over revving 79 gs400

[woodytwoshoes]

Forgot to mention the plugs are very black and sooty as well.
Woody

[Nessism]

Forgot to mention the plugs are very black and sooty as well.
Woody

What does this mean Woody? Over reving as in exceeding redline - 10,000 rpm? A hanging idle due to poor maintenance? Something else?

[woodytwoshoes]

overrevving

over-revving as in going from idle to wide open without the throttle being used.
Woody

[Flaming Chainsaws]

Air leak, kinked throttle cable, idle knob not adjusted properly, dirty carbs?

It could even be the "choke". Whenever you use the choke, the RPM will rise very high. Right at that instant, you adjust the "choke" lever so that it will idle around 1,500 RPM - 2,000 RPM.

Of course I am only guessing. Explain this problem a little better.

Sparkplugs are black and sooty? It's running rich (choke?)

[woodytwoshoes]

carb issues

Ok, no air leaks, checked with starting fluid spray. throttle works freely, i just redid the float settings, im about to put them back on, ill keep ya informed.
Thank you
Woody

[BigD_83]

Ok, no air leaks, checked with starting fluid spray. throttle works freely, i just redid the float settings, im about to put them back on, ill keep ya informed.
Thank you
Woody

Just because the throttle works freely doesn't mean it has the correct tension or routing.

Make sure you have SOME free play in the throttle (I think the spec is something like 1/8 -1/4"). If not, open up the right hand control and sneak a peak at the cable routing. It could look like this and still feel okay:

http://www.thegsresources.com/_forum/showthread.php?p=1282556#post1282556

Specifically post #41

[woodytwoshoes]

over-revving

well the carbs are back on and still the same thing. I moved the clip on the needles up one notch to lean it and plugs are still black and she revs way up without throttle being turned.
Throttle mech is working fine, hmmm im at a standstill for now. Not sure what to check next.
Woody

[Steve]

well the carbs are back on and still the same thing. I moved the clip on the needles up one notch to lean it and plugs are still black and she revs way up without throttle being turned.
Throttle mech is working fine, hmmm im at a standstill for now. Not sure what to check next.
Woody

OK the plugs are still black, but which carb circuit did you test?

The needles only affect mid-throttle, and I'm talk throttle setting, not RPM.

You need to do proper plug chops (<-- click link) to test each circuit of the carb to see how it's running.

The guide in the link is for the VM carbs, but the concept is the same. Test each circuit at its particular throttle setting, "chop" the ignition, pull the clutch, coast to a stop. Examine the plugs. Repeat for next carb circuit, etc. THEN let us know what you find.

If possible, start the test with a fresh set of plugs. When you get it all sorted out, you can put your current set of plugs in there and they will clean up just fine, so you will be set for quite a while, as far as spark plug go.

.

[BigD_83]

well the carbs are back on and still the same thing. I moved the clip on the needles up one notch to lean it and plugs are still black and she revs way up without throttle being turned.
Throttle mech is working fine, hmmm im at a standstill for now. Not sure what to check next.
Woody

Hey Woody,

did you actually open up the throttle to look inside? I'm asking this from experience. It may work "fine", but that still doesn't mean the cable is properly in the guide slot.

Do you have any freeplay of the cable at the carbs?

What you are describing sounds like the carb throats are open too much...

[woodytwoshoes]

over revving

Ya, carb throats. How are they adjusted? The needles seem to go down and bottom but there is still a big gap between the bottom of the plunger and the throat of the carb. ???????
Help
Woody

[BigD_83]

Ya, carb throats. How are they adjusted? The needles seem to go down and bottom but there is still a big gap between the bottom of the plunger and the throat of the carb. ???????
Help
Woody

Yes, there will still be a "gap". Not sure how much of one is too much. I need to clarify what I wrote before as I seem to have sent you astray. I didn't actually mean for you to look at the gap at the bottom of the slider...I meant that the butterfly sounds like it is open too much. This could be due to the idle adjust being way off, a bad bench synch, or the throttle cable pulling it up.

What part of the Great White North are you in? I'd be happy to provide another set of eyes for you if you are in the Vancouver area.