2000 XCR 800. Stock engine. Airbox Mod, stock clutching with new springs aligned perfectly. New mounts with SLP torque arm and 420 mains with good wash. OK here it is... When running on hardpacked trails it runs like a raped ape. Especially from a dead stop. Pulls 8150 rpm perfect. As soon as i get out on the lake in the deep stuff it runs like $hit. If I stop and pin it it will pull the proper rpm, but if I let off or pin it from a cruise power setting it fall on its ass. I can cruise at 6000 rpm and when I give er it will only top out at 7000 or so. This has to be a clutching problem? Right? I mean how can it run perfectly on the trail and not run in deep snow??? Help please... at wits end. 8

Have you checked the buttons for the helix?

Worn belt ? What belt ? polaris ?

weak spring in driven clutch, try wrapping it into the next hole, sounds like its shifting out to fast,and not back shifting. i would try a new belt first thought.

oops, wrong thread.

Sounds like clutch to me.....but I Had a similar problem with an old indy 500 with an aftermarket pipe. Turns out it stuck out of the bellypan too far, and when you got into some deep snow it basically plugged the pipe.

I know you said "new stock springs" but which one are you using in the secondary? And which position is it in?


Don

Almond round primary, Silver/Blue secondary with R12 in the second hole. All new parts... Polaris 1075 belt. Sometimes when cruising on hard pack at 6500 rpm or so it will do kind of the same thing its doing in powder but nowhere near as bad. When you pin it from cruise it will pull to 7500 hesitate for a second and then pop up to 8150. I am going to try a new belt and see if that cures it. If not I will put some more tension on the secondary spring. Maybe I got a bad one from Polaris... Any other ideas? Thanks 8

Years ago same sled, sounds like the same problem. It's been a while so I'd have to quiz Brian to confirm some of the details, but here's the story. New 2000 XCR800, pulled RPM on the hardpack, but run it in even a little bit of powder out on the lake and it would only tach out to around 7500. If you ran into the snow at WOT it would usually hold proper RPM, but if you backed out of it, then got back on the throttle, there you were stuck at 7500 again. If you came to a dead stop and pinned it, most of the time it would rev out properly to WOT, but if you rolled into it gradually or backed off for a second - 7500!? Our tech spent a lot time screwing with the clutching and just about everything else. Swapped out all the ignition parts, I think we even changed the crank just in case it was going out of phase under load. Spent a lot of time on the phone with Polaris too. After way too many hours we determined (and this is hard to believe) that the damn thing for some reason was going rich but just on the PTO hole (I think). We figured it had something to do with the sudden drop in coolant temp from running in the deeper snow making the thing go rich enough to lose some pipe temp. I think that ultimately what fixed it was we either just dropped the needle or maybe dropped one MJ size in just that one carb (pretty sure all we did was drop the needle). I know it sounds pretty far-fetched, but if you are at you wit's end, it could be worth a try. I'll talk to Brian on Monday and make sure I've got the story straight, but I'm pretty sure that I've got it right. I have never even heard of an XCR that did this since until I read your post.

Un-plug your TPS and try it.

that sounds just like wut my 2000 xcr 800 is doing also cuz my egt reads low on the pto cylinder everytime i pin it and after a hesitation it comes outta it sometimes! i'm for surely gonna try the jetting!

My sled does the same thing I think. Runs 8100-8300 plus on the track confirmed by Madcow. Ran it in some kinda weird 5-6" damp powder up at Rush lake and could only pull like 7500 rpms. It was pretty warm out but there was two of us on xcr'8's and one guy on a healthy 600 with an ultra bottom and they were running fine. Maybe its always been this way but not sure now. up to now I havent paid attention as it still feels pretty strong. Pretty humbling deal to ride his tho.

Anyways, I am going into the powervalves just to take a look and maybe try a new primary spring. Word is from a couple guys is to shy away from the almond square and go with something else as presumably they get weak? Fiik. I was told what but forget now. If Madcow sees this post he will surely comment.

Please post if you figure it out.

I got 2000 mi. on my almond round now and there is nothing weak about it. I still say it sounds like clutching, secondary issue?

When this happens, hit the kill button, stop, and remove all three plugs. This should help to identify whether it's jetting.

Big mains like many like to run, could easily be fouling the richest cylinder on sudden wide open throttle at lower speeds and high track loads. Incidently, in my testing, on my stock 800 XCR, a Tempa Flow won't affect the main jet sizes at WOT, just the midrange at part throttle.

