1979 Pantera engine woes - ArcticChat.com - Arctic Cat Forum

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post #1 of 5 Old 06-13-2012, 07:18 PM Thread Starter
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1979 Pantera engine woes

By all accounts, I have a 1979 Pantera 500cc motor. It's now in a golf cart, with the fuel tank above the motor and a Mikuni pulse pump feeding it. I'm not a 2 stroke pro, so I could really use some help with this issue.
  • The good:
    The motor starts immediately and idles very well. If I get in and go immediately after starting it, it goes like a champ. If I had to guess, I'd say it accelerates slower than expected, but it goes and goes pretty decent.

  • The bad:
    If it is left to idle for even a short while (less than a minute), there is no throttle response. You can hear the tone of the motor lower with the throttle wide open, but it doesn't rev a lot higher than idle, and it's inconsistent.

I cleaned the carb and it looks great. Everything moves freely and it is free of grime on the inside. I put a 4-7lb. fuel pump in place of the pulse pump to see if it wasn't getting enough fuel and that didn't change the behavior at all. I just ended up with fuel spitting out of the pulse pump nipple in the crank case and out of what I imagine is an overflow hole in the carb.

I don't know what a motor behaves like or sounds like when it's flooded, so I don't know if it's getting too much fuel or not enough. It has good compression, and there's definitely spark.

ANY help is appreciated. I'm at my wits end trying to figure it out.

Last edited by GregJ; 06-13-2012 at 07:29 PM.
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post #2 of 5 Old 06-14-2012, 07:21 PM
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Sled: 71 lynx 292, 74 lynx wankel, