Why does my bike hate me? (Misfire)

[CirclesCenter]

Alrighty ladies and gents.

Bike is misfiring, and to make our problem more entertaining, it seems to be intermittent.

I have tried both PRIme and ON. No difference noticed.

Only does it under load.

I put 91 octane in every time.

HELP!!!!!!

[annguyen1981]

Unless you've got performance mods, only use 87 octane.  Why spend extra $$$ for nothing?

[CirclesCenter]

To try to avoid this.

[annguyen1981]

To try to avoid this.

Avoid what?

[CirclesCenter]

Having any problems, hoping that even if I do end up with not so great gas (might be the problem?) at least it's the best gas they had at that station.

[annguyen1981]

Depending on the engine, sometimes getting the higher octane fuel does slight harm to the engine.

[melloGS]

i don't think 93 octane can hurt any engine...maybe 100+, but not 93...

[annguyen1981]

Sorry for the misconception...  When I meant bad for the engine, I really mean things like lowered gas mileage is possible, or slight knocking (maybe)

[Alphamazing]

Sorry for the misconception...  When I meant bad for the engine, I really mean things like lowered gas mileage is possible, or slight knocking (maybe)

Knock is caused by too low of an octane gas. The gas pre-detonates or pre-ignites in the engine due to either pressure or heat or a combination there of, thus causing a knocking sensation. It also has to do with flame travel and interference, but I won't go into that. Higher octane gas prevents all this.

Here's a good picture:

[Yankee Punker]

 What year is your bike?  How many miles?

  When was the last time you've..... 
   
    Checked your valves clearance?
    Cleaned your carbs?
    Checked your throttle cable/carb sync.?
    Checked your spark plugs?
    Hows your voltage when running, and off?

  Just some suggestions.  And 91 octane is overkill, the GS does not have that high of compression for 91, it doesn't hurt it, but is just wasted money. I switch between reg. and mid-grade about every 150 miles, so I'm probably running about 88.

[deathlucky]

wtf i use 95 octane because it is the cheapest

[Yankee Punker]

wtf i use 95 octane because it is the cheapest

What's the octane level of the most expensive?

And what's the compression ratio of your auto's there in Australia?

[deathlucky]

lowest is 91 or 92 highest i have seen is 98

[Alphamazing]

wtf i use 95 octane because it is the cheapest

What's the octane level of the most expensive?

And what's the compression ratio of your auto's there in Australia?

They have a different method for measuring octane than we do, same as Europeans.

Wacky foreigners! 

[The Buddha]

If it wasn't doing it before and ... You did any new mods or any thing at all ... that's what fooked it up.
If you didn't do any mods or maintenenace - OK that's your problem ... it needs maintenance - airfilter, jetting, water in fuel, bad electrical connections ... whatever ...
Now if all that is good, and you're still having this ... Toss the damn NGK spark plugs out and put in champions. Serious.
Cool.
Srinath.

[NiceGuysFinishLast]

It hates you cuz you dropped it. Duh.

[natedawg120]

If it wasn't doing it before and ... You did any new mods or any thing at all ... that's what fooked it up.
If you didn't do any mods or maintenenace - OK that's your problem ... it needs maintenance - airfilter, jetting, water in fuel, bad electrical connections ... whatever ...
Now if all that is good, and you're still having this ... Toss the damn NGK spark plugs out and put in champions. Serious.
Cool.
Srinath.

thats it.  Change electrical compontents in order or cost starting with the plugs, then wires.  Also check the coils to make sure they have a good connection and theres no corrosion in there. 

[ignoreance]

List stuff done to bike?

[CirclesCenter]

Only the forks have been porked around with, the engine (to my knowledge) is stock.

Pulling plugs after I lay down for a bit, I'm so beat......

[ignoreance]

And the bike I'm guessing is new...  Don't know