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85 zl 900 handling issue

willwins May 23, 2015

  1. willwins

    willwins Member

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    I just bought a 85 zl 900. Bike had been sitting a while, but all there. The only mod was k&n pods. Bike fired right up and was able to be ridden.Brought bike to shop had it all checked out,carbs needed work and other basic stuff. Picked up the bike drove it home. haven't ridden a bike in 30 years. This bike is awesome love it. Noticed after riding for a while it seems to be very unstable, almost scary. Not a vibration more like a weave feeling in cornering and at lower speeds doesn't seem to track right. Tires are 7 years old no dry rot. Could it be pressure in shocks or steering bearing.Any help would be great. I am lost.
     
  2. kawboy

    kawboy Supporting Member Technical Author

    7 year old tires are going to be hard and slick.
     
  3. paulfun

    paulfun "King Of The 1/4mi (Internally Stock)"

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    You can use some air in the forks and shocks to help determine exactly where the problem is coming from. Don't overfill them as they are not high pressure, about 18PSI will give a very solid feel taking away any unwanted whooshy feel for testing but I find 12PSI to be about the best average for most of my rideing.

    Your tires being 7 years out with undetermined condition and use- vs-sitting time would be a major concern for me It seems to me that everytime a tire sits without being used regularly even without getting dry rot they give me some type of ill handling so I simply change out old tires and always go threw all the wheel bearings and steering stem bearings on any bike I get. Too many people out there including shops who don't do things right for me to trust any of them.

    What size and brand tires are on the bike can also make a difference in how the bike handles at varied rider usage. I know that for me a taller rear tire that isn't quite right for the rim will give a smooth ride at Harley speeds but at any thought of hard fast back road rides the bike feels very unstable. So making sure you have a good set of matched tires in the right size for the bike can also make a difference depending on your skill set.


    How about posting some pics of your bike for us?
     
  4. Jarney

    Jarney Strip Warrior Staff Member Administrator Super Moderator Supporting Member

    Yeah, give us some more info. That could be a wide variety of things, from wheel bearings, steering head bearings, slightly tweaked forks, tire/rim issues, brake issues, etc. Later.
     
  5. willwins

    willwins Member

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    paulfun,

    Regarding pres in shocks the owners manual says not to check with tire gauge. How do u check the pressure? when I check the owners manual on the forum that somebody was nice enough to scan thank u, max air frt 36psi and 28psi rear. You feel as though 12Psi in each side is adequate. You have to excuse me I do not know very much about this. and I don't want to make a mistake. And also what about the rear. The tires are 1099018 56h metzler me880 marathons and 1708015 77h rear. Tires appearance wise are good no cracking. I believe bike was stored indoors for a while. Just strange how when first riding bike seems ok, then 20mins after riding it starts feeling very sketchy. thanks to all of you for you replys. I posted everything in at once. I will post pictures . thanx
     
  6. rkerg

    rkerg Senior Member

    The thing with adding air to the front & rear shocks is not to use compressed air unless you have an attachment that limits the pressure to a very low number. You can find those things in the spray gun section of a hardware store. The easy solution is a bicycle tire pump. The air capacity is small and can be damaged by overfilling with high pressure.
    Using a compressor you can literally overfill the rear shock in 2 seconds. There is nothing wrong with checking the pressure with a tire gauge.
     
    Last edited: May 24, 2015
  7. willwins

    willwins Member

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    rkerg,

    Thanx. I am going to check the pressure now. I hope that is the problem. thanx again.
     
  8. f1nxlife

    f1nxlife Supporting Member

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    The ZL 900 is not built to handle well going around corners,,,yes you can use a fork brace,,you can put air in the front and rear,,I run 5 lbs in the front and 25 lbs in the rear,,,THE BIKE IS STILL GOING TO WALLOW IN THE CORNERS,,.,you have to learn how to ride this bike around its shortcomings,.,RIde it like a dirt bike,,,take your foot off the inside peg ,,unweighting the suspension ,. when trying to corner fast..your lean angle will increase ,but the pegs are still going to grind,,depending on how aggressive you are...High speed freeway riding,,the bike is still not going to track exactly straight,,,depending on the head wind,,,I love riding my 900....The ZL 1000 is more stable...
     
  9. willwins

    willwins Member

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    rkerg,

    thanx for the info. I also should note when I brought bike back from shop. This was first time riding it. It was fine almost got home,it started feeling wierd. Checked tire preasure when I got home found 23psi frt and about 10 psi in rear. The tires being old could that have created the problem. The rear tire is also a 1708015 instead of 1608015. what do u think. Thanx.
     
  10. paulfun

    paulfun "King Of The 1/4mi (Internally Stock)"

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    You really shouldn't have any problems with the 170/80 tire. Yes using just 18 PSI will give a very good test point and you will find most folks don't run any higher than 15 PSI with many others not running anything more than atmospheric pressure (0) in them. Much of your choice for overall pressure is going to depend on how you ride the bike. Checking pressure with a tire gauge can be tough because with each check you loose 1PSI of pressure. The best is to buy a low pressure gauge and use it but any tire gauge will work as long as you plan for the loss with each check.
     
  11. R. J.

    R. J. Senior Member

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    :hello: I run 25 PSI in my front forks. Tires that are 7 years old should be changed according to the manufacturer. If a bike sits for years without being moved it can develop a flat spot causing handling issues. Mostly front tire/rim wobble.
     
    Last edited: May 25, 2015
  12. willwins

    willwins Member

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    f1nxlife,

    thanx for the info. I guess a bike that's been sitting a while you have to expect things like this. I really just need to check the things all of u have suggested. Thanx so much. I will let you know on progress.
     
    Last edited by a moderator: May 25, 2015
  13. jkrstls

    jkrstls Member

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    @paulfun I just brought home a 86 zl900 with 170 kendas on the rear and felt exactly like what you were talking about. Any tips on what tires I should?
     
  14. DirtyRider

    DirtyRider Member

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    I'm using 10 pounds front and rear right now, rear shocks set at 3. I noticed 0-0 pounds did make lower speed cornering a bit friendlier but highway straight high-speed was wobbly. Now I just take it easy through the twisties and the bike has the extreme acceleration to more than make up for it on the straight. High-speed stability has more use for me than cornering ability anyway, I live out in the boonies, highway is 90% of my trips.
     
  15. DirtyRider

    DirtyRider Member

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    Regarding tires, I think there is maybe 2 brands that still make the 160 this bike came with but they are premium priced. The 170 is adequate and saves a lot of dough. I'm running shinko tourmaster, $110 for the set. You can burn the rear if you want for that price.
     
    R. J. likes this.
  16. rammy1500

    rammy1500 Supporting Member

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    I put shinko's on earlier this year and replaced the fork seals and have a wobble. Iron Pony swears the tire is balanced, but I'll put it up on the lift over the winter and check to see if I can spot anything out of alignment.
     
  17. R. J.

    R. J. Senior Member

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    :hello: Is it the front tire. I have seen more than one new tire that was defective from the factory that causes problems. Have Iron Pony ride the bike. How are your wheel bearings & steering stem bearings.
     
  18. rammy1500

    rammy1500 Supporting Member

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    Bearings are all tight, I'll look at it over the winter and figure it out before heading to Daytona in March.
     
  19. 87kawzl

    87kawzl Senior Member

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    R. J. likes this.
  20. R. J.

    R. J. Senior Member

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    :hello:Rammy when you & your son come to Daytona in March call me when you guys get into FL. For some reason texts don't show up on my phone. Sometimes they show up a day or 2 later.
     

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