lean as well. Header/pods will do that or plugged up carb jets.

[TheCafeKid]

What kinda gas you putting in it? If youre using a premium (anything above 87 or 89) STOP. Its not better for the bike (in STOCK configuration, or slightly modified) its worse.

[Flaggo60]

What kinda gas you putting in it? If youre using a premium (anything above 87 or 89) STOP. Its not better for the bike (in STOCK configuration, or slightly modified) its worse.

Always thought that premium gas would not cause additional problems in a lower-tuned motor, just that the advantages offered by premium would not be realized and the extra cost would be wasted.

[Nessism]

Always thought that premium gas would not cause additional problems in a lower-tuned motor, just that the advantages offered by premium would not be realized and the extra cost would be wasted.

Agree, although some people claim to have other problems.

[dardoonk]

I have an idea. It sounds like the ignition is too advanced and it is igniting on the way up.

Had the same idea myself. Have you checked your timing?

[Craig54]

Hard to start and pinging under load

Timing is the first thing I thought of but isnt the ignition electric and not adjustable?

[Steve]

I have always had trouble starting this beast and always thought it was the starter motor. ... Any ideas?????

Just one idea. When is the last time you checked your valve clearance?

Not starting, especially when cold, is a classic symptom of tight valves.

Always thought that premium gas would not cause additional problems in a lower-tuned motor, just that the advantages offered by premium would not be realized and the extra cost would be wasted.

Just what are the 'advantages' of "premium" fuel?
- It has fewer BTUs per gallon (this means less power per gallon)
- It burns slower
- It is harder to light

Yes, higher-powered engines require the use of "premium" fuel (let's just call it high-octane fuel, OK?, there's really nothing "premium" about it except the price), but it's not the fuel that gives those engines their power. You get more power with higher compression. You can get higher compression by squeezing the mixture tighter with different pistons or possibly by changing the cam timing a bit to optimize cylinder filling. Either way, you end up with a tighter mix. Compressing air raises the temperature. Rasing the compression ratio raises the temperature even more. If you compress it enough, it can actually get hot enough to light the mixture before the spark plug lights the fire. Higher-octane gas is harder to light, so the mixture won't light until the spark sets it off. Higher-octane gas also burns slower, so you have to advance the ignition to start the fire soon enough to have it burned completely in time to push the piston down. So, you can see that "premium" fuel and advanced timing are really band-aids that let you take advantage of your higher compression.

If you use high-octane fuel in a normal engine that does not require it, it will not be burned completely in the combustion process because it burns cooler and slower. This can end up leaving deposits on the valves or pistons. Since there are fewer BTUs per gallon and you require a given number of BTUs to get down the road, you will have to use more gas to do it. Therefore, not only are you paying more for each gallon of gas, you are using more of it, too.

Too many guys will put high-octane in thinking it gives them more power, and also bump ignition timing to do the same thing, but what they are really doing is giving the engine enough timing advance to light the gas to almost restore normal power on the more-expensive gas.

.

[terrylee2u]

Ok.. the price to fill mine up just got cheaper...

[Steve]

Note that if you have been running high-octane gas unnecessarily, you might have deposits built up in the cylinders. If you switch to regular gas, these deposits might retain enough heat to light the mixture, leading to "pinging". If a timing check shows that things are OK there, you might need to run a mid-grade gas to keep the pinging under control. These deposits might clear up over time, but might need to be removed mechanically. That means you will have to remove the head and scrape them out.

.

[Nathan Daube]

I thought the timing was a nonadjustable for the most part as well. After replacing the leaking head gasket I removed the right side cover on the crank and way back on the ignitor plate is a timming mark. It is adjustable and even using an old light (the kind that goes inline with the sparkplug wire, not and inductive one) I was able to adjust the timing and the bike is running alot cooler and better than before. P.S. the Head gasket was just leaking oil from the camchain, not a compression leak.

[Nessism]

Note that if you have been running high-octane gas unnecessarily, you might have deposits built up in the cylinders. If you switch to regular gas, these deposits might retain enough heat to light the mixture, leading to "pinging". If a timing check shows that things are OK there, you might need to run a mid-grade gas to keep the pinging under control. These deposits might clear up over time, but might need to be removed mechanically. That means you will have to remove the head and scrape them out.

.

The '81 1100 has mechanical advance so it might be sticking. You should be able to rotate the rotor on the crank end, when you release it the rotor should snap back smoothly.

Steve,

Do you have some information that shows that premium gas will create deposits? I've never heard of this issue other than from you. Please educate me.

[SqDancerLynn1]

When I had problems with my 850 pining, A new set of carb boots fixed the problem. So check your boots & O rings

[chef1366]

If you have a timing light you can set the timing with the ignition plate. It does rotate. Do it at a low idle. Get on the throttle and make sure the advance mark also lines up to check the advance.
Lynn has a point about the possibility of running lean.