Troubleshooting help - sudden loss of power

[Roostabunny]

Here's a closeup of the #1 plug this morning. It's not brand new - it's the one that used to be in cylinder #2, which is a BP7ES. I put the new 8 plug in the #2 spot.

Anyway, it's developing a shiny black glaze on the electrode tip (less shiny on the rim and ground strap), just like the first.

[tkent02]

Here's a closeup of the #1 plug this morning. It's not brand new - it's the one that used to be in cylinder #2, which is a BP7ES. I put the new 8 plug in the #2 spot.

Anyway, it's developing a shiny black glaze on the electrode tip (less shiny on the rim and ground strap), just like the first.

Your camera focused on the inside of the spark plug socket and not the area we need to see, but it's starting to look shiny like oil. What does a new plug of the correct heat range look like after 100 miles or so?

[TheCafeKid]

Bro. If you take that plug out, and it dries, its gas. If it doesnt dry, its oil. Simple as that. I know you dont want to imagine that its oil, but it certainly looking that way to me as well.

[Roostabunny]

Your camera focused on the inside of the spark plug socket and not the area we need to see, but it's starting to look shiny like oil. What does a new plug of the correct heat range look like after 100 miles or so?

Augh! So hard to photograph. I bought 4 of the standard plugs, so I'll check the gap and install one tonight in #1 and I'll have 100 miles on it in a couple of days and try again with the camera.

Bro. If you take that plug out, and it dries, its gas. If it doesnt dry, its oil. Simple as that. I know you dont want to imagine that its oil, but it certainly looking that way to me as well.

OK, that's what I figured. This stuff is absolutely dry, but I wouldn't describe it as "fluffy" as I've heard carbon described on some of the plug sites. I thought oil should stay goopy and, say, scrape off with a fingernail? This deposit will scrape off with a blade, but with the shineyness I figured it was "baked-on" oil.

You're right - I don't want it to be oil. :-D But now that I know my compression's OK, I'm only mildly intimidated by the process of removing and replacing the head, but the problem is...

1.) I don't have my own shop where I can tear the engine apart for a couple of days. Valve adjustment is about as deep as I'd want to get in the space I have.
2.) I already have a set of o-rings to rebuild the carbs and can easily do that in the space in my little detached apartment garage.

Anyway, no biggie. I panicked, got over it (thanks for putting up with my therapy post), then got compression numbers that were reassuring. Now I just want to know what's actually happening so I can get the grin back. After all, if it is oil, then I get to say sayonara to my weepy base gasket sooner than I planned.

I'll ride on a brand new plug for a couple of days (100mi per Tkent02's advice), and I'm pretty sure I'll have the evidence by then.

[KEITH KRAUSE]

Bro. If you take that plug out, and it dries, its gas. If it doesnt dry, its oil. Simple as that. I know you dont want to imagine that its oil, but it certainly looking that way to me as well.

Same thing I said before. If there's still a sheen once dry, it's oil. Carbon doesn't shine or look glossy.
Oil will also smear, at least a little, if wiped on a mirror. Carbon isn't an oil.

[twistedwankel]

[/quote] Now I just want to know what's actually happening so I can get the grin back. After all, if it is oil, then I get to say sayonara to my weepy base gasket sooner than I planned.

I'll ride on a brand new plug for a couple of days (100mi per Tkent02's advice), and I'm pretty sure I'll have the evidence by then.[/quote]

You still have a sticky slide valve. Your plug looks just like mine did before I got the slide working properly again. I now have that from two different sources besides my own experience. Minor grime left over from your air box crumbling?

[Roostabunny]

OK, so when it rains it pours...

Having decided to replace my shocks, I suddenly lose power. Halfway through troubleshooting that, I spring an oil leak bad enough to drip on the pipes and send up a minor bike-B-Q haze by mile 20.

At first glance, the leak looks like my tach gear/seal. I'm puzzled because I replaced that seal this fall. Maybe I'm paying the price for not replacing the gear when I replaced the seal?

Unless somebody thinks this oil leak could be connected to my loss of power, I'll get the leak diagnosed and sorted and then I'll be back once I finish fouling the new plug.

[Roostabunny]

[/quote]You still have a sticky slide valve. Your plug looks just like mine did before I got the slide working properly again. I now have that from two different sources besides my own experience. Minor grime left over from your air box crumbling?[/quote]

So how'd you free yours up?

[jabberjoe87]

from it ideling fine and there being loss of power on acceleration, are you sure that your jets dont have durt in them? my 77 gs 750 did that a lil bit ago and i cleaned them out and have not had a problem since

[chef1366]

Check the valve cover bolts. Are any loose? Is it the head gasket? Could the leak be from a crankcase cover? Get five or so cans of brake cleaner and clean all the oil off the bike and idle it till it get good and hot and find the oil leak. Keep an eye on the cam chain tensioner also and the long cylinder studs that run it between the gaps in the cylinders.
Were your carbs cleaned and all o-rings replaced?
Do you smoke at all when cold with full choke? This is a sign of bad valve guides or valve stem seals but it could also be rings. If you really goose it does it blow smoke?
Sounds like you need to get to know your bike and figure out what's wrong with it cause this thread is all over the place with it's advice. Not the fault of the posters but the lack of being there to see and hear the bike in person.

