Help with sparkplug read.

[bexabarr]

So I have a 1981 gs750E, 16 valve engine. It starts on the first try every time with out the need of the choke. I adjusted the valves today, and the bike seems to pull a bit more. I took a few mile trip, came home... let the bike cool for a couple of hours and then pulled the plugs. Here is what I have.



There is some definite fine tunning I have to do. Any suggestions? I have never worked with the cv carbs (since my 550 has vm) and I don't want to play around with them too much, since the bike seems to be working fine. I have not vacuum synced them as I do not have the tool. Can I fine tune these carbs with out getting inside them?

Thanks for the responses...

[focus frenzy]

might want to check the vacume line for the petcock as #2 is rich, might be leaking fuel past the diaphram.

#4 looks lean but the other two look ok.

I would run a good carb cleaner through a couple tanks before messing with any settings.

[Clone]

I concur, 1 and 3 are looking not too bad, depending on your chop and riding style. 2 is rich, as suggested check the vacuum line as well as the float bowl level. 4 is a bit lean, give the adjustment a half turn. Run through two consecutive tanks of gas with half a can of seafoam in each. Then one more tank of just gas then repeat your chop.

[bexabarr]

Hey guys... I checked the petcock and I think it's leaking down the vacuum tube. It's dark out so I can't verify it 100%. For 4, I assume it is 1/2 a turn in. My old VM carbs had both an air screw and a fuel screw and don't know if that is the same case for these carbs. Thanks again .

[renobruce]

You only have a pilot fuel screw... no side air screw.

[bexabarr]

ah ok... so I would have to turn it half a turn out then to richen number 4, right?

[chef1366]

Get a new petcock. Plug reads don't just reflect the idle mixture screw since most of your driving is on the needle circuit. Do plug chops with clean plugs with a new petcock.

[Steve]

Run through two consecutive tanks of gas with half a can of seafoam in each. Then one more tank of just gas then repeat your chop.

I agree with the idea of a strong mixture of SeaFoam to clean the carbs, but will offer this caution:
I would not leave the strong mixture in overnight.

My suggestion is to go for a llooooonnnnnggggg ride. \\/
Pick a destination about one full tank away. Not sure what size your tank is, or what mileage you get, but 200 miles should do. Put half the SeaFoam in, fill the tank, go for your ride. Go at least until you hit RESERVE before you turn back for home. Put in the other half of the SeaFoam, fill the tank, but leave it on RESERVE for the next hour or so to get the RESERVE passages clean, too. When you get home, fill the tank to dilute the mixture, then go at least around the block to get the diluted mixture into the bowls before parking it for the night.

Next morning, when it is cool, put in the new plugs and do your plug chops to see if it made any difference.


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