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2008 Polaris Sportsman 500 EFI HO, 4x4 won’t work in reverse
By
Enad Nessumsar, in Polaris ATV Forum
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Similar Topics
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By Ed Zeppeli
Hi all,
I picked up this quad after the previous owner couldn't get it going.
The issue is that I can't get it to fire at idle or at all.
I've...
- replaced plug. Decent blue spark. Also tested with spark tester inline.
- rebuilt the carb. PO had already bypassed vacuum lines from petcock. There's fuel at the cylinder
- Checked compression with new gauge. reads 190 psi
- cleaned all contacts I could access.
- am currently jumping with car battery. Solenoid jumpered.
- checked cam timing at TDC and adjusted valve lash
- put gas directly into cylinder to see if it will fire at least momentarily
Motor turns over well. Plug gets wet.
Motor may fire once or twice but smokes through exhaust a bit as if it's trying to fire or combusting.
This leads me to suspect timing. As mentioned I checked the flywheel mark versus cam marks. Perhaps someone has been in there before because I can't find a 'T' on the flywheel but there is a very visible paint mark which aligns with TDC position on piston. Possibly a slipped flywheel/woodruff?
Is it possible that if it had seen previous repairs, that the timing could still be off? I'm reluctant to dig into the flywheel/stator area if there's something else I could have missed but all signs point me to that area. Would a bad CDI cause spark timing to be off?
Anywhere else to diagnose incorrect spark timing?
I've scoured these forums and elsewhere but I'm posting just in case there's something I've overlooked up until now.
Thanks very much for reading!
Warren
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By AimlessMoto
Hey guys, new here, but haven't found ANY answer to my specific problem on a Suzuki dedicated ATV forum, so here's to hoping!
I acquired a 95' Quadrunner 250, 4x4, (LT4WD) for practically nothing with no spark. The PO had tossed in a used stator which didn't fix the problem... so I went all routes (though cheaply) to narrow down the initial problem of no spark.
Plug, coil, CDI (caltric) and stator w/pickup (caltric) were purchased and installed. And it RAN, but bogged horribly and would not rev past 1/4 throttle.
I checked fuel flow, vacuum lines, all the normal stuff, no issues. I decided to check the valves and cam... well, there was one problem. The cam was 1mm under the lowest spec in the manual. So, in-came a new cam, Stage 1 Hotcams... also threw in a new set of shindy valves, lapped them, replaced the valve seals, and the timing chain.
Back together again (w/stock airbox and new oiled filter). Now it idles even better, still boggs at 1/4 throttle, but will rev past it if you hold the throttle open for a second. Ahaha... success!
So I was able to ride it above 1/4 throttle once I had momentum... could shift through the gears, all was good as long as I kept it over 1/2 throttle. Took a long enough ride to break in the cam properly at least so I won't have to worry about that.
Now, I start fiddling with the carb. It's clean as a whistle, stock, with stock jets (new replacement Mikuni jets). Same problem.
I start thinking, maybe this is fuel related and the bike is having an issue transitioning from idle jet to main jet... so I LOWER the needle by raising the clip 1 spot. Now it revvs up in neutral with no bog, but it boggs about the same trying to ride it. So I move the needle down again with the clip on the top slot. Better, but still has a bit of bog at 1/4 throttle.
The last bit of advice I got was to ditch the CV carb... so I sprung for a brand new Mikuni VM30-83 round-slide. Bolted it up, blew into the vacuum tube to fill it with fuel (no vacuum port on this one) and she fired right up... but there is still a bit of bog, it's just masked by the fact that I'm not waiting for the vacuum diaphragm to open.
So I feel like each little step brings me closer, but not perfect. I'm now wondering if this is still in-fact a carb tuning issue (I have some jets I can fiddle with and maybe lean-out the idle jet a little.) OR if the cheap-a** Caltric Stator/Pickup is what's causing these issues.
I have a 95' KingQuad with 400 miles on it... like new.. runs like a top... I've tried both the stock QR and the Caltric CDI boxes on it, and it revvs up and runs like a champ.
The only unknowns between the two systems are the carb, and the stator/pickup. My next step in troubleshooting is to rip apart the King Quad and test it's CDI on the Quadrunner... but considering there is no change to how it runs I doubt it will lead to a solution.
