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Running lean with sooty plugs

  • Thread starter Thread starter badeaslava
  • Start date Start date
Looking forward to seeing your plug chops (pictures if possible). That is really going to be the best way to see what is going on.

For my own clarification, why do you say that the "stock" main jet size was #110? Where did that number come from? It is listed as 97.5 on all of the charts/manuals I can find online. The 110 on the website you mentioned is on a 650GL.
 
THank you for all your replies, i apologize i didn't mean to waste your time just trying out different jet sizes and willingly ignoring the service manual data. So the reason i think my bike had 110 stock mains is because that's what it had when i purchased it, with the stock airbox and everything. THe bike is 650EZ from 82, i searched online and couldn't find anything on the forums stating the exact jetting for this model bike. A different forum states the jetting for the GZ/GLZ 650 of the same model to be #110 i figure the only change from the G to E is the chain drive but the engine shouldn't have changed.

http://www.thegsresources.com/_foru...3-Carb-OEM-specs-as-per-factory-manuals/page2 (its in Eliseo Monteverde;s post)

I suppose there's a slight chance that the previous owner swapped the stock carbs on my bike with carbs from another model but it's very small. THis is why i was using #110 mains as my gold standard.

I will try though swapping 105 in there and running just on idle and reporting back what i get. I'll have to order those jets though since i dont' have them anymore, so that will take a little bit of time for shipping.

Joe, i checked float heights both on emptied bowls and using a bench method with a clear tube with the bike running. THey seem to be all within spec. I guess what worries me more is the hanging rpm that was there on the bike the entire time, even with the stock airbox, which seems to be contradictory with the running rich issue. But i'll try to sort out the sooty plug issue before i handle the hanging rpms.
 
Is this not the bike in your signature?

You are now confusing me, it's not usually quite that easy.

badeaslava said:
THe bike is 650EZ from 82, ...
Click to expand...
yet, your sig says it an '81 650E.

Which is it? :-k

It won't change the jetting needs any, just trying to keep things straight.

.
 
Steve said:
Is this not the bike in your signature?

You are now confusing me, it's not usually quite that easy.


yet, your sig says it an '81 650E.

Which is it? :-k

It won't change the jetting needs any, just trying to keep things straight.

.
Click to expand...

it's the same bike Steve, i must have entered the year in my sig incorrectly, its the 82 model with the designation Z, so it's EZ.
 
OK, but now you should be aware that saying it's an '82 ... Z is redundant. :-k

The denizens of this forum and the geekiest parts monkeys are probably the only ones that understand the Z at the end.

Most everybody else will understand "1982 GS650E". :encouragement:

.
 
So i've finally gotten around to do a spark plug chop test on my bike per all of your suggestions. I installed 105 main jets on the bike and cleaned the sparkplugs with a brass brush practically before each plug chop test. The plugs are new, i just bought them they just get fouled with unburned fuel very rapidly so i have to clean them to see what's what.

This is with 2.5 turns out on the idle mixture screw and 105 mains. After 5 mins just idling the plugs were very sooty. After about 1/2 throttle on an uphill for maybe 10 sec, the plugs were sooty still. After wide open throttle for about 10 sec, the plugs looked clean, with very minimal carbon deposit. So i figured it's gotta be the idle mixture, so i turned down the mixture screw to 0.75 turns out and went up to 115 main jets (what i had lying around) and it seems like a miracle happened. The hanging rpms disappeared, the bike doesn't die on stop lights anymore and holds a 1100 rpm idle quite well. At about 1/2 and on throttle the engine looses power from what seems to be a lean burn, so i was thinking to increase the mains to 117 (like in a previous post by member GSX1000E) I rode the bike yesterday for about 20mins and pulled the plugs, they are still a little sooty, but much better than before, maybe i have to turn in the mixture screw some more.

Another new update is when the bike is idling and i pull the choke out, it dies. Why does that happen? Is the engine instantly just flooded with too much gas from the choke circuit?

