[zn700a1ltd]

I will make a long story short.
I enjoyed motorcycles since very young.
I have had many bikes, including two of the fastest (and dangerous) ever produced. One was a Suzuki GT750 (Yes! the 3 cylinder, 2 stroke, water cooled) darn fast, but slow to stop, and with wire wheels that make it look "old", not classic. The other was a Yamaha RD350 (again, 2 stroke, water cooled, but twin cylinders) this one had "variable" something in the intake that made it REALLY FAST!. But...in 1992 I was involved in a very bad accident, in a whole different bike, that took me over 2 years to recover. That was time to say good-bye to motorcycles forever........until recently.
There was this guy, that owes me money from some time now, that had a '84 ZN700, and not willing to pay.Being aware of my accident, he keep telling me that he was going to sell the bike to get the money he owes or else I can take the bike to break even, if I wish to.I finally decided to redeem myself and took the bike, to kill any ghosts from the past.
The problem that i have is that the thing was parked for about 3 years!. In a couple of days, i managed to take the 4 carbs apart, clean them, and get the engine running (sort of).
It takes a while to start, then, while running, it leaves a huge cloud of smoke behind, idles very rough and erratic.
I then talked to the guy who used to be my bike mechanic, and after he recovered from the initial shock of realizing that "i was back" he told me that the bike was fine the last time he made a tune up on it (3~4 years ago) and that the problem might be that the rings are "stuck" beacuse of the long time the engine wasnt run and the only solution will be taking the engine apart to fix it or find out what is wrong. Is that possible? I used to trust this mechanic, but I don't know if things have changed. Another guy, a younger mechanic, told me to pour enough "Liquid Wrench" in to the clyinders, let it sit for a couple of days, ant then try again, to see if the rings were "un-stuck" now.Also, I looked everywhere and it seems there are no parts for such bike.
I wish to fix the bike because I was told that it was a limited edition.
ANY HELP OR ADVISE WILL BE MUCH APPRECIATED.

 

[QKENUF4U]

sorry to hear about the accident (been there, dont that, have the t-shirt from the rehab i was in) glad to hear your back. just take your time and have fun.

go get some "RING-FREE" from the local bike shop (if they have it) ive heard nothing but good about it.

did you change the oil,check the tires for dry rot,put new plugs in it,make sure you cleaned the IDLE jets good enough,check the fork seals,check the brake pads,check the tank for rust etc.. :?:

you may have to tear into it but that should be your last resort.

good luck

 

[zn700a1ltd]

Don't know what happened to my previous reply! I have an update.
I installed Champion N21 plugs, that, as I was told, WON"T FOUL!!
The gas tank was cleaned by a process involving hot water and vapor.
New oil and filter was installed, new gas filter also.
My big problem now is, since this is a personal challenge, I wan't to fix this thing MYSELF, but I'm not familiar with the KEI HIN SU carbs.
I cleaned them, twice, but the rough idle it's still there.Which are the IDLE jets? I noticed two jets on each carb, at the very bottom of the "reservoir?", already removed them and sprayed with "carb cleaner".
I followed the advise of the younger mechanic and poured "liquid wrench" into the cylinders. By tomorrow I will know if it worked or not.
What about the "ring free" you mention? does it have a specific comercial name or brand I can look for?
Another fellow suggested to pour a can of an additive called "Jectrol" onto a full tank, to help remove any remaning gum or varnish in the passages.

 

[QKENUF4U]

1. I installed Champion N21 plugs, that, as I was told, WON"T FOUL!!

2. The gas tank was cleaned by a process involving hot water and vapor.


3. New oil and filter was installed, new gas filter also.

4. My big problem now is, since this is a personal challenge, I wan't to fix this thing MYSELF, but I'm not familiar with the KEI HIN SU carbs.
I cleaned them, twice, but the rough idle it's still there.Which are the IDLE jets? I noticed two jets on each carb, at the very bottom of the "reservoir?", already removed them and sprayed with "carb cleaner".

5. I followed the advise of the younger mechanic and poured "liquid wrench" into the cylinders. By tomorrow I will know if it worked or not.

6. What about the "ring free" you mention? does it have a specific comercial name or brand I can look for?

7. Another fellow suggested to pour a can of an additive called "Jectrol" onto a full tank, to help remove any remaning gum or varnish in the passages.

1. CHAMPIONS are the biggest pieces of crap plugs i have ever seen IMHO i only use NGK's

2.never heard of that process. as long as the tank is clean then your good to go.

3. good your covered there, but ya may have to change it again since your adding all this crap to the cylinders and its prob. contaminating the oil

4. you have a MAIN JET which will be the bigger/lowest/exposed jet in the fuel bowl and a IDLE JET which will be small and down inside the passage/carb body in the fuel bowl. they need more than just carb cleaner SPRYED thru them. you need to find some wire that is the SAME inside diameter as the orfice in the jet and run the jet up and down the wire to help clear any gummed up fuel/dirt. air will also do a better job. you can go look on www.ronayers.com at the microfiche for other bikes carbs and see what is inside the carbs.

