The ’91 350 has recently developed a problem where it idles fine only once in a while but usually dies, it doesn’t seem to be temperature related as it’s so unpredictable, I’ve rebuilt the carb. And still have the same results,, a friend suggested it may be a bad reed valve, … Any thoughts or advice would be appreciated

The ’91 350 has recently developed a problem where it idles fine only once in a while but usually dies, it doesn’t seem to be temperature related as it’s so unpredictable, I’ve rebuilt the carb. And still have the same results,, a friend suggested it may be a bad reed valve, … Any thoughts or advice would be appreciated

The ’91 350 has recently developed a problem where it idles fine only once in a while but usually dies, it doesn’t seem to be temperature related as it’s so unpredictable, I’ve rebuilt the carb. And still have the same results,, a friend suggested it may be a bad reed valve, … Any thoughts or advice would be appreciated

I have a Polaris Trail Boss 250 4X4, That I have been fighting for a week to get the carb adjusted right. Just figured out the problem earlier. ETC. I have the carb adjusted decent, but the problem is it backfires coming back down from a rev up. SO I hold in the over ride button, and the idle smooths out, no backfires after rev ups. I tried both ways probably 15 times each. I am positive its the ETC. What I want to do is Bypass this switch, but I am not sure how to go about it. Any help would be appreciated. Thanks

Hey folks, i’m new to this site so any help would be appreciated. I have an 01 xplorer 250 4×4 that was given to me. The engine was locked up. I pulled the jug off and looked down into the crankcase and noticed some rust. I was able to get it to rotate about a half turn. I guess my question is, is there oil that should go in this crankcase and if so what type and amount. Also is there anything I can put in to let sit to see if it will free it up. I had someone tell me one time that they have put diesel fuel in them for a few days to get them to loosen up. I’m just trying to keep from having to pull the case out and tear it down. Again thanks for an help.

Rather than retype it, I’ll just direct everyone to my original post.
http://www.polarisatvforums.com/foru…-sticking.html

This thing is driving this old man nuts………….

I think its about time i ask for some help. getting in over my comfort level. Bought used 2 yrs ago. Cant remember how man hours on it, but not many. invoice says 800km when i got it. maybe i have put several hundred more on it.very little use, easy trails. never sunk. stored under cover. mild climate. so pretty new condition with light use and not swamped.
Quad ran fine, parked at friends house, then no start. codes 51, 51. had previous wiring issues so checked all of the electrics. replace the TBAP harness with OTB harness (found 3 worn wires). at one point had a code 22. reset the computer. no codes now. Fuel pump runs and there is normal appearing fuel at the injectors (i dont have a pressure tester for the rail, and i cant get the cap off anyway). There is spark on both sides. Changed the plugs, no help. tps, tbap and cps all good to the wiring harness at the CDI plug. Checked, charged and jumped the battery charges to 12.6 or so and discharges to 11.6 or so under cranking. it turns over easily but does not burn the fuel i know is going into the cylinder even though i know there is spark. thinking it must be out of time i had a look at the flywheel/timing ring key way (woodruff) and appears ok – did not remove the flywheel off the crank (was missing a bolt for my puller)….so all of this done 3 hrs from where i live and ran out of time. I was thinking the timing must be off. but as far as i can figure it can only be changed by computer.
Now i have the quad at home. checked the compression and 190 on the left and 65 on the right. so now i am looking for a mechanical issue. Still no codes. Ok so i pull the head off thinking i might have a blown head gasket ( btw i did notice a slight drop in the coolant reservoir) oil still looks normal. there is some mild scoring on the rear side of the pistons – about 2-3x worse on the 190 side (left), but too mild to catch a finger nail on. looks like that was coming from the casting edge on the case – is rough. the scoring does not progress all the way up the piston and is not scored at or between the rings. the rings look normal not scored and move freely. there really does not appear to be any blow by. the scoring on walls of the cylinders are even more slight and also is not all the way to the top. so mild i really dont think honing will make any difference. there is really not much to see with the valves, they all appear to be moving, nothing looks excessively worn. the under side of one valve had some light rust again on the good side (190). i can see the cam through most of the rotation and it looks ok, but i don’t really want to go deeper in. turns over nice and smooth, no click, crunch or grind. So … now we get to some questions.