So what do you think i should do for the idle jet, clearly i need to decrease it, unfortunately i have no idea which one i have in there right now. The factory manual says 42.5 should be in there, is there any way to check, wire gauge?? If i were to decrease it would i go down 2 sizes? Should i mess with the idle air jet at all? it's 160 right now.

I think the fact that i'm still running lean with 115 mains confirms the fact that my stock mains were 110 as opposed to 97.5 (as in the factory manual).
 
badeaslava said:
After wide open throttle for about 10 sec, the plugs looked clean, with very minimal carbon deposit.
Click to expand...

So, with Wide Open Throttle (WOT) for about ten seconds the plugs are clean? Right? So, the 105 Main Jets are spot on...Doh!

attachment.php

So, now is the time time to put that #105 main jet back in because it is the only circuit operational at wide open throttle.

Now it is time to adjust the Pilot Air Screw in ONE carb when the bike is warm. Adjust that Pilot Air Screw until the one carb's spark plug is nice and clean at idle. Measure the turns...CAREFULLY by doing 1/4 turns to seat the Pilot Air Screw. Use that setting for the other three.

Now you have the Idle and the Wide Open Throttle set with the #105 Main Jets and the correctly determined Pilot Air Screws for your Idle.

So, the only thing left is the Mid-Range which is controlled by the raising and lowering of the Needle.
 

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I suppose I'm confused then Joe, with 105 mains the bike wasn't pulling at all at WOT, like the engine just turned off after a point. I thought that's a sign of a lean mixture, unless you think that my needles are just set to really lean. I don't think that 10 sec at WOT would result in white burned plugs, am i wrong? Even at 115 mains it pulls much better than with 105 but still there's a point after which seems like the engine just turns off.
 
So I missed that data point (with 105 mains the bike wasn't pulling at all at WOT), I read that they were no long sooty, just pretty clean.
 
So i put the bike in for storage for the winter, I checked the clearances in the middle of the summer though and bought some shims to get them within spec, they should be good.

On a somewhat unrelated note, maybe someone can shed some light on this issue. My bike seems to start much easier when i do a rolling start than when i use the starter. Why is that? I jump started the bike from my car's batter one time and it just didn't want to fire, while when i roll started it, it fired up much easier. I did have my car running when i was jumping it which i NOW know i'm not supposed to do.

I'm just curious on this issue since i don't understand the mechanism why that should happen.
 
badeaslava said:
On a somewhat unrelated note, maybe someone can shed some light on this issue. My bike seems to start much easier when i do a rolling start than when i use the starter. Why is that?

I'm just curious on this issue since i don't understand the mechanism why that should happen.
Click to expand...
When you push the starter button, the starter requires a LOT of current from the battery. If the battery is not quite 'up to snuff', there will simply not be enough left over for the coils to fire the plugs. When you bump-start the bike, you do not have the draw of the starter pulling the voltage down in the system. Put a voltmeter across the battery terminals, note the voltage, it should be in the 12.6-12.8 volt range, depending on the type of battery you have. Turn the key ON (but don't do anything else yet), the voltage should stay above 12.0, and will be dropping slowly. Push the starter button, ideally, voltage will not go below 11.0. If it goes below 10.0, it's time for a new battery.

You should also note that with properly-adjusted valves and carbs, it should not take more than one second of button-pushing to get the bike running.
 
Steve said:
You should also note that with properly-adjusted valves and carbs, it should not take more than one second of button-pushing to get the bike running.
Click to expand...

When mine starts to get near a second to catch, I'll start to look at things to find out why. Immediately after I did the shims and sorted out the carb at that point, it was starting first touch of the button, but has gradually fallen away from that. However, knowing how good it can be, is a useful benchmark.
Latest hassle was a starter with stuck brushes, and the temporary one in there at the moment is a little bit of a slow performer, so totally rebuilt starter is on the cards.
Another thread topic...
 
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