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i recently came across a 86 zx 900 ninja. i know that it runs but i want to check a few things before i spend a lot of money. i need to know how much compression this bike should have. i am also curious to know how many psi the fuel pump should be putting out. i have tried calling the dealers but it is kinda hard to find anything out on with it being so old. if anyone could help me out i would greatly apreciate it.
 

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Hey there.

I've got an 85 ZX900A2...that is a GPZ900R, same as yours.

First, they don't have fuel pumps as stock bikes.

Second, the compression ratio is 10:1 according to my shop manual. If you run a compression test, the gauge should pump up to about 175-185 psi, with no more than a 10% difference between the highest and lowest reading for all 4 cylinders.

Hope this helps some. If you have more questions, let me know...they're great bikes. :D

ZX
 

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My ZX900 A3 ('86)

Hey guys,

Always nice to see words from a fellow ZX900 owner! I own an '86 ZX900 A3 that runs GREAT. However, I must warn you of overheating problems. After I ride for over 40 mins. my bike begins to get quite hot. Everyone i've talked to had the same problem and I've heard the problem was even worse in '85. There was so many complaints about this, that there actually was a recall as well. Also, take a listen to cam lobes as they have tendency to go soft and required replacement on these bikes. Once again, a problem more common in '85. The compression ratio on the 86 according to my haynes manual is 11.0:1 so I dunno about that 10:1 the other guy was talking about. He could be right though, certainly if he's referencing the true kawasaki shop manual. So, soft cams and overheating. Watch for it! And hey guy with the '85, have you experienced overheating difficulties and if so, what have you done about it? As ZX Kawboy said.....they're great bikes :) ur gonna love it!
 

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Oh yeah, the overheating was horrendous!

I had a bad thermostat sensor that kicked the fan on *too late* to help. So, instead of paying $110 for a new one, I simply re-routed the line to a manual switch instead. Along with replacing a hideously clogged radiator, that solved the problem in no time. (The fella I bought it from had no concept of preventive maintenance)

My cam lobes are in good shape (been watching out for it) and you're right..I double checked my book for the compression ratio...11.0:1 is dead on. I checked my bike, too...and BINGO...11.0:1! :D

These things are big, heavy, and *fast*....just the way I love'em!

also..check out this site...

www.gpz900r.org

It's a good place to find other lovers of the Big Nine

Later

ZX
 

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Overheating Questions

That's incredible! Did you just have your radiator flushed or what? If that's all I need to do that would great! My fan turns on a little before the halfway mark on the temp gauge, so I think that's ok. From what I understand, the fan is actuated through an oil temp sensor and if that fails, a coolant temperature sensor pix up the duty of grounding the fan(turning it on) 10 degrees later. Anyway, I don't think either of those sensors are at fault as I said because the fan comes on fairly early. That's interesting that you mention your radiator was clogged because I replaced my thermostat and my water pump and when I removed the old water pump- there was scale EVERYWHERE inside. Like a heart so full of blockage it was about to have a heart attack! Neway, I'm starting to think that perhaps this same scale build-up is present in my radiator jus as you mentioned clearing it up solved the problem. Also, I'm wondering what type of coolant/water mixture you are running. Did you ever try purple ice or any of those racing super coolants? What is your opinion on that?
 

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site

that's a great site! thanks. big fast and heavy is the way i like it too! that's why despite the problems- it's still such a great bike and i'm still so glad i bought it. :p
 

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I had to replace my radiator. The old one was so caked with crud inside, it was beyond saving (after 4 flushes, and a few trips with CLR!!)

I found one at a local yard, so I was in good shape.. :D

Now, if I can get those damned carbs worked out, I'll be in great shape.

ZX
 

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u use a 50/50 standard water/ethylene glycol mixture? caky eh? hmmm... that could be my problem. i'm gonna try the super coolant and see what happens.
 

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i'm gonna go with Zerex, made by valvoline. I've heard watter wetter smells like **** and zerex is supposedly just as effective without the smell. I read a test comparing purple ice to zerex and water wetter and zerex came out on top. According to the test data, all three cooled equally well, but water wetter had the bad smell and purple ice promoted corrosion instead of helping to reduce it as the bottle claims. So, i'm going with zerex. I ordered it already and i'll try it when i get it. When you use water wetter, what kinda mixture do you use? I'm thinking to start off with a 20% coolant/80% distilled water mix with a shot or two(or whatever ratio is suggested per oz.) of zerex.
 

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NO OVERHEATING! THE STORY OF A WATER WETTER MIRACLE!

I just put water wetter in my zx900 in a 4% water wetter, 16% coolant/antifreeze, and 80% distilled water mixture and my TEMPS ARE WAY DOWN!! this product is [email protected]#$ING AWESOME!!! Too anyone who's been overheating, USE WATER WETTER! IT WORX!