[TheCafeKid]

K. You have a new set of problems on your hands. To me, to be perfectly honest, and *I* dont even like saying it, but it sounds like your best course of action, since you all of the sudden have a compounding series of problems involving oil in one way or another, is to take the head off, replace your gaskets, replace seals, maybe even the rings, and then you will KNOW that you likely have solved multiple problems in one shot.

Trust me, i know where you are at with it. WHen i first bought my 750, i wanted to try anything and everything short of doing what, in my heart, i knew needed to be done.

One other thing to consider however, if you find that the plug is covered with carbon and GAS and NOT oil, check your float levels. Check your float valves. Replace as necessary, even if you have a guess that one is bad. I went nuts with the 750, getting crossed readings. Two cylinders said lean, which made sense to me as the bike prolly had never been jetted by the PO for the pods and pipe, and two cylinders (the 2 and 3) said rich. The exhaust smelled rich. It just didnt make sense to me for a bit, untill i tore my carbs down to clean and rejet, and EUREKA! the two inside cylinder's carbs float levels were STOOPID off, allowing fuel into the crankcase, making it run like ass, and giving me crossed readings. The two cylinders were getting WAY too much gas. Plugs were wet, carboned up badly, and i too feared it was oil. But alas this seemed to be the problem.

Press on, you shall succeed if you dont let IT beat you. :-D

[twistedwankel]

You still have a sticky slide valve. Your plug looks just like mine did before I got the slide working properly again. I now have that from two different sources besides my own experience. Minor grime left over from your air box crumbling?[/quote]

So how'd you free yours up?[/quote]

If you have a couple small mirrors on a stick you might be able to see the slide move under throttle revs to avoid taking more than the air cleaner out. #1 and 4 are hidden from view - your luck being the same as mine. Obviously they all should move at the same time and the same height.

When you had the spring out you could have gently moved the slide up and down to see if there was any drag on it. Otherwise I think you'd have to pull the guts including diaphagm out and clean it. Fortunately, I didn't have to do that. Once free mine stayed free. I was told it doesn't take much dirt/material to get them stuck. In my case the spring itself was the major culprit binding it. Hope you get off easy like I did. I was sure I'd end up having to get the carbs cleaned (dread) but they are fine - in part due to running 1/2 a can of SeaFoam thru the last tank of gas.

[Roostabunny]

Check the valve cover bolts. Are any loose? Is it the head gasket? Could the leak be from a crankcase cover? Get five or so cans of brake cleaner and clean all the oil off the bike and idle it till it get good and hot and find the oil leak. Keep an eye on the cam chain tensioner also and the long cylinder studs that run it between the gaps in the cylinders.
Were your carbs cleaned and all o-rings replaced?
Do you smoke at all when cold with full choke? This is a sign of bad valve guides or valve stem seals but it could also be rings. If you really goose it does it blow smoke?
Sounds like you need to get to know your bike and figure out what's wrong with it cause this thread is all over the place with it's advice. Not the fault of the posters but the lack of being there to see and hear the bike in person.

Agreed, Chef. I am all over the place. I'm getting a great education on this bike and troubleshooting in general. Learning how to divide up the problems and be methodical seems to be 2/3 of the process!

I'm all good on finding and fixing the oil leak - went through the process a few months back when my valve cover gasket let go (in a hard-to-see spot) and then I also rebuilt the cam chain tensioner and replaced the tach gear seal. So yeah, I'll clean things up and find that leak. I'll create a separate thread I get stuck.

Meanwhile, I'll put this thread on hiatus till I get it sorted and have a chance to foul a new plug - hopefully later in the week if I luck out with the oil leak. Hopefully that'll happen - the Missus needs the van tomorrow. :-D

As for your questions - No, I have not rebuilt the carbs yet, but I have the o-rings. And yes, it smokes from the left-hand pipe when I start it up with choke, but I haven't goosed it. Compression from 1 to 4 was a little over 130-120-120-120. Oh, and the valve cover bolts were good - I checked 'em when I had the tank off to inspect the carb slide springs.

[Roostabunny]

Press on, you shall succeed if you dont let IT beat you. :-D

I am resolute. It's time and money, bro. And as poor as I am, I'll run out of the first before the second. Thanks! :-D

[Calvin Blackmore]

not to ba a PITA but have you assured that you plug cap and wire are OK

I dont recall seing that in this thread

but then its a long thread