Is there a good, easy to follow site somewhere on line for DIY carb rebuilds? I'm going through the '77 KZ400 for Mrs.Mini, and thought I should probably do a rebuild and re-jet. The P.O. installed a pair of megaphones (which are nice) but didn't re-jet the carbs, and I'm noticing a flat spot when accelerating. I found a guy that will rebuild, re-jet, and polish them(looks awesome!), but $200 is half of what I've got into the bike.
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Jan. 16, 2011 8:35 a.m. minimac SuperDork
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Jan. 16, 2011 8:39 a.m. 914Driver SuperDork
Is the stock airbox still there? Every bike that I put K&Ns on had a similar flat spot.
Are you sure they need rebuilding? What if a rebuild doesn't change anything?
Dan
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Jan. 16, 2011 6:46 p.m. 44Dwarf Dork
Well 77 was mixed year for carbs. How tall are the domes on the top some are thin sheet metal (zinc or chrome plated) some are cast alum about an inch and a half tall. Both are consant velocity type carbs this makes them dificalt to tune but not imposable. Were is your flat spot? How does if feel slight or hard come on? hows it end? What rpm is it at.
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Jan. 17, 2011 7:48 a.m. minimac SuperDork
The bike is totally stock, including airbox, with the exception of the megaphones. the domeson the carbs are short and chromed. The bike will pull strong from idle up to around 4500 and just won't pull anymore. Standing still, it will rev as high as I want, but when riding, it just won't pull any higher. It doesn't break up. I also need to adjust the valves and check ignition. Is there a way to check the coil(s)? The bike sat for a year before I got it, Mrs.Mini rode it for a season, then parked it(2 years)for her scooter. This year she wants to ride the bike again. I didn't ride it before so I don't know if it was like this before or just since we got it. When it was put up by us, it was done properly.
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Jan. 17, 2011 7:55 a.m. ClemSparks SuperDork
Watching this thread with interest as I expect to receive an '80 Kawasaki 550 LTD this weenend in trade.
Clem
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Jan. 17, 2011 8:16 a.m. 1988RedT2 HalfDork
My '76 has the taller domes on the carbs with the vacuum pistons. I believe '77 saw the conversion to a vacuum diaphragm, and the rubber diaphragms are known to fail with age. I would pull the carbs apart, check the diaphragms, and clean eveything thoroughly and see if that fixes the problem. The Kawasaki manual has some very good info in it, and is widely available for download.
The Kawasaki Twin Owners Forum is an excellent resource: http://www.armbell.com/kz400/index.php?mforum=kz400
If you find a good source for carb parts let me know please! I've had trouble, to say the least! Mine seem to need attention frequently, though my problem is a rough idle. The high speed operation is fine.
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Jan. 17, 2011 8:31 p.m. 44Dwarf Dork
yup short chromed ones have rubber diaphams. They do swell and get gummy. I'd start there along with good cleaning and blast with rubber tiped air gun and 80psi or more.
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Jan. 17, 2011 8:38 p.m. minimac SuperDork
In my surfin' for solutions, I found that Honda CB500T carbs will fit (both ends). They are supposedly more plentiful, cheaper, easier to find, and easier to rebuild. I'll see. Thanks guys for the input!
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Jan. 17, 2011 9:21 p.m. BoxheadTim SuperDork
A friend of mine restored a CB500T and had endless problems with the carbs. His experience would suggest that the Kawa carbs are either utter junk or someone was looking for the wrong sort of solution to a problem...
I'd check the carb diaphragms, if they're torn then new ones are in order. While the carb's apart, see if you can get it ultrasonically cleaned.
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Jan. 18, 2011 6:53 a.m. 44Dwarf Dork
It's been my experience that since about 1990 if anyone sprayed carb cleaner in to the carbs while running or not the diaphragm's will have lost there usefulness. Something in carb cleaners changed then and what ever they took out and replaced it with don't like the rubber. If you look in to the throat of the carb on the top of the air cleaner side you'll see a banana shaped port this is the atmosphere side of the diaphragm. Theres another port under the rubber on the oposite side of the throttle plates make sure the "JET" is clean.
Finding tuning parts is difficult the guys in the know want to sell "kits" = $$
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Jan. 18, 2011 11:53 a.m. Rusnak_322 Reader
What place is going to rebuild and polish them for $200? I can spend $200 just on the diaphrams and another $65 for rebuild kits for my Honda 360.
Thread Jack - I want to get the carbs cleaned up - the parts cleaner made them clean, but didn't make them look nice. I am looking for a place to have them blasted or ??
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Jan. 18, 2011 6:04 p.m. 44Dwarf Dork
Go to bakeing supply comapany get 50lbs bag of baking soda. load up the sand blaster with baking soda. Blast and toss in hot water.