The happiest ZX900 owner EVER!
-dimitris
 

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i have a 86zx900 that constintly overheats on me. come to find out i was also leaking coolant from what looks like a freeze pulg ont the left side of bike behind the alt.cover on the block.has anyone else seen this hole. ill try to get a pic of it this week.thanks for help guys youve been great
 

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This is my fifth season with my 84 Ninja 900.
I have been over the bike many times and have gotten to know this rig quite well.

The coolant pipes ( the bike has two, one behind the headers and the other above the carbs ) will occasionally leak a bit of coolant. If yours leak all the time then you will need to pull them off and replace all 4 o-rings that seal them to the block. This is a heck of a job as the fit is very tight. If you decide to do this repair you will need to pull the carbs as well. Make sure you get the exact same size o-rings for the pipe or you will be a 'cussing. When I did mine last year I used a bit of white grease to assist them while reinserting the coolant tube. If you choose to do both at the same time set aside 3/4 of a day. At the same time you may wish to flush the cooling system. I flushed mine last season and the difference was noticable right away. I used pre-mixed coolant from Honda and it works well. I also have a manual fan switch as the previous owner gave up trying to fix the original bits.

A few areas of concern on that bike BTW,

Fueltap, a must to rebuild.
Sidestand switch, make sure its clean and not interupting things.

A good site for only that bike:

http://www.gpz900r.co.uk/

MAke note of the parts section and the troubleshooting guide contained within one of the sites listed.
 

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KawiMan900 said:
i'm gonna go with Zerex, made by valvoline. I've heard watter wetter smells like **** and zerex is supposedly just as effective without the smell. I read a test comparing purple ice to zerex and water wetter and zerex came out on top. According to the test data, all three cooled equally well, but water wetter had the bad smell and purple ice promoted corrosion instead of helping to reduce it as the bottle claims. So, i'm going with zerex. I ordered it already and i'll try it when i get it. When you use water wetter, what kinda mixture do you use? I'm thinking to start off with a 20% coolant/80% distilled water mix with a shot or two(or whatever ratio is suggested per oz.) of zerex.
Tell me more about this Zerex stuff. I looked at Valvoline's website and don't see anything except the original green antifreeze/coolant. Sounds like what you are talking about is a WaterWetter type product? Do you have a link to this product or the review you mentioned?

I'm working to get my '85 cooled down and want to try all these tricks. I'm ordering an aluminum fan from Muzzy http://www.muzzys.com/fans.cfm and want to go through the whole cooling system when I put it on.

As far as the recall for the cooling problem. I was always told it was just some sort of resistor deal to make the guage read lower?

I did check my plugs over the weekend and found a lean hole. I got help adjusting the pilot screws, which were leaned out to pass emissions and got a good carb sync done which seems to have lowered the temps some but I need to do more. She is much smoother and purrs like a kitten (tiger) now. Carbs needed sync'd badly.

Thanks!

...Diane
 

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Ericthejet said:
Cleaning my cooling system with a flush worked mint.
I run premixed Honda coolant, temps down about 10%.
Did you use a regular radiator flush chemical like Prestone and did you go through the whole procedure according to the directions? I've done this in my car a bunch of times but have the little garden hose fitting deal that goes in a heater hose that facilitates getting all the flushing stuff out. How many times did you fill and drain your cooling system to get it all out?

Any thoughts of just running the radiator to a radiator shop or would they murder it?

...Diane
 

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I used the aluminum safe flush that Prestone makes. You mix it with water and I had a pail full so I flush it thru the bike 3 times.
I then ran water thru, opened all the bleeder screws and did a final flush allowing the bike to come up to temp. just a bit.
You can do the rad at home in a large pan, CLR works great.
I also used a "pick" and repaired some of the bent matrix, did the oil cooler as well. The OCooler was quite dirty externally, rocks etc. I think that helped to keep the temps. down a bit also.
 

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I have an '85 Ninja 900 that runs at the mid point or below of the gauge when at speed. When idling in traffic or going slow the temp. starts to climb. The odd part is that the fans doesn't seem to come on unless I shut off the bike, then the fan starts. If I turn the key to the 'on' position, the fan stops. Turn to 'off' it starts again. I can't tell if the fan is running when going 70 so I don't know if it ever comes on when the bike is running. Any thoughts?
 

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I have an '85 Ninja 900 that runs at or below the mid point of the gauge when at speed. In traffic or going slow the temp starts to climb. The odd part is that the fan doesn't come on until I shut the bike off. If I turn the key to the 'on' position the fan shuts off, key off, the fan comes back on. I can't tell if the fan is coming on or not at 70 mph so I don't know if the fan ever comes on when the bike is running. Thoughts?
 
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