Phil

You would be surprised about how much tension a spring loses, I have a Rimac spring tester, every new spring I get, I check at both engagement length and full shift length, even several of the exact same part number always check slightly different, I check them again after each season of use, eveyone of them has lost some tension, even the titanium springs lose some, but silicon chrome springs lose about 15% after 1000 miles and get worse the longer you use them.


Don

THERE IS NOTHING WRONG WITH THE SQ. ALMOUND BLACK SPRING, BACK WHEN THEY FIRST CAME OUT, THEY HAD A BAD BATCH, I HAVE USED THEM FOR YEARS, STILL DO IN ALL MY SLEDS. I CHANGED OUT THE ONE IN MY SONS 99XCR8[MY OLD SLED] LAST WEEK ,3 YRS, 1500 MILES, STILL WAS PULLING 8500. HAD TO REPLACE BUTTONS IN DRIVEN SO PUT IN NEW SPRINGS. ALSO REPLACED GRAY DRIVEN, AND 53-36 HELIX. GOES TO 83-84 WHEN YOU STAB IT, RUNS OUT TO 85-86. EVERY TIME!

My brother took my xcr 800 to a radar run today in norwood and the thing ran pretty good. he took the pto side carb needle and dropped it down one notch so the second from the top. thing pulled 8 grand but no more and it should spin faster than that. clutching is 62 grams, almond round, blue orange secondary spring, 50/36 stock helix. the primary is a comet 108 exp. jetting is 400 mains across the board. the egt wuz reading 2 greens 1 green and 1 green so she wasn't running hot in that pto cylinder.


any ideas guys

There is 2 square springs, the almond/black mentioned above, rated at 165-310 and an almond square , rated at 140-330, same as the alm.round. Its the latter thats superceded by the almond round

I got a Rimac too, I'll check it this week. It was dead on when new and I always check my used ones to see if they are close to spec too. The square wire almond was way way off at 1000 mi. of use but the round wire seems to be working fine and is why I assumed it still has very close to spec tension.

So the almond sq. spring retains tension less than the round?

From what I've seen, mine was sacked at 1000 mi. so I switched to the round wire.

Thanks Tripplethreat. Thats where I am going from here. A new almond round spring and going to give the valves a peek. Hope to have it up to snuff for Hackensack.


Anybody have a thought on what hole the secondary should be in? Everything pretty much stock.

my xcr did the same thing at one time. turns out the oil pump was to rich.
you can tighten up the secondary one hole and see what it does.

like patriot said. check your plugs and wash in phases. drive at low speed for a while stop and check plugs, and wash, then drive in the mid range for a little while, stop and check plugs, then hold her to the bar for 1000' burts's and check plugs, make note of the day time temps you are in.

I always ran 420's with the needles dropped one position.

I had good luck with my stock square spring? it might have gotten a little weak, but not any differently than any other spring i have had.

zrx, that was weird snow, but great to test in. lots of spin with a random hit of traction once in a while, that really tests anyones setup. you just have to much weight for them conditions. during spin it overshifts, then the track hits some decent snow for traction and hooks up. but the clutching cant backshift very well with them bigger weights, so for an instant it pulls the rpms down, and before the clutches can backshift and he engine get back up to rpms you are out of room.

your sled is real close i would drop in the 420's and drop the needle one spot and then try it out.

Well did some more testing today...

Unhooked TPS sensor. No change
Killed engine when it bogs. Plugs look good

Belt temperature seemed high and when pinned engine tone would kind of pulsate up and down just a little. It almost seems like the belt is slipping when it gets hot. When it hits 8200 RPM it pulls hard enought to ratchet the track a little. I really think this sleds engine is running fine. I think more and more its in the clutching. I tried the spring in the 3rd hole and it didn't cure the problem. I did notice that the belt deflection is a liitle off at 1.5" on the 5 setting. I tightened it up to 4 to get it back to 1.25". I am going to get a new belt tomorrow just to rule out the belt being worn or stretched. Any other ideas guys?? 8

Double check those motor mounts and straps again. The motor could be twisting around and screwing up clutching???

I found that my center distance is a little over 12". How do I adjust that back down to 12"??? I am assuming that you can shim the rear engine mounts... 8

I meant to say that the distance is shorter then the recommended 12". I tightened up my torque stop and push arm. This got me pretty close to the 12" center distance. Also put on a new belt and reset the deflection to 1.25" Hopfully this will solve my problem. I really don't know what else I can do... 8