1. could it have just been the head or base gasket? and would i see evidence on the gasket? it looks normal to me.
2. if the scoring is worse on the side making 190 lbs, could the scoring on the 65 lbs side really be the problem? do i need to replace the cylinders, rings and pistons?
3. could this be a valve problem even though they are hydraulic? FWIW they were just very lightly ticking and sounded very normal to me when the bike was running. stuck open exhaust? i know i should have been watching closer when i took the head off. they appeared to be going up and down nicely and evenly.
4. what else can give me low compression?
5. is it surprising to not even get a cough or a sputter with all this. i would think the 190 side would fire and it would try to run? do i have 2 problems?

THANKS FOR READING! i will try to get some pics of the pistons, and valves

New member here with a Scrambler 400. I purchased a Scrambler 400 for my GF with a blown motor and replaced it with a rebuilt motor out of a Xplorer 400. Well since the wiring was different on the new motor I just used the CDI box out of the Xplorer on my Scrambler. Now my problem is that once the quad has been running for a while and the CDI box warms up the quad doesn’t want to shut off. I figured it is the CDI box because it makes a weird buzzing sound when i put my ear next to it. The quad doesn’t have a problem shutting off when it’s cold started just after it’s been running for several minutes. So far I’ve tried two different brand CDI boxes off eBay both new in the box and none of them start the quad. I then hook my old CDI box up and the quad starts right up. What’s the deal? Everything is hooked up just the same.

Ok, I have a 2003 Magnum 330 2×4. Owned it since new. Never had any engine problems, never been used for nothing other than general farm use. Really haven’t had any problems. Anyways… It ended up coming to a point where it didn’t get used. So it just sat in the barn for over a year, not touched. Ran fine when parked. Finally felt like using it again. Pulled it out, battery was obviously shot, got a new one. Solenoid was bad, replaced that, now it would try to crank. So I changed the oil and rebuilt the carb and put in fresh gas. So it would crank up and run good, idled nice, no problems. Oh I also checked the valve clearance when I did an oil change, they were still in spec so I didn’t adjust them. So after that, about 15-20 hours of use just riding trails (no mud even up to the rims) And it just slung a rod through the case for no reason to my knowledge. I was riding solo (185 lbs) on a hard packed flat trail in high gear going slow, about 20mph, so RPMs were low, and it just slung it.

I pulled the engine out to disassemble and see what was salvageable and which route to go with the atv. So the crankcase was destroyed. Holes broke through from the base of cylinder down to the bottom side by the half of the rod attached to the crank. Well the crank has good bearings, and the rod is in good spec on the crank, no play at all and spins smoothly. The cylinder itself was in nice shape except the bottom lip the rod smashed into. The piston was also in good shape other than a deep scratch that came from the cylinder damage. And the rod attached to the wrist pin feels nice and as it should. The timing chain was tight. I couldn’t check timing because it wouldn’t turn as the rod on the crank was wedged. The intake valve got bent just slightly from the piston as it broke free, but the exhaust is fine, and it was so light it didn’t even dent the piston. The oil lines to the engine seem clear to me. When I took them off the engine oil came out of both of them no problem. The oil pump gears look normal. I’ve been running 10w40 synthetic in it since new. I’m in FL so it doesn’t get cold to bother it. And it broke during warm weather anyways.

Sooo… Why did the rod break? There’s usually a reason, but I can’t find one at all other than it got tired of doing it’s job.

Has anybody found a cross from NAPA or somewhere for this boot. I know on older models a Ford Escort or some Dodge Mini Vans were perfect replacements. Tore one up this weekend and would just like to go to the parts store instead of the stealer or Fleabay.

Thanks
Ronnie