Bowl levels are the same, sooooo.....

[DaveDanger]

ditto that remark on anti-seize scud... you don't want anything that seals the threads permanently, but something that lubricates them a bit so that they turn in and seat more firmly with the same amount of torque. I'm sure Loc-tite? makes a product, but it won't be called Thread Locker. Permatex and 3M both make great products also.. I use one by the product name of C5-A, but I'm danged right this second if I can think who makes it. Looks like a heavy copper powder in a thick oily base. I have yet to find anything on a turbocharged aircraft engine that will bake it off a bolt or stud. I put a small dollop on every spark plug just before I install it. Just make sure that its only on the threads, any brand. Anti-seize generally has a metallic base and will short the hot electrode as surely as a chunk of carbon.

[Scud]

Thanks Dave - but I am still taking them in and out frequently and figured that I would wait to do that when I have the jetting and other issues resolved.

gsBert - sorry... :? I now better then to loc-tite them in there..

I took her out for a twenty-five mile ride, pulled the plugs and all looked as if they were new....with the exception of number two...it looked perfect...light tan. I did switch coil leads from three to two and two to three before this ride.

I will tell you that I did, last spring, buy an Emgo replacement air filter, it seemed like a lighter duty filter (can almost see through the paper element!). I just put the OEM filter back in to see if maybe it would restrict the flow a little and make her run a little richer.

It is snowing to 6,400 feet, I live at 6,200 feet....not sure when I will get chance to ride again but will let you know what I find out.

Scud

[DaveDanger]

Scud, every time those plugs thread in and out is another opportunity for the threads to gall and seize. Frequent usage is exactly why I want anti-seize on my plug threads.

[KEITH KRAUSE]

Scud, just to make sure, your latest plug reads are after you plugged the vacuum port at carb #2 and ran the bike on prime, correct? Nothing else was done?
If this test was done correctly and the dark #2 plug became a perfect tan, then this result would suggest the petcock is leaking through the vacuum tube. Most likely if you rode it even longer, the remainder of the previous soot build up would burn off and the plug would probably lighten more, though further lightening of the plug isn't guaranteed.
As for this part of your problems, you can probably accept that the petcock needs a new diaphragm/rebuild, but if you want to be 100% sure, test it one more time with the vacuum re-attached normally and the petcock turned to "on" again. Since this would be the only change, if the #2 plug darkens again, it's positively the petcock. I only mention this double check in case theres ANYTHING else that could have been done or happened to make that #2 plug lighten up to a tan color.
After rebuilding the petcock, you can then take some solid 1/3 throttle tests for a mile or two (if you can do this safely) and do what the plugs say to. Full throttle for the mains. Minimal throttle position to test the pilot circuit, say 35 mph in 4th gear/steady.
These three tests will tell you how the three jetting circuits are mixing. Even with todays cleaner burning fuels, you need to see at least a "grayish" color on the insulator, tan/gray even better.
By the way, anything you notice about the performance? "Cold-blooded"? After completely warmed up/hot and in neutral and idling correctly at close to 1,000/1,100 rpm, if you rev the motor do the rpms seem a little slow to return to that idle speed? Do you notice any surging or light hesitation, almost like driving into light wind gusts, at steady cruising speeds? With the bike hot and in a taller gear, say 4th or 5th going about 40 mph, if you opened the throttle at least 1/2 way or more going uphill, do you get ANY pinging? Pinging on a bike can be more subtle than the "marbles in a tin can" sound you get from a car. Sometimes it just sounds like a clicking sound, very fast. What average mpg are you getting?

[Scud]

Dave - thanks for the advice about the anti-seize, I will look into it.

Keith - Yes, the latest reults were with the vacuum tube plugged and on prime. I will do the '100% for sure' test once the snow melts off the road (should be this afternoon sometime hopefully).

As far as cold blooded and warmed up, no, the performance is the same. There is no hesitation or sluggish return to idle when revved. Idle returns to 1,100-1,200 (see below). The ride I took was up to Grand Targhee a ski resort so all of it is uphill with a few switchbacks. So when I was going 40 or so in 4th or 5th gear there was no hesitation, it pulled fine when I rolled on the throttle.

As far as pinging goes, I did not notice any if there was any, but if it is as subtle as you say then I need to listen closer next time, but it did not seem so.

I am averaging around 40 to 45 miles per gallon.

When I returned to my garage after the ride the idle was about 500 RPM higher then when I left. Does this tell you anything?

Scud

[KEITH KRAUSE]

OK. Just trying to mention some symptoms of a lean mixture. You passed those questions, but the bike shouldn't pick up 500 rpms from cold to hot. I'm not positive what would be considered a good cut off point but about 100/200 rpm gain could be acceptable. Beyond that, in my opinion, this shows a lean mixture or an intake leak or mechanical problem such as sticking throttle plates, diaphragm/spring assembly or your mechanical advance unit is sticking a little with the heat build up.
A lean mixture effecting the idle quality that much isn't very common. An intake leak is the most common cause, followed by the other ideas.

[gsBert]

hey scud: hang in there...

youre almost done solving your problem... leaky petcock seems to richen plug 2 unless it wasnt in right...

speaking of plug chops, im gonna do some on my 1150 tomorrow, but i ran into a snag...

i can do the 1/8 aqnd 1/2 throttle for 10-15 second run easy enough (i got 3 sets of new plugs with me on the trip to make sure i get good reads).

but the full throttle run is gonna be real dangerous... i mean, think about it, full throttle for 15 seconds in fifth gear.... where on earth am i gonna find enough road to do that? and a place to pull over (clutch in and ignition off) to yank the plugs and look at them...

i have a straight level stretch of expressway i can try this on, but i'm pretty sure the authorities wil frown on the 260km/h sppeed i am sure to reach.... at least i installed a windshield on the bike so i wont get any helmet lift...

in any case, its been nice knowing you, if you never hear from me again, you'll know what happened....

i might also smarten up and go to see this guy who has a dyno in his sound insulated garage.... 60$ for 4 runs...

do you know anyone like that scud?

by the way, my offer to trade your 750 carbs for mine still stands you know... but i think your problem lies elsewhere...

if you do trace it to the carbs though, lets trade and while i have yours i will fix them. if you dont want them back, just keep mine...

my engine is a 1981 16v 750 with the stock carbs. i use a '82 1100 airbox (same) and chassis

[beby99]

I put a small dollop on every spark plug just before I install it. .

Hehehe.. Had to lookup what a dollop was:

Table of Uncommon Conversions

2 pinches = 1 bit
4 bits = 1 smidgen
2 smidgens = 1 dollop
3 dollops = 1 gaggle
1 gaggle = 2 glugs
2 glugs = 1 blanket
3 blankets = 1 smothering

Sorry

[DaveDanger]

Alright, now I'm beginning to wonder if my West Texas heritage has let me down. I also measure out some items in a "skosh". As in "Pull that Carb-set a skosh more on your side!". Didn't even see that one on your table of measures...

[beby99]

Between you and the Aussie's I'm going to need a
new dictionary

[mixongw]

Alright, now I'm beginning to wonder if my West Texas heritage has let me down. I also measure out some items in a "skosh". As in "Pull that Carb-set a skosh more on your side!". Didn't even see that one on your table of measures...

You are talking linear measurement here... One skosh equals two RCH.

[Scud]

gsbert - unfortunately I do not know anyone with a Dyno...I live about 70 miles from the nearest big city and may go that way if I cannot figure this out.

But I am persisitent 8)

Be careful....I need your advice, could you wait to do your plug chop until I have my problem figured out

Keith - I thought it strange also that the RPM's would climb that high, it was an estimate as far how much it went up, it may have been only 200. I will check it out next time I ride.

Temp is currently 37, may wait a little to see if it warms up before taking bike out for a spin/diagnose session.

Another question....I ride through temperature swings of up to 50 degrees at times, would that contribute to my problem with the plugs and condition they are in at certain times of the day?

Thanks guys,

Scud

[gsBert]

no, temp/altitude wouldnt affect it much scud, that's the beauty of cv carbs....
did my plug chops, posted about them, was careful. thanks for the concern.
im running lean

[Scud]

thanks bert, glad to hear that you are ok....


ah yes...running lean, I know all about that :?

Scud

[Hoomgar]

I use one by the product name of C5-A, but I'm danged right this second if I can think who makes it. Looks like a heavy copper powder in a thick oily base.

I believe that is also a Permatex product.

I will tell you that I did, last spring, buy an Emgo replacement air filter, it seemed like a lighter duty filter (can almost see through the paper element!). I just put the OEM filter back in to see if maybe it would restrict the flow a little and make her run a little richer.

AHA! That air filter could be a big contributor to your lean issue. If you can (sometime when it doesn't interfere with any of the tests Keith has suggested for that rich #2 plug) try a run and plug test with a stock air filter put back in. I am now willing to bet on this one. Bad pipes, bad air filter. A combination problem like I have been saying all along. These two critter combined can definitely give you a lean condition that carburetion tweaking wont get rid of. When you get a chance, I would definitely check/test this. You fixed the pipe, this renegade air filter may be the remaining missing link. Here is to hoping it is!