lack of acceleration

Just an 1982 kz440 Ltd it's almost mint only 10900 miles. But i'm having a problem; The problem I'm having is a lack of acceleration. It runs very smooth but it picks up speed very so and has a tremendous problems climbing passed 5000 RPM's, won't go above 7000 RPM's. The top speed is stopping at about 60mph and wont maintain it climbing up hills.
I' ve cleaned the carbs, check and clean my timing advancer, check coil. It doesn't backfire or cutout during this time, the compression is good. it does make a slight popping when decceleration thru. don't know what to do from this point? The bike came for calf. if it makes a differance. :S:angry:

I had the same problem on my Corolla. Check the compression ratio on each cylinder. It is most likely one of the piston rings, or maybe two. If it is getting bad compression and you can't fix it immidiatly, squirt a bit of oil into the cylinder through the spark plug, it will seal up the piston sidewalls and lubricate a bit before burning up, this should increase your compression, and maybe solve the problem completely.

check the intake manifolds for leaks by spraying them with carb cleaner and see if the idle changes

Missed the part were you checked the compression, scratch what I said.

Intake leak?

Isn't popping during deceleration one sign of exhaust leaking? Maybe check your exhaust manifolds or gaskets.

I shrunk the spark plug gap and readjusted the valves. it seemed to help a little but it still not quite right. also the it seems the more I ride it the better it gets. I don't think that i mention that it's been stored since the winter of 1993.
Need more help!!! Just about to the point that I'm going to have to take it to the shop. It would the first time in 15 years of riding i ever had to take something to the shop.

Please HELP!!!

What altitude is the bike operated? What is the current jetting? Have the bike's intake or exhaust been modified. Just a litttttle bit of information is helpful...

The problem COULD be related to one of these issues or the bike could be starving for fuel. That is, the petcock obstructed, the fuel lines clogged or perhaps the carbs themselves are clogged with goo/sediment, etc. The other possible problem source is that one or both slide diaphragms are holed/torn/ripped. If this is the case, engine vacuum can't lift the slide sufficiently and you will not meter sufficient gas towards higher rpms while at lower, your bike will run adequately.

If you want to fix this problem:
1. provide info requested
2. take steps to remove potential fuel obstructions
3. check slide diaphragms for damage

wow, that sounds like my bike.....did you steal it? lol i have an 82 kz440 that was stored since 93 as well and have the same problem i think??? i always thought it was just a gutless 440 but now that i think about it, even in first gear its pretty lame for acceleration. Mine was opperated down on the coast of BC and now its up a bit higher....would that have anything to do with it??

wiredgeorge wrote:

What altitude is the bike operated? What is the current jetting? Have the bike's intake or exhaust been modified. Just a litttttle bit of information is helpful...

The problem COULD be related to one of these issues or the bike could be starving for fuel. That is, the petcock obstructed, the fuel lines clogged or perhaps the carbs themselves are clogged with goo/sediment, etc. The other possible problem source is that one or both slide diaphragms are holed/torn/ripped. If this is the case, engine vacuum can't lift the slide sufficiently and you will not meter sufficient gas towards higher rpms while at lower, your bike will run adequately.

If you want to fix this problem:
1. provide info requested
2. take steps to remove potential fuel obstructions
3. check slide diaphragms for damage

well, on my bike, the petcock is clean, new fuel line, and the carbs have been cleaned.....still pretty slow.....and as for the torn diaphram, in neutral it revs up just fine, not slow at all....

Pull out the baffles from the exhaust and see if any critters made a home in there while in storage. Too much back pressure from a partially blocked exhaust could do that.

Post edited by: Scotty355, at: 2006/04/20 18:20

While we're speculating...

If one of the valve springs was fully compressed when the bike was put up in '93 and the thing wasn't turned over for 12 years, that valve will be on what is essentially a weak and slightly short spring. It will float in the normal operating RPM range. You're running on 3 cylinders (on a 4cyl bike) once it starts floating. You won't see this when you do a compression check. Some folks can hear it. I'm not one of them

well, as for the exhaust being clogged, mine is straight piped, and definatly arent clogged lol and as fro running on one cylinder, mine is definatly running on both