5. good luck on it running right after the liquid wrench. it MAY help a bit but its not the best solution

6. "RING FREE" is the name of it. its a yamaha product. heres a link
http://websearch.cs.com/cs/search?q...Page=CSNextPrev&invocationType=next&ampTest=1

7. there are lots of fuel additives. TECHRON is one of the best. i like LUCAS myself.

good luck :wink:

 

[zn700a1ltd]

Thanks for your help, QKENUF4U.
I checked a local Yamaha dealer and the do have the stuff.I'm buying it tomorrow.As for the no-foul plugs, do you happen to have the number for NGK or BOSCH, maybe? I installed the Champions for the sole reason they won't foul, but I like BOSCH Platinum 4 electrodes.I have them installed in all my cars and really work great!
I will dismantle the carbs again to check for the diameter of the wire needed to clen them.
PS: A neighbor that saw(actually heard) the Kawasaki running after just a couple of days, came by and gave me a 1980 Yamaha SA50 (Passola) that he had sitting in his garage since forever(at least 5 years!) and from which my now 12 year old was drooling from some time. That means that I have 2 pieces of junk now, but we managed to make the little Yamaha run.It has some problems related with a some vacuum-gas lines and hoses that come from a valve in the cilinder and underneath the gas tank,but the guy says he has those parts brand new somewhere.More on this later..........

 

[QKENUF4U]

Thanks for your help, QKENUF4U.
1. I checked a local Yamaha dealer and the do have the stuff.I'm buying it tomorrow.

2. As for the no-foul plugs, do you happen to have the number for NGK or BOSCH, maybe? I installed the Champions for the sole reason they won't foul, but I like BOSCH Platinum 4 electrodes.I have them installed in all my cars and really work great!

3. I will dismantle the carbs again to check for the diameter of the wire needed to clen them.

4. It has some problems related with a some vacuum-gas lines and hoses that come from a valve in the cilinder and underneath the gas tank,but the guy says he has those parts brand new somewhere.More on this later..........

1.sounds good

2. i dont believe in NO-FOUL plugs or the multiple electrode plugs. from what ive been told/seen its all just advertising hype. you can more than likely get your NGK plugs from any car parts store,they should have a book and be able to order them for you. it may take a few days but i think they are much better plugs and wont cost you your kids college fund.

3. if you can check for this tool at your local welding supply shop or buy one from here.its the tool at the bottom of the page. i have one and love it.
http://www.klsupply.com/HandTools/ht-Carburetor-overhaul.asp

4. hope he can find the parts for ya. if you need hose you can use automotive hose without a problem as long as the I.D. is the same.
good luck
later
lance :wink:

 

[1Adam12]

I second the NGK plugs.... in a consesus of Gpz900r riders thats pretty much all they use!

 

[Stuart]

yup, NGK plugs are the only way to go and the ring-free is a very good product. Check your local instrumental music store (i know that sounds weird) but a place that sells flutes and trumpets and stuff, they have brushes for valves that can get incredibly small for things like piccolos and they are great for carbs.

I quite using little pipe cleaners because it seemed like a piece could break off at any moment and just be a pain & the instrument cleaners have handles.

 

[zn700a1ltd]

Update:
Thanks Stuart for the tip, I already found a similar solution.
My sister plays the guitar, so she breaks strings all the time. I used one to clean the jets!!. They are strong, yet flexible, and will break only by excess tension, not bending. :idea:

Tha Yamaha dealer run out of Ring Free, will be coming in a couple of weeks. :roll:
Tried the Liquid Wrech solution, somewhat worked (less white smoke now). Bike is still hard to start, but the idle is quite smooth now, the sudden, self-acceleration problem still persists.A friend who saw the phenomenon said that carburetors might now need "balancing", involving a mercury-driven apparatus.That "balancing" sounds like Pro's territory, so I'm taking it to a well reputed bike shop for that.
Not trying to start a argument here, BUT, with the amount of oil passing thru the rings, the NGK's plugs DO FOUL in a matter of minutes, and Champions N21 DON'T, probably because they have a recesed electrode, and the fact that they are made for such purpose. :wink:
PS:I got the new parts for the little Yamaha!.Will install them while the Kawa is on the shop.

 

[1Adam12]

Synching your carbs is real easy to do on the wrench list of easy to hard. You just need the right tool to complete the job. My suggestion is that you buy yourself the manometer as it will pay for itself and if you can take the carbs apart you can synch the carbs!

See pics.

http://www.carbtune.com/carboprn.html

 

[vaporgas2000]

1. I installed Champion N21 plugs, that, as I was told, WON"T FOUL


MORE like sure to foul :lol:

good luck and welcome to the forum

 

[zn700a1ltd]

Boy, it was a looooooooooong weekend.
Carbs were taken out and cleaned again.Borrowed the manomenters to get the carbs sync'ed.
Carbs and ALL related stuff (intake box, cable, tubes, tank, seat, etc) back in place.
Hooked up the manometers, then, SURPRISE!, the adjustment screws are SEALED, they were never tampered with before.
Had to return the manometers by sunday morning, so saturday was too short to continue working (had a party to attend with wife, and takes a while to get rid of the combined smell of gas-oil smoke-GoJo hand cleaner).
On sunday, everything was taken apart to figure how to get access to the adjusment screws which i was told are in the back of the carbs, facing to the back of the bike.Will borrow the manometers again one of those nights.I do managed to attach a picture of the monster. Enjoy it!

 

[QKENUF4U]

the synch screws shouldnt be sealed with anything. they are between the carb bodies. the only sealed screw on the carbs should be the AIR/FUEL screws.

 

[1Adam12]

Should be the screw that is in front of the red tape tube in the pic. Your may look different as these are Keihn CV carbs.

Also it is truly not in front, but is an optical illusion. They should be
between the carbs 1/2, 2/3 and 3/4