T
I have read many mixed reviews on this sled and more particularly the engine. Are the issues they have brought on by being beat on or are they general issues with the engine despite the usage?
05 xc 800
- Thread starter Turbotim2
- Start date
The 2005 XC 800 engine is the exact same engine as the RMK, Switchback, SKS, etc. It was the 2nd year of the replumbing of the cooling system in order to get twice the cooling. It is a trail sled so don't even imagine that you are going to do 2 feet of fresh powder without getting stuck all of the time. Most sleds of this age have a destroyed or nearly destroyed left side drive axle bearing. The right side drive axle bearing probably also needs replacement so you buy an EBAY kit that has both bearings. The rear bogie wheel bearings will likely also need replacement at any mileage over 2500 miles. The left front engine mounts also get torn. If you buy a used sled of this vintage, they are probable on the verge of stranding the rider 10 miles from the snow park in any one of a half dozen different methods. When I buy a used sled, I always take about the engine and replace all the crankshaft bearings that show any signs of wear. Better check the compression before you take it apart because they need new rings every 1000 to 1500 miles. Ideally, you want 140 psi to 145 psi compression with new rings and pistons and piston rod bearing.
T
Thanks for the reply,
I have no intentions of riding in much powder, just trails. I guess they don't make things to last anymore, new rings at 1,000 miles?
I have no intentions of riding in much powder, just trails. I guess they don't make things to last anymore, new rings at 1,000 miles?
check the runout on the crank, polaris says 0.004, anything over 0.002 IMHO is getting sketchy. The ves springs will need replacing. Basic maintenance and ride like you stole it.
T
OK, thanks!!
I picked up a rough but running 800 RMK for the track and skid five years ago. Well, even thought it ran, the crank runout was over .01. The clutch weight bushings were junk, and the weights had damaged the spider. But that was a mountain sled with almost 5000 miles. The old 800 "big block" is actually a pretty good, long-lasting motor if the clutch is properly balanced and set up right, and it hasn't been abused. Trail sleds tend to see less wide-open-throttle, so the likelihood of problems is lower. The left driveshaft bearing on that sled was almost destroyed, and I've had to replace that particular bearing on my 600 as well. I've replaced other bearings, but the two in the chaincase and the left jackshaft bearing seem to hold up pretty well.
Here's what I'd check and do: pull the carbs and check the carb boots (had those go bad, can cause poor running, and may result in a lean burn-down), and while you're at it, check what jets you've got and reset the idle mix and air bleed screws per the factory service manual (FSM). You'll probably need a clutch puller, although I rode for a couple seasons before I got one. You can inspect the primary without pulling it, but I don't think you can check the crank runout (that's more of a "should" than a "shall"). Check the oil pump and set it according to the FSM, then I like to drain the oil tank and refill it a pint at a time, making a mark each time. That way you can make sure you're getting the right oil mix by comparing gas burned to oil used. You'll need to bleed the line to the oil pump. At a minimum, grease all grease points on the front suspension and skid; it'd be a good idea to pull the skid, clean everything out, and pump fresh grease in; same on the spindles. For the driveshaft bearing, you can check it by taking the speedometer drive off. You have to pull the driveshaft to replace that bearing, but maybe it's been done. On the clutches, I'd disassemble the secondary, inspect it, and replace the spring, as well as the primary spring. Not sure if this is a PERC (electronic reverse) sled or not, but you may need to replace the secondary rollers or buttons. If it's been neglected, there's a weekend project worth of work, even for someone who's familiar, that probably should be done. For however much you're able to do, look for any weird noises and vibrations when you do start riding it. It may not need anything (if you're lucky), but even a little checking could save you a lot of trouble. Both my sleds were well cared-for, but were also relatively young sleds when I got them. Even if you're not ready to tackle everything we've mentioned, it should give you an idea of what to check. Definitely find a copy of the FSM, look things over, and don't take anything for granted. They EDGE chassis is kind of old-school now, but they're still great sleds and will go a long way if they're taken care of. Even one that's neglected can often be brought back into shape without too much time and money.
Here's what I'd check and do: pull the carbs and check the carb boots (had those go bad, can cause poor running, and may result in a lean burn-down), and while you're at it, check what jets you've got and reset the idle mix and air bleed screws per the factory service manual (FSM). You'll probably need a clutch puller, although I rode for a couple seasons before I got one. You can inspect the primary without pulling it, but I don't think you can check the crank runout (that's more of a "should" than a "shall"). Check the oil pump and set it according to the FSM, then I like to drain the oil tank and refill it a pint at a time, making a mark each time. That way you can make sure you're getting the right oil mix by comparing gas burned to oil used. You'll need to bleed the line to the oil pump. At a minimum, grease all grease points on the front suspension and skid; it'd be a good idea to pull the skid, clean everything out, and pump fresh grease in; same on the spindles. For the driveshaft bearing, you can check it by taking the speedometer drive off. You have to pull the driveshaft to replace that bearing, but maybe it's been done. On the clutches, I'd disassemble the secondary, inspect it, and replace the spring, as well as the primary spring. Not sure if this is a PERC (electronic reverse) sled or not, but you may need to replace the secondary rollers or buttons. If it's been neglected, there's a weekend project worth of work, even for someone who's familiar, that probably should be done. For however much you're able to do, look for any weird noises and vibrations when you do start riding it. It may not need anything (if you're lucky), but even a little checking could save you a lot of trouble. Both my sleds were well cared-for, but were also relatively young sleds when I got them. Even if you're not ready to tackle everything we've mentioned, it should give you an idea of what to check. Definitely find a copy of the FSM, look things over, and don't take anything for granted. They EDGE chassis is kind of old-school now, but they're still great sleds and will go a long way if they're taken care of. Even one that's neglected can often be brought back into shape without too much time and money.
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The center bolt that holds the lower chain case gear on, needs to be checked every year and use thread lock. The left front engine mount needs to be checked. New pistons and rings may be in order if the compression is below 115 psi. Blow out the four oil injector holes to the carburetor and crankcase, with compressed air.
T
Does anyone know of/have the manual supplement for this sled? I found one for the 03 on the Polaris website but none for this one. Thanks!
There was an '04 deep snow manual back in the day. An excellent manual to have. Don't know where you could find one these days, maybe ebay. Everything you'd ever need to know. Your getting good advice here, lots of guys ran bb 800's back when, some still do.
T
It looks like the fun has ended already. Went to bring it in garage to go through it and it died after 100'. Acts like it isn't getting gas. Is there a fuel pump test? The fuel valve is open.
On the Polaris Liberty Edge engines, the oil slowly drains into the engine when it is not running over the summer. Consequently, when you finally fire it up again, it has to burn through all the oil that is now sitting in the bottom of the crankcase. In that process, you have an increased likelihood of fowling the plugs. Once they foul, the internal electrical resistances can change, making that plug now useless. So obviously, slap some new plugs in that bad boy and don't hesitate to use some starter fluid to start the engine and fuel pump working. Fuel pumps need to be rebuilt if it takes more than 10 pulls, when the engine has not been run for a week. A quick cowboy rebuild can be done by opening up the fuel pump and flipping the nickel size round diaphragms, upside down so you have the now smooth face contacting the round valve to make a good seal. Don't wrinkle or bend the round diaphragms.
In addition to what @whoisthatguy mentioned, it's possible for the diaphragm in the fuel pump, between the side that's connected to the crankcase and the side that's exposed to fuel, to rupture or leak, allowing raw gas to seep into the crankcase. There are two drain plugs on the block underneath the y-pipe. Take those off and see if you get a bunch of gas or oil come pouring out. You'll typically get just a little oil/gas mix oozing out if all's well; if you get a bunch of gas, check the fuel pump first (it can also be carb-related though). If you get a bunch of oil, check the oil pump and throttle cable settings. I had an old sled where the fuel pump went bad, and when I took the block drains out, it dumped a good 4-6oz out. So yeah, could be fuel pump (leaking gas into the case, or not pumping), could be half-full of oil from seeping past the pump. Could be other things, but start there. Also, as mentioned, you've probably got fouled plugs you'll have to clean or replace or it's not likely to start even once the problem is fixed.
T
Well the plugs were fouled, I have new ones on the way but in the meantime, I cleaned the old ones and got good spark. It fired up. It has also been in the warm garage today so I am not sure if something froze while it was outside.
Good news is I am getting 150 psi in both cylinders, got the sled ready otherwise so as long as it keeps running with new plugs then I should be in business.
Good news is I am getting 150 psi in both cylinders, got the sled ready otherwise so as long as it keeps running with new plugs then I should be in business.
