Power loss

[BA80]

I don't have any smaller jets for the late carbs, early one either for that matter. Stock or larger is all I have.

[BA80]

Try lowering your fuel levels 1/2 mm.

[stereomind]

Already have. I'm afraid if I go any lower, it'll starve at WOT. Even filed down the plastic needle bushings (since I don't have the fancy clip-style needles like the cool kids)

Try lowering your fuel levels 1/2 mm.

[motoman]

For what it's worth, my Venturer is still running rich. I get about 32mpg if I don't get too crazy with the throttle, but I can tell I'm burning way more fuel than I need to. I mic'd the emulsion tubes and needles.. Running stock jet sizes. I might have to hit you up for some smaller jets too! lol

Your actually gonna HAVE to 'hose' each carb while idling to see actual fuel level, which IS required by the manual for 81 and XJ's. Actually, the float setting(23mm) is a 'ballpark' setting as per the manual. NO mikuni carb bank will have the same fuel level just by setting the floats all the same. THAT is why they HAVE to be individually 'hosed' while idling and warmed up.

[stereomind]

Yup made myself a tool out of some clear line just for that purpose.

Your actually gonna HAVE to 'hose' each carb while idling to see actual fuel level, which IS required by the manual for 81 and XJ's. Actually, the float setting(23mm) is a 'ballpark' setting as per the manual. NO mikuni carb bank will have the same fuel level just by setting the floats all the same. THAT is why they HAVE to be individually 'hosed' while idling and warmed up.

[CaptonZap]

Ok CZ, get this right. My engine is a 2H7 021137 (79 F) , the engine the cams came out of is a 2H7 001904 (78 E). If you look them both up in the parts fiche you'll notice that they BOTH take EXACTLY THE SAME cams.

The cams in my engine were fine when I put it in. This ISN'T my first time under the valve cover.

Instead of feeble attempts to insult my intelligence how about a valid attempt to solve the question?

Calm down Greg, I wasn't trying to insult your intelligence, I was trying to point out that you just might be looking for the answer in the wrong spot. In my experience, the first place to look for an answer is the last part you changed before the problem showed up.
I assume that you know what cams that are worn look like, profile wise, and without putting a degree wheel on them, you don't know if they are in spec or not, so that is still an unknown.
I also assume that you know that any manufacturing process can have a bad part or two out of a production run, and they can slip by the inspectors, and the same part number is stamped on all of them.
But I'll shut up, and sit up here in the peanut gallery, and see what transpires.

CZ

[BA80]

Come on Greg, you are smarter than that. The one thing (if I read this right) that you changed was the cams, and you think something else is causing the problem.
In my book, I would go back and take a good look at the cams. Part numbers, wear patterns on lobes, lobe profile compared to take out cam, cam timing, etc.
Or, keep messing with the carbs.

CZ

Sorry if I'm wrong CZ correct me but in my book, and probably yours, this is a blatant attempt at insulting anyone's intelligence.

I've changed WAY more than the cams and it still makes no sense to me and I've been an automotive tech for nearly 40 years.

Brant keeps railing me on voltages at the coils. The FIRST thing I checked and they are as they should be but I still can't get him off that either.

Now, I'm finding that the engine want's LESS fuel than it's needed for the last 4+ years to run right. If you can explain that I'm all ears.

I'm not angry with you but don't speak to me like I'm an idiot that would make a rookie mistake like putting the wrong cams in an engine.

I've said it before and I'll say it again. This ain't my first rodeo. If I come on here with a problem, it's a freakin' problem.

[motoman]

Sorry if I'm wrong CZ correct me but in my book, and probably yours, this is a blatant attempt at insulting anyone's intelligence.

I've changed WAY more than the cams and it still makes no sense to me and I've been an automotive tech for nearly 40 years.

Brant keeps railing me on voltages at the coils. The FIRST thing I checked and they are as they should be but I still can't get him off that either.

Now, I'm finding that the engine want's LESS fuel than it's needed for the last 4+ years to run right. If you can explain that I'm all ears.

I'm not angry with you but don't speak to me like I'm an idiot that would make a rookie mistake like putting the wrong cams in an engine.

I've said it before and I'll say it again. This ain't my first rodeo. If I come on here with a problem, it's a freakin' problem.

+1!.............he's got the problem sorted now...........I think. Taint rocket science, just basic mechanical knowledge when it comes to motor,ignitions,ect.

[ernie elmore]

I have a 80 XS1100G that was running rough, rebuilt carbs, could not sycn #4 carb, vac to low on sync column. Kept getting lower. Pulled head, everything fairly clean for 90K mi. Checked Carb boot screws, #4 carb boot screws loose.
Put it all together, synced carbs okay, ran good.

I bring this up because you said you replaced carb boots. Could a boot be loose or cocked, or something under the boot flange.
Have you sprayed WD40 at the carb boots under part throttle in neutral to see if rpm increases?

[BA80]

Thanks ernie. Yes, actually all the boots are new and tight. It syncs just fine and idles good.

This is a deeper, off idle running problem. I'm working on it

[IanDMacDonald]

So, what's the deal Greg? I've just now read all ten pages after taking a hiatus from the thread.

Only one person on the whole thread mentioned the exhaust, and that was Skids. You said it was new, end of discussion. Me? I'd put the airbox back on, throw your good carbs on, and swap the exhaust and see what happens. That stumble could be electrical or fuel, who knows?

But . . . When u swapped the coils, did you use the harness connections, or did you do a coil relay mod?

[IanDMacDonald]

It never was really a "gas hog" Vlad, except maybe these last couple of trips.

Right now I'm running 1 size smaller pilots and 1 step leaner on the needles than I have been running for the last few years.

What is your main & pilot jet sizes?

[BA80]

I used the same connections that have ALWAYS been there and I've listed jet sizes repeatedly in this thread Ian.

I don't have a stock exhaust, this Mac has ALWAYS been on there since I got the bike.

The entire point that EVERYONE seems to be missing is that this engine has run great for years and just this last few months it's been getting worse and worse and now it's running better on less fuel than it needed before. I can find no mechanical issues.

With the Mac exhaust and pod filters it SHOULD need at least one size up mains 140 (where it's been for years) but now even stock 137.5 jets are too rich for it to run right.

I'm not doing any mods to things that work fine, especially until I get this issue figured out.

[IanDMacDonald]

I used the same connections that have ALWAYS been there and I've listed jet sizes repeatedly in this thread Ian.

I don't have a stock exhaust, this Mac has ALWAYS been on there since I got the bike.

The entire point that EVERYONE seems to be missing is that this engine has run great for years and just this last few months it's been getting worse and worse and now it's running better on less fuel than it needed before. I can find no mechanical issues.

With the Mac exhaust and pod filters it SHOULD need at least one size up mains 140 (where it's been for years) but now even stock 137.5 jets are too rich for it to run right.

I'm not doing any mods to things that work fine, especially until I get this issue figured out.

I agree with you Greg. 140 should be where your main jet should be. But, your signature shows 45 for your pilots. Have you gone back down to the 42.5's?

[BA80]

I have now. The set of carbs I have on right now are 42.5 pilots, 140 mains and one notch lean on the jet needles.

As of this morning when it stops raining I'll be back to 42.5 pilots, 137.5 mains and one notch lean on the jet needles.

I'll se how that runs.