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Help!!! I need advice on 03 ZR900

4K views 28 replies 14 participants last post by  snochopper 
#1 ·
I have a 2003 ZR900 with stock clutching, carbs, pipe, y-pipe, air box with tubes installed. The pipe has a slight dent in it. The sled has a 136 Extension kit, 1.5 inch lug track. I am only seeing 90MPH on the speedo and my gas mileage is awful at 8.5MPG

The sled seems to run fine and snappy on the trail. No bog. I idles real high until I choke it. Idles great cold, when you first start it up.

I don't know if the jetting is stock. I bought the sled used. Never really idle well from day one.

I need some help with this one. I would like to see the top end past 100mph and the gas mileage around 12mpg.

 
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#2 ·
I'd start off by cleaning out your carbs really well and chasing down that high idle issue. With the sled running spay some carb cleaner around the intake boots, crank seals, etc to see if it idles down. If it does, fix that leak first before you burn your sled down.

After your fix that start looking at your plugs and see how she is running. If your pig rich you can start working on jetting which will help your top speed and mpg. DO NOT do this before you find the source of that high idle. If you do have an air leak and you start leaning it out - you will most definitely be coming back here to cuss me out because you melted your motor. You could have a minor air leak that isn't making anything bad right now because you happen to be jetted quite rich.. but as soon as you change that... watch out.

After that I'd put some calls into places like Goodwin to get a good clutch setup for your sled. I'd also talk to other guys with 136 900's and see what they are running. If your a bigger guy, with the bigger track - it just might be a challenge to get to far over 100mph.
 
#3 ·
QUOTE (XtremeCat @ Feb 17 2010, 04:16 PM) index.php?act=findpost&pid=5198709
I'd start off by cleaning out your carbs really well and chasing down that high idle issue. With the sled running spay some carb cleaner around the intake boots, crank seals, etc to see if it idles down. If it does, fix that leak first before you burn your sled down.

After your fix that start looking at your plugs and see how she is running. If your pig rich you can start working on jetting which will help your top speed and mpg. DO NOT do this before you find the source of that high idle. If you do have an air leak and you start leaning it out - you will most definitely be coming back here to cuss me out because you melted your motor. You could have a minor air leak that isn't making anything bad right now because you happen to be jetted quite rich.. but as soon as you change that... watch out.

After that I'd put some calls into places like Goodwin to get a good clutch setup for your sled. I'd also talk to other guys with 136 900's and see what they are running. If your a bigger guy, with the bigger track - it just might be a challenge to get to far over 100mph.[/b]
Yep. she is PIG rich. I forgot too mention that the plugs are always black and oily. I will start looking for the leak. I run 265lbs with gear on.
 
#5 ·
What RPM are you seeing wide open? Have you ever cleaned your APV's? You may have gummed up APV's. Also check and see what clip position your needle is in. You may need to raise the clip to lean it out a little in your midrange. The needle position means more on your fuel consumption than your main jet unless you are constantly wide open throttle.
 
#6 ·
When mine was new the servo motor for the APV's went bad.It still seemed snappy but would only turn 6800 RPM. The powervalves wont open till 7000 RPM. I put in a new servomotor and damn what a difference.Mine will stand the speedo straight up and down. Bet you got an APV issue.Youll need to take the cover off the servo and start the engine and see if they cycle. If not theres a problem.
 
#7 ·
I wouldn't lean out the clip for the midrange any on the 03's, they had a bad mid-range lean condition to start with, and you will most likely burn down when cruising at 60-70 mph, or 6000-6500rpm's, I changed my needle to compensate for this, but have no recollection of the needle number...its on here somewhere though...
 
#8 ·
QUOTE (catspaz8 @ Feb 17 2010, 10:22 PM) index.php?act=findpost&pid=5200164
I wouldn't lean out the clip for the midrange any on the 03's, they had a bad mid-range lean condition to start with, and you will most likely burn down when cruising at 60-70 mph, or 6000-6500rpm's, I changed my needle to compensate for this, but have no recollection of the needle number...its on here somewhere though...[/b]
The richer needle is 9DFH2-58 .......part # 6506-200
 
#12 ·
QUOTE (Smythe @ Feb 17 2010, 09:27 PM) index.php?act=findpost&pid=5199951
When mine was new the servo motor for the APV's went bad.It still seemed snappy but would only turn 6800 RPM. The powervalves wont open till 7000 RPM. I put in a new servomotor and damn what a difference.Mine will stand the speedo straight up and down. Bet you got an APV issue.Youll need to take the cover off the servo and start the engine and see if they cycle. If not theres a problem.[/b]
Thanks. That makes alot of sense. I am only pulling a 7000RPM. It gets to 7000 and that's it.
 
#13 ·
QUOTE (kawiultra99 @ Feb 18 2010, 08:00 AM) index.php?act=findpost&pid=5200832
Thanks. That makes alot of sense. I am only pulling a 7000RPM. It gets to 7000 and that's it.[/b]
i have the same sled, goes like hell to 7100 rpm but wont rev any higher even with a heavy spring in primary, took a closer look at my apv's and one was stuck closed and they are both way out to lunch with the adjustments. Going to fix it tonight and see what happens. I cant even imagine how its gonna pull when i clean them and adjust them! Look them over carefully and adjust accordingly, i believe 38.5mm is the measurement, anybody correct me if iam wrong
 
#15 ·
QUOTE (razer900 @ Feb 18 2010, 09:00 AM) index.php?act=findpost&pid=5200964
i have the same sled, goes like hell to 7100 rpm but wont rev any higher even with a heavy spring in primary, took a closer look at my apv's and one was stuck closed and they are both way out to lunch with the adjustments. Going to fix it tonight and see what happens. I cant even imagine how its gonna pull when i clean them and adjust them! Look them over carefully and adjust accordingly, i believe 38.5mm is the measurement, anybody correct me if iam wrong[/b]
Keep in mind if you change your primary spring - your only changing engagement RPM's. It has NOTHING to do with how many RPM's you turn at WOT. That is going to rest in your tuning, secondary, and APV's if they are dirty.
 
#18 ·
#21 ·
QUOTE (XtremeCat @ Feb 18 2010, 01:11 PM) index.php?act=findpost&pid=5201578
Not doubting you - its just not how it was taught to me. Anywhere you can provide something for me to read up on?[/b]
i dont know of an exact post or anything, all i kno is i did more reading here than i did is school. LOL , do some searches to narrow it down and if theres any questions just ask. The guys here are more than helpful and know there stuff. My sled has never ran better thanks to the guys here
 
#23 ·
I got the 3 turns out of the servo motor when I started up the sled. Servo works. Valves stuck. One very hard to get out. Cleaning now.

Haven't measured the cable length.

I read on Dynotech Research that the Y -pipe adds 5 horsepower through out the power band on its own.
 
#25 ·
If you are running CAT APV oil I would clean the valves about every 1000 miles. In my experience the CAT oil leaves alot of residue. Some of the cleaner burning oils you can let go longer. The other thing that you have to watch for is if the get stuck open when the servo rolls back to close them it will kink the cable and break it right at the servo motor. That happend to my daughters boyfriends sled.
 
#26 ·
I want to address the high idle issue. I just picked up an 02 ZR 800 with 750 miles and the things is awesome. When it is cold it idles nice but once warm when you come to a stop it idles high; you have to blip the throttle or choke it down. I started a topic here two weeks ago and many responded that it was normal. I tend to beleive this as I bought a brand new 04 Viper S and it did the same thing from the day it was new. In fact, this issue was big in Snowtech back in 04 and I remember the cause being the flat slide carbs; design flaw that allowed air between the slides. It seems that most everyone on here has commented on a high idle. Some say it's normal, some say it's an air leak and a burn down would be innevitable if not addressed.

So here is my question to all of you. If you have a very high idle, and you choke it down and leave it, if you had a true air leak from a crank seal or boot, wouldn't she creep back up to a high idle????

I called the dealer that I bought it from and he said that it's a normal condition for the flat slide carbsed sleds. He is the largest cat dealer in the US; Livingstons in NH.....

I am always very cautious and I beleive in preventative maintenance but is this really an issue or not? I have a bumper- bumper season warranty on my sled so if they thought it was an issue, wouldn't they want it back to fix the problem before bigger damage occurs???

Intersted in your opinons in this topic...

BN
 
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