King Cat Carbs

[800CatRider]

I recently purchased an 04 king cat 900 and have been told that they have a tenancy of running too lean and seizing up. I was wondering what you guys run for carb settings on your king cats.

Thanks

 

[800CatRider]

No responses? any input would help.

Thanks

 

[lgn1738]

hey workin on gettin my jetting dialed. also have 04 m cat 900 162 speedwerx y and pipe boysenn reeds gutted air box, right now have 55 pilot and 430 main felt rich this weekend on mt baker was at 4-5k i think

 

[Rixster]

WOW 430 mains that is big !!! but I am used to jetting for 9000-11000
The lean spot is more of a ignition thing. Cat runs super hot in the mid range. If you are riding down a road and a constant throttle you WILL burn down the motor. It doesnt really matter how you jet, there is no getting away from it. Just make sure you move the throttle A LOT when riding a road for any time at all.

 

[lgn1738]

ya thought id start a little fat and work down cheaper than the other way haha

 

[mp_2009]

jetting

i ride 6000 to 7000ft and i run 400 410 with twin slp ceramics

 

[spomey]

Everyone will say I am crazy but here is what I have ran for jetting since 04 and I'm still fat and I hav3e two buddies running twins with the same setup

CPI single pipe
VF3 reeds
.015 milled off the heads (135 psi compression)

50 pilot
needle in the middle
350 mains

the three of us ride at 7-10K feet. one extremely cold night coming down my buddy running twins sqweeked a cylinder, so he went to 360's.

 

[800CatRider]

Well we got some snow this weekend and im gonna be heading up to the mountains this weekend to test it out. I'll try some of these ideas.

Thanks

 

[diirtbag]

like was said vary the throttle constantly except for wot,i am running bored carbs with 500 mains,w/timing key on cutler 1000 w/high compression heads.

 

[Idcatman1]

Quote:
Originally Posted by Rixster
The lean spot is more of a ignition thing. Cat runs super hot in the mid range. If you are riding down a road and a constant throttle you WILL burn down the motor. It doesnt really matter how you jet, there is no getting away from it. Just make sure you move the throttle A LOT when riding a road for any time at all.
To start I agree with Rixster. I have played with needle position and richer needles and all I have been able to do is make my engines run like crap in the midrange, so I have come to the same conclusion. I have posted several times about how all the Cat 800 and 900 carb engines I have ever seen have a blubber at low speed. To take care of that I run 30 or 35 pilots depending on elevation and leaner throttle slides as well. I either use 3.5 s or cut the stock 3.0 s to just shy of that. Idcatman3 and I have come to the conclusion that most of the people who have trouble with the hot spot have to clutch high to get around the low speed blubber. Because of this they are trying to run in the hot spot at trail speeds. We think the reason we have never seized an engine in that midrange hot spot is once I got the carburetion cleaned up I was able to clutch for a lower engagement and lower running rpm at trail cruising speeds. The hot spot seems to be from roughly 6000 to 6500 rpm. A lot of the stock 900s I have ridden seem to need to run there in order to go cruise at 30 to 40 mph on the trail. My sleds will run that speed at 4800 to 5800 rpm. I have noticed watching the egt that temps will go way up after about 6000 and start dropping off again after about 6800. I use a stock blue Cat spring 0646-148 and about 63 gram weights in a stock 900. I use 67 -68 grams in my 975s. I am running I think 350 or 360 mains and have run as low as 330s in a stock 900. We ride at 5000 ft plus and I have ridden as low as 3000 with only jetting up the mains a couple sizes.
Hope this helps, will be glad to discuss more.

 

[800CatRider]

That will help a ton. I purchased an 02 Mountain Cat last year but it was EFI and that sled was a blast. At first I was afraid to pick this king cat up because it was a big carbed engine. Ill try the settings you suggested and ill keep in contact with you if i have any other questions on the king cat.

Thanks

 

[ccpowder]

Wish I could remember how I had my '03 (SLP single, Struthers porting, V-Force reeds) jetted cause I could hold it constant at any position and never get to hot. I tried it with EGT's and it would always level out at a safe point. So, I think you can definately jet it out unless the timing was changed for '04.

The best bet is to not hold it constant, something most people will tell you.

 

[woodtick]

jetting

I run a 900 king cat. I have the bases cut off of the cyclinders .020 . This changes the port timing to produce more low end power. It has 150 lbs. of compression, with .055 squish. I have no timing key changes from stock. I am running between 7-9000 feet most of the time. And try not to ride when it is 20 below or lower. Run 380-390 mains with 50 pilot, and needle in the next to the top groove. If the temp. drops off to below -10 I drop the clip one grove down. I always make sure I warm up this engine before I move it at all. I have yet to lose one due to lean condition. I do think the pilots are a bit big, but I just have the air screws out to 2 turns. Also there are fuel screws on the carbs. They control only just off of idle to about 1/8 throttle. If you are having a problem just off idle check to see if you have these screws out to far. I have mine at about 1.5 turns. I believe these screws are a kind of power jet for the low end. Also I have noticed that after it warms up I turn off the water to the carbs, this will help with the blubbering. Just my 2 cents worth.

 

[KMMAC]

I thought at some point on here someone had used ZR needles and needle jet, not sure now if it was the stock ZR setup or not, it was quite a while ago.

 

[Coldfinger]

I have 1,900 miles on my 2004 900 carbed sled. Never had a problem but maybe that is because it is all stock and/or maybe I'm varying the throttle enough and/or maybe I'm just lucky.?

 

[icr]

I was told the needles from an 03-05 vertical escape 800 is this ticket for eliminating the hot spot. I bought a set and ran them through a caliper...they look like they'll work but I haven't had a chance to get it on the snow and find out for sure.

 

[chevota84]

If you run twins it will make the lean spot worse. I run a 430 main in the pto side and a 440 in the mag side with slp twins v force and no air box. Thats from 3500k to 7000k. On the little trail riding we do I just blip the throttle every 5 or 10 secs to keep it happy.

 

[diggerdown]

I've never understood how some of these guys run such big jets and are able to hold R's at full throttle. At 20*F and 9000' I run 340's with no problem. With 360's I could'nt get my egt's over 1050 wide open! Mid range runs about 1150 to 1200 with the clip in the middle. I have a speedwerx single and a 13/1 head.

 

[chevota84]

I spin about 8500 rpm's on a climb according to the notoriously inaccurate cat tach.

 

[800CatRider]

I spin about 8500 rpm's on a climb according to the notoriously inaccurate cat tach.

I'm running the same jet settings you are and i took it out yesterday and it ran flawlessly. I wasn't losing any power but i wasn't getting too hot. The mountain we were riding was about 6000ft. I might get an altitude compensator for when we ride the big hills, but for now i wont touch a thing.

Thanks