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Discussion Starter #21
@latebird any thoughts or suggestions? I did try lowering the needle but at raised the idle quite a bit. Couldn't seem to get it to lower. And would back fire.


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Ok - I watched the vids - it appears to be lean on fuel under acceleration - idle sounds pretty good and they typically will never idle more than a minute or two

I just wondered how it might accelerate if you operated the 'choke' while trying to accelerate? If it does better, then obviously it need a richer mixture or higher compression to perform as expected. Try covering the air inlet of the air box with two layers of shop towel and see what effect restricting the air flow has. Maybe 3 or four layers will be requires to effect a change. If the experiment is positive, increase the size of the main jet about 4 sizes and see what effect that has.
 

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Discussion Starter #23
Ok - I watched the vids - it appears to be lean on fuel under acceleration - idle sounds pretty good and they typically will never idle more than a minute or two

I just wondered how it might accelerate if you operated the 'choke' while trying to accelerate? If it does better, then obviously it need a richer mixture or higher compression to perform as expected. Try covering the air inlet of the air box with two layers of shop towel and see what effect restricting the air flow has. Maybe 3 or four layers will be requires to effect a change. If the experiment is positive, increase the size of the main jet about 4 sizes and see what effect that has.
I tested compression and could only get a max of 62 psi. From what I can find I need around 100-115 psi. Would low compression give the same results?

I tried the China carb out and it made no difference. I swapped the original needle and jet in to see if that will change anything but haven't tried it yet. I believe that the original jet is larger then what came in the rebuild kit. I can see any markings on the original jet. I'll try the shop towels and see if it changes anything.

I know without seeing the cylinder wall to determine whether it's good still or needs to be machined or replaced it's hard to have a yes/no answer, is it worth just getting a top end rebuild kit?


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Discussion Starter #24
New problem. Fired it up. No choke, idle is really high. Shut it off. Started it again, idle still high, with 5 seconds started idling up. Shut it off. Backed the throttle stop screw out 4-5 turns and have the pilot air screw at a half turn out. Seemed to slow the idle down slightly. Visually inspection of the throttle and slide seem to move freely although when I give it throttle it acts like it's hanging.

I did initially try with 2 shop towels over the air box and it would bog down.


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Discussion Starter #26
I replaced the pilot jet with the original. Went to start it and broke the pull rope. Picking new rope up tomorrow.

I'll give that a shot


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Discussion Starter #27
Just had a thought, not sure if it would change anything or not. When I was first going through the quad I had noticed that the reverse override wires were cut and tied together. I hooked them back up to the override switch. Both wires are black. After some reading on trouble shooting the switch or Rev limiter could be a cause of some symptoms. I cut them and tied them back together.

Could that have a affect with it idling so high? I won't be able to disconnect them until tomorrow to try.


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Air in a new line is common and it won't hurt anything - fuel will flow right past the bubble and over a long period of time it will purge from the line. Similarly, air in a fuel filter will not affect the flow or function.
What about air in an old line? Is that an issue?
 

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What about air in an old line? Is that an issue?
Nope - if the line and filter were opaque you wouldn't be able to see any air and it would run just fine - fuel line routing is more critical on gravity feed machines than those with fuel pumps, but air can stay trapped in the line for years and never affect operation, but I have had customers insist on purging the air out of the lines. I charge $120 per hour to get rid of the air and it has never improved the performance the performance of any utility vehicle that I have worked on.

Now a high performance drag race fuel system is a bit more critical, so not all fuel systems are created equal and most fuel injection systems will self purge, but air in fuel injection can cause erratic performance.
 

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Discussion Starter #30
Try running with the top off the air box and the filter out
So I replaced the pilot jet with the original. Replaced the pull rope and now it only starts with the choke and won't idle for more than a second. As long as a give it some throttle it will run. It sounds like a need to adjust the throttle cable at the carb but not sure if that correlates to only starting with the choke on


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Discussion Starter #31
FINALLY it runs. Pulled the carb back out to give everything a once over. Pulled the pilot jet out and couldn't see through it. Cleaned it again put everything back together. First pull, no choke, fired right up. Idles pretty good, could be adjusted a little, doesn't bog at all. Drove it for about 5 minutes. No issues. Smokes a little. Might need new rings at some point. Just got to clean it up and possibly replace the brakes. Definitely need at least adjusting.


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CONGRATULATIONS!

And don't feel bad about not getting the carb on the first try. I just did a carb on a Kymco scooter - replacement was over $100 - I cleaned it carefully in my heated sonic cleaner with the $100 a gallon cleaning solution - it looked like new as I put it together and I had verified all the passages were open - it would not accelerate above 2000 rpm when I tried to ride it, but it would rev to the moon with the rear wheel off the ground - cleaned it a second time and the scooter runs like new again - my guess is although all the passages were open, some grunge remained and the passage was not fully open, but it is now. Perseverance prevails!
 

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Discussion Starter #33
CONGRATULATIONS!

And don't feel bad about not getting the carb on the first try. I just did a carb on a Kymco scooter - replacement was over $100 - I cleaned it carefully in my heated sonic cleaner with the $100 a gallon cleaning solution - it looked like new as I put it together and I had verified all the passages were open - it would not accelerate above 2000 rpm when I tried to ride it, but it would rev to the moon with the rear wheel off the ground - cleaned it a second time and the scooter runs like new again - my guess is although all the passages were open, some grunge remained and the passage was not fully open, but it is now. Perseverance prevails!
Thank you for your time and help. I'm guessing the carb rebuild kit was jetted wrong for the carb to function properly. The jet, pilot jet and needle are all original. I don't think I cleaned the pilot jet from the used carb. And when I installed it, it was letting very little fuel through.

Definitely glad it's running. My father in law also has a 2001 trail blazer 250 I may try and get running. At least the cables are moving on that one.


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Discussion Starter #34
Had it out for a couple of hours on and off over the weekend. No problems with it at all other than the brakes. As long as you don't need to stop it's good. I had them adjusted all the way up and didn't seem to change much. Took the "drums" off today and cleaned the pads and drums off. I'd say there is roughly 3/16" of pad left. Everything seems to function properly. Tomorrow I'll scuff the drums and pads up. They don't appear to be glazed over at all, but figured I'd see if it helps. I'll see if I can get anymore adjustment out of them.


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