About to sell this &*$#!#% thing

[eastern]

So here it goes. I do not know what to do next. I purchased this bike a couple of years ago with it just sputtering. So I went to town on the carbs, dipped them, and replaced the orings. The charging system was a mess. Replaced the R/R with a used one and it worked great. Used the bike all year long. Then for some reason last fall after a couple hundred mile ride it did the whole shut down like it wasn't getting power at high rpms. Pull over and it would revive itself. Take back off and blam...same thing. So it sat for a while.

Took it out this spring and same thing. Now it hits a wall at 6,000 rpm. So I read through the forums. Either fuel or spark. Bought a new petcock. No change. Ok...went the route of coils. The coils were not right up to spec...but not terribly off. So I purchased some 03 Bandit coils. I then checked and adjusted the valves. All were too tight. New shims from Z1 and everything is in spec now with the valves. Used my new Morgan Carbtune and synced the carbs. So what now? The bike runs great under 6,000 rpms and less than WOT. HMMM...so I thought maybe the main jets were clogged or had debris in them. Took the carbs off and took the float bowls off...something doesn't look right with #1. The main jet had actually come unscrewed and was off in the float bowl. Screwed it back in got excited that this was probably the problem. Put carbs back on and warmed her up. Guess what? Hit a wall at 6,000 rpms with WOT.

I want to blow this thing up.

[TheCafeKid]

I would suggest soaking them again. And what exactly is the &*$#!#% thing we are talking about?? LOL We can get it running bro, dont give up hope yet. There is NOTHING on these old bikes that cant be fixed. They may give you a headache, or an ulcer, but they WILL run right again if you have perserverance.

[8trackmind]

Check the intake boots between the carbs and the airbox.

[Nessism]

Sounds like an ignition problem, although thoses carbs are highly suspect based on that jet coming loose.

Not sure about those Bandit coils, what is the resistance? point systems need 4-5 ohms and early CDI ignition coils are about 3 ohms. Many newer coils are lower than this so check that.

Lastly, if your bike currently has a CDI, hitting the wall at 6000rpm sounds like it could be an ignitior issue. You can get a Dyna S ignition for about $120 which should take care of that problem.

Good luck and don't give up.

[eastern]

I actually replaced the intake boots and orings last year when I did the carbs so they should be good. I read on here though that the bandit or katana coils should be a direct replacement for the factory ignition. Plus I ordered brand new plug caps and all.

When I am refering to blowing this thing up...I mean the bike.

[TheCafeKid]

I actually replaced the intake boots and orings last year when I did the carbs so they should be good. I read on here though that the bandit or katana coils should be a direct replacement for the factory ignition. Plus I ordered brand new plug caps and all.

When I am refering to blowing this thing up...I mean the bike.

Yeah got that much, but WHICH bike??

[8trackmind]

I actually replaced the intake boots and orings last year when I did the carbs so they should be good.

I've been through this with my 550.

Did you replace the ones between the carbs and the airbox? Are they sealed? The two in the center are the hardest. If they are not sealed, the bike will not rev over 5,000. It'll feel just like it's running out of gas. CV's have to have a slight vaccume on the airbox for the slides in the carbs to work properly.

[eastern]

Lol....sorry. It is a 1980 550L.

I never replaced the airbox boots...just the intake boots. Would that really be the problem. They seem to be sealed.

[Dave8338]

Could very easily be the problem, but before you jump out and order them, run some plug chops and hover right around that mystical 6,000RPM number. If indeed things are leaning out...it will show up on the plugs as white or VERY light tan color. If not, fuel is not the issue and we'll need to look elsewhere. It will run, they all do!!! :-D

[8trackmind]

Lol....sorry. It is a 1980 550L.

I never replaced the airbox boots...just the intake boots. Would that really be the problem. They seem to be sealed.

That bike is one of the hardest models to get the carbs in and out of. I'll bet the two inner carbs are not sealed at the bottom. I usually push the carbs as far back toward the airbox as I can. Tighten those clamps, and then slide 'em forward and do the engine side.
And yes, if the airbox boots are leaking, the bike will not pull past a certain RPM.

[Jethro]

Then for some reason last fall after a couple hundred mile ride it did the whole shut down like it wasn't getting power at high rpms. Pull over and it would revive itself. Take back off and blam...same thing.

Honestly, this sounds very, VERY much like the same issue I originally had on my bike. Do you have an inline fuel filter on the bike? Are you sure you have 5/16" fuel line and not 1/4"? Is your tank cap venting properly? Sounds like it's getting choked at WOT.

The other thing I would check is the timing advancer. Make sure the springs are not broken and the advancer is lubricated.

In regards to the carbs, if the trouble is at WOT, I might spend less time thinking of them as the problem. Wide open is the easiest function that carbs perform. It's starting, idle and the slow speed circut that are complex tasks.

Have you performed the charging test and made sure it's charging properly? Have you tried applying a little choke when it hits the wall to see if cutting off air helps? You might also get an idea of if you have a fuel mix problem if you perform a plug chop when it loses power.

[salty_monk]

Also sounds very similar to the ignition problem that I had... but you should also get some "popping" back through the carbs (or at least I did...) Well worth pulling the plugs & checking spark against the head of the engine, on mine I could see number 3 plug had a weak spark that was intermittent.

Dan

[eastern]

Here are some answers to some of these questions.

I do not have an inline fuel filter and it has the original fuel line.

I keep reading about the tank cap getting clogged and not venting properly. How would I check this while riding...I guess riding without the cap? When I feel like it is hitting that wall I pulled the choke and it didn't help at all. Not sure what that means.

Actually the carbs perform great at idle and warming up. It just hits a wall and then starts to lose speed when I have it at 3/4 and WOT around 6,000rpms especially in 6th.

I did a plug chop earlier last week before I found out the main jet was unscrewed and plug #1 was the only one that was black and seemed somewhat sooty and a little bit shiny.

Maybe I need to resync the carbs now that I have screwed the main jet back in #1?

[TheCafeKid]

Off chance idea, but is your clutch performing ok? Do the revs STOP at 6000 or does it just quit grabbing around there?

[Dave8338]

Here are some answers to some of these questions.

I do not have an inline fuel filter and it has the original fuel line.

I keep reading about the tank cap getting clogged and not venting properly. How would I check this while riding...I guess riding without the cap? When I feel like it is hitting that wall I pulled the choke and it didn't help at all. Not sure what that means.

Actually the carbs perform great at idle and warming up. It just hits a wall and then starts to lose speed when I have it at 3/4 and WOT around 6,000rpms especially in 6th.

I did a plug chop earlier last week before I found out the main jet was unscrewed and plug #1 was the only one that was black and seemed somewhat sooty and a little bit shiny.

Maybe I need to resync the carbs now that I have screwed the main jet back in #1?

If you're not seeing any change in the "wall factor" once you've applied the choke...you are running out of fuel. If it were vent cap related it would be more of a distance ratio and not an RPM problem. Yesssssss a resynch would be a good thing but were it up to me, I'de loose the inline filter and retest it.