Guys,

I have a 2000 SP500 with about 3k miles on it. Pretty much stock except a K&N air filter. Regular maintenance done religiously.

Within the last couple months, the quad doesn't want to start when cold - cold being whatever the ambient air temp is, even 50-60*F (fairly warm). It seems to turns over adequately fast, but never fires... just keeps turning over (and over and over!). Choke and throttling doesn't help. Once the quad starts up and gets up to operating temp, it'll re-start like a champ... unless allowed to cool off for a couple hours. It also doesn't like to idle until @ operating temp (it'll stall), but I think that's just my idle setting being a little low.

- I've pulled the plug during no-start conditions, it's getting spark.
- I've used starting fluid during no-start conditions, doesn't seem to help.
- The battery was just replaced last year, YUASA maint free, and the bike is kept on a YUASA battery tender year-round. I can go test the voltage, but I really don't think this is the issue.

The quad is now 10 years old and I've noticed that the exhaust is leaking in between the exhaust manifold and tail-pipe (up by the front of the engine, seems the two pipes are held together by a now very rusty spring-loaded clamp). I'm wondering if the lack of back-pressure may be causing the hard-start problems.?.?

I've never changed the coil ignition wire, probably time to do so, but I don't think this is causing the issue either.

Any suggestions on where to start troubleshooting?

The quad sits most of the winter with premium gas in the carb - not sure if varnishing of carb parts may be contributing to the problem. Then again, starting fluid doesn't help....

Other than that, wondering if the starter just isn't turning over the engine fast enough...

This quad has never been "easy" to start in very cold weather (below freezing)... but normally very reliable above freezing conditions. This issue has just started in the last couple months...

Thx

 

have you tried to start it w/ the pull starter when it doesn't want to start to see if it makes any differnce? have the vlaves ever been adjusted? lack of back pressure could have some effect if it's leaking. imo

 

No, I've never had the valves checked/adjusted.
I'll try pull starting it next time I fire it up.
I don't mind replacing the exhaust if that's the problem, but would prefer not to spend the ~$500 unless I have to...

 

first I would start with a good carb cleaning. you would be suprised at how gummed up carbs get... Even if you use premium fuels. maybe replace or even resize you jet. Also you may need to adjust idle just a little, to much and you will have to many rpm when it's warmer out

 

Thanks. Just to be clear, you're suggesting pulling the carb off and doing a full disassemble/re-assemble? Does Polaris/some make a "rebuild" kit for this carb?

Is there any common practice when re-jetting these carbs? Upsize the main jets one size? I can handle the mechanical work w/o issue, but I'm not an expert carb tuner!

 

putting good gas in w/ out using a stablizer doesn't really matter when the bike sitting for long periods of time. gas can start to gumm up after weeks of sitting. as far as cleaning the carb you don't need to rejet or even get a carb kit if there is nothing wore out and it's just dirty. it does require taking it off and dis assembling to clean. how ever if the bike runs fine going up through the throttle then the main jet and circuit would be fine. your start up circuit and pilot jet might be starting to get gummed up. if you don't feel you have the mechical back gorund to do a carb off i would take it to some one who does. how long did the bike sit not being ran?

 

Unfortunately, it's common for the bike to sit unused for months at a time. I live in the city and have to trailer 3+ hours to ride. Spring through Fall, I generally ride one weekend a month + a 1 week trip/vacation. Then the bike normally sits from November through April (generally < 35* F during this time). I try to use BP Premium whenever possible. I bought some Seafoam when the hard start problem started... ran 2 full tanks of treated gas through it since. Hasn't seemed to help.

Cleaning the carb & adjusting the valves are both probably past-due anyway - I'll do both. What do you guys recommend for a quad that sits for months at a time? Turn the gas valve off and run until the carb is dry? I can try and run Seafoam/Stabil every tank - just hard when filling up on the trail, trailering home and parking it in the garage until the next ride.

 

Sounds like carb needs cleaned, while you have it out see if the brassplug has been removed over the fuel screw, this is on the bottom of carb , if brass plug is stillthere, take a 1/8 inch drill bit, drill through the brass, you will feel the bit kinda fall when your through the brass, dont drill the screw underneath, then screw a 1/8 inch sheet metal screw into plug get ahold of screw with small vice grips and twist and pull and plug will come out, screw underrneath should be set at 2.5 turn out from lightly seated.I keep a little seafoam in my machines year around and when I know they are gonna set awhile I add some stabil

 

Hello everyone.. this is my first post (HI! lol)

Im in the exact same boat here... bought an 05' Predator 500 yesterday.

Runs perfect when warm, and starts right up in an 80deg garage (after a day or so). Won't start on starter when cold outside. If I have my friends push me down the driveway pretty quick I can pop the clutch and it starts right up. Runs perfect, even when it's cold.

Just went and bought a brand new battery (other was nasty looking) and a new NGK spark plug (the old one was in OK shape, but gapped to ~.019" vs. ~.035 it should be.)

Did the exact same thing as the O.P. except now I am one step ahead of the OP. I have already removed the carb and it's sitting in my kitchen. Brass plug is still there.

I will clean, and clean sum-more and see what happens. QUICK QUESTION: When you say 2 1/2 "turns", is a "turn" 180 degrees or 360 degrees?

Thanks... trying to help and get help at the same time.

-=Mike G.

 

360,, Im talking about a full turn, remove brass plug and see what it fuel screw is set at, I have seen them totally shut