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Discussion Starter · #1 ·
I have read the posts on the carb problem/solutions. I have a very similar as Jason0. The bike wants to idle up and down when at operating temp (with choke open). It also idles down slowly after reving; when it doesn't alittle clutch usually brings it down, but then idles too low. When idling below 2K it wants to skip. One side of the air filter box has to be taped off or it will bog down when giving gas. Runs great on the road, plugs correct color, carb holders do not leak. Should I remove and clean carbs again. I am concerned with the miss it has below 2K.... terrible engine noise when this happens.
 

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Discussion Starter · #2 ·
83-440

After further research and repairs I have fixed everything in my previous post. Solution was .......syncronizing the carbs. Made a sync tool with a yardstick, plastic tubing, zip ties, and bar oil for chain saw.....cost $6.

Now a new issue, the bike seems to top out at 65MPH as far as power, seems like at 65 it should be able to drop a gear and go another 15-20 MPH easy. Runs great otherwise. Anyone have a helping answer?
 

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We need to know what type of bike you have in the first place, if it's a 20 year old 250cc bike then that might be it's top speed :) If it's an 04 zx9r then you may have a problem
 

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It's possible that gearing has been changed to increase acceleration so much that the bike's topped out at 65. Do you have a tachometer? Is your engine redlined? Do you ever feel the clutch slip?
 

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Discussion Starter · #5 ·
83-440

Stuart- it is a 1983 KZ440LTD

Bob- It is stock (so I was told), the tach reads 6K at 65, or there abouts, in sixth gear..plenty of RPM before redline. No clutch slip. I have plenty of throttle left, but very slow acceleration when I roll it. There is no bog, but no power either. I was thinking maybe the main jet may need cleaning? I read somewhere fouled main jet will cause problems at higher RPMs?
Thanks
 

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Check the main jets for obstruction. Also check the float level in the carbs. Check your advance on the ignition timing. Does the bike pull hard to redline in lower gears?
 

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Discussion Starter · #7 ·
Pull decreases at upper end of RPM as gear increases. I have found some info on working range of carbs pasted in italic:

( If the engine is having troubles at low rpm (idle to 1/4 throttle), the pilot system or slide valve is the likely problem. If the engine has problems between 1/4 and 3/4 throttle, the jet needle and needle jet (most likely the jet needle) is likely the problem. If the engine is running poorly at 3/4 to full throttle, the main jet is the likely problem. )

Can anyone tell me what the top speed should be for the KZ440? I have searched the net, but found nothing specific on speeds/RPMs through gears.[/img]
 

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I started riding on a Yamaha Exciter 250 and it would pull to 80-85 with my 240lbs. aboard. I would presume somewhere between 80 & 100 for the 440. (edit) You can figure top speed by using ratio's and the speed/rpm you already have. example = If your bike accelerates 10mph in high gear for a 1000rpm increase in engine speed and you have 3000rpm the bike won't turn in engine speed then you have 30mph it won't make. This is a theorhetical top speed and can be limited by aerodynamics or engine output. (edit)
 

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Discussion Starter · #9 ·
After more adjustments (found specs on net for idle screw which should be 2 & 3/4 turns out) it seems to be a little better, but haven't checked plugs. Fifth gear, 75MPH at 7500 RPM was still picking up speed...slowly; went to sixth gear...acted more like over-drive.....same speed, less RPMs, no balls.
I did find two site that mention speeds. One said max performance was 70-75 MPH for this old bike, another was the specs as new.....75-80 easy with charts that go to 95 at 9500RPMs, which is redline (this was the 5-speed 70s model).

Bob- What you are saying then is I should have 20 MPH more to get out of it at 7500 RPMs since I have 2K RPM left? I suppose I'll take the carbs apart again to check main jets, but not til the first week of August.
 

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I have an 81 kz440 ltd and It will do 80 like a dream. I wont of course because I am just learning to ride, but I got it there pretty easy once.
 

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Hi. I know this is an old thread but does anyone know what the top speed of the KZ440 ltd - 1981 is? mine max out at 80, way below the redline. What can be done to make this puppy go faster. I was hoping to cruise all day at 80, with a max near 100mph.
 

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The problem of the unsteady idle is most likely an air leak in the pilot circuit where the bike operates at idle. I suggest you remove the mixture screws and install new orings. I can't recall for sure on your bike but it seems there are o-rings under the mixture screws along with metal washers. If these are deteriorated, the bike's idle will hunt around due to air leaking into the air/fuel mix at this point.
 
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