HOWEVER... I tried the stock CDI just recently after running the Caltric this whole time, and the bike runs like garbage. Hardly idles, and won't rev up at all. So, that is my one smoking gun telling me that it's either the pickup coil or the stator itself.
Has anyone had a problem even CLOSE to this? I can't image the carb would be causing this many issues, especially going to 2 different ones, both with stock jetting to OEM, and exhibiting the identical symptoms... the only change is when different CDI's are plugged in, or when the needle valve leans out the mixture.
Also, I checked the piston, rings and bore when I had it apart and they're like-new... no scoring, rings are loose, cylinder is still round and has honing marks still int he bore. Stock piston, stock bore size and it has 160psi compression. Battery is brand new, and I've tried 3 different R/R's, none of which change any symptoms, but slightly vary the charging voltage by .2-.5 of a volt depending on which unit. Also tried a new coil which changed nothing.
ANY help would be appreciated. Too much invested to not get it running right.
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By Ajmboy
Just got this one and am sharing...
Visit 4wheelparts.com Use Code: POLARISORV at checkout *Exclusive offer ends 6/17/19 at 11:59 pm CT
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By Steve Simpson
Any suggestions on where to buy new parts want new jug piston rings would like to go wiesco big bore
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By joninak
Well, it overheated then started blowing white smoke!!
I have it torn down & the cylinder appears to be warped. Going to have the head checked out next but in the meanwhile... Does anyone have the torque sequence/specs for the head bolts??
TIA
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By weblex
Problem: The ATV starts and runs at idle perfectly. But as soon as I open the throttle, the engine starts to slow down until it stops. On the attached video you can hear the sound of how it works: see video below
Prehistory: there is a Polaris Sportsman 500 1998, which for about 1.5 years stood in repair, including also replacing CDI with one taken from the same ATV. Finally, the vehicles were on wheels, traveled several kilometers and overheated - forgot to fill the antifreeze Came back home in small moves. The next trip started well, but after 10 km there was a feeling of a small drop in power (even as the vehicle got warm completely) but still drives. Next trip - the situation is repeated. The next test of ATV through time and a huge loss of power from the very beginning. The engine sneezes, does not want to go more than 5 mph.
What has been done: the carburetor has been replaced with a new one (inexpensive, $ 40), a new spark plug, a new ignition coil, the engine head has been removed, the piston is in good condition, valves were corrected - but the problem was definitely not in them.
Ignition control unit is suspected. Who faced similar? Please help in solving the problem.
Thanks in advance.
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By Paul Maple
I have a 1999 Sportsman 500, it was running fine, than started to lose power in the winter, I adjusted the idle screw and away I went, than a few weeks ago it died, I have found that i am flooding the engine, compression was at 70PSI and due to the compression release mech. i assume i am good as it compared to the same PSI on a 2000 sportsman 500 i have. i cannot start the atv unless i go full throttle and it starts an runs for about 30 sec than dies, again it is flooded. i ordered a new carb off ebay as i could get one for around $40. put that in same issue, i have checked the timing, (good), valves out of adjustment i adjusted to .006 still same issue, i have found the exhaust lobe and rocker arm to have some wear, i have ordered new ones, but am looking for any other input in this area as well. would the exhaust cam and rocker arm cause the engine to flood? i have used a bore scope and the piston liner has good cross hatching still? any input would be great.
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By Zacharia Maisonneuve
i have a 1993 timberwolf yamaha and the compression is good and lights work but for some reason the electricity is not going to the spark plug(s)! i got a friend to check it out and they said its no use but im not giving up! please help with this!
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By Ashton Crawford
Hello everyone, i have 2000 Polaris Trail Blazer 300 I’ve been stumped on for weeks. I’m having a lot of issues starting the quad. I cleaned the carb spotless because I thought it was a carb issue and bought a new fuel line because it wasn’t getting fuel. The carb gets fuel perfectly fine now but it won’t start. The spark plug I a little worn out but it’s good enough for just one start. The only time it does “start” is when I spray starter fluid into the carb. But it never stays on. It’ll start for a bout a second then just die out immediately even if you’re giving it some throttle and the choke is on. I have no clue what I should do. If you need more information, have questions, or have any slight idea what the issue would be and how I could resolve it. Please reply ASAP. Thank you.
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By Hunter Aldridge
Some times I get spark some times not can ride then it just dies and wont get spark it has new cdi box and stator but I don't know if it has the pickup coil I'm at a loss
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