500xcsp running poorly - Snowmobile Forum: Your #1 Snowmobile Forum

45th500xcsp · 01-17-2013, 03:04 PM

Hello, new to the forum, joined because I have an ongoing problem with my 2000 45th anniversary 500xcsp. It starts great but seems to load up while idling and sputters/bogs with an occasional backfire when taking off. If I take off from a stop and pin it, once it clears out it will take off great and run wide open but if I am running midrange, partial throttle and pin it, it is very slow to open up or it will not open up at all. When running wide open it will sometimes also lose rpms and stay around 7000.

Symptoms seem to be worse the longer it is ridden, if shut off for a bit along the trail, and started back up it seems to run better for a while.

Things I have done:
Cleaned/checked VES
clutching: 10-54 weights blue/silver primary spring, secondary: r8 helix, sliver/blue spring in #2
compression: 110 both holes
timing checked
carbs cleaned multiple times, needles at #2 clip (runs worse in #3), main jet: 410, While up north last weekend I tweaked the fuel screws some to about 2 turns out and it ran much better for the day but the next day ran worse again.
TPS is at 3.9 volts
Replaced reeds
It is not getting very good fuel or oil economy.
Gearing is stock
I am getting some fuel in the airbox, not sure if its more than normal or not

Sorry for the long post, getting extremely frustrated at everything I've done with no success. Thanks for the help

**RJ Gleason** · 01-17-2013, 04:10 PM

When you did the carbs, did you check that the chokes are functioning properly and adjusted right?

45th500xcsp · 01-17-2013, 04:15 PM

Yea the chokes are working fine

**RJ Gleason** · 01-17-2013, 04:24 PM

Almost sounds as if it's running fat in the low end.
Although, at 110 psi, it's getting low, your good running minimum would be 120 spi.
With the miles and age, it might just be time for new rings.

45th500xcsp · 01-18-2013, 08:28 AM

It does seem rich on the low end, just not sure if that would also effect my midrange? I know 110 isn't ideal but by the way it starts and runs good occasionally I wasn't leaning toward a rebuild, but it is one of my last options. Could weak clutch springs cause my midrange problems? As they get hotter the get weaker?

white lightning · 01-18-2013, 11:31 AM

When u say "hotter and weaker" are you referring to touching the clutch and it feels hot? If it is .. it means your belt is slipping on the clutch, which makes it hot to touch. Also that would bring your revs down. 110 in compression isnt awfully loss and I dont think thats the total culprit why youre pulling 7k revs. Per your post .. it sounds to me while youre in the midrange and u pin the throttle, youre not backshifting to bring your revs back up. My strong guess would be to pay more attention to the 2ndary. WL

**RJ Gleason** · 01-18-2013, 11:32 AM

Check the air screw setting, most Poo like to run with them set at 1 turn out from bottomed. Then when you make any adjustments from that point, do it on 1/4 turn increments.

45th500xcsp · 01-18-2013, 11:39 AM

What should I look at in the secondary? I have cleaned it and put the factory r8 helix in (person before me had an r3 in it). I tried running the spring tighter (in the third hole) and it did seem to help with the midrange acceleration. The sled has 3500 miles on it, would that be enough to weaken the spring?

white lightning · 01-18-2013, 11:53 AM

With 3,500miles - yes the spring can be weaken and how does the buttons looks? May have to replace those - You also may have to change the primary spring if it has 3,500 miles on it as well. WL

45th500xcsp · 01-18-2013, 11:59 AM

I just replaced the buttons, Ill look into getting springs now. Clutching problems would make sense since the motor doesn't bog or pop midrange, It just doesn't accelerate.

edge800ves · 01-18-2013, 12:08 PM

Make sure your weight bushings in your primary arent shot too, they shouldnt have any play

white lightning · 01-18-2013, 12:14 PM

Thats MY guess why the previous owner dropped in R3 helix because of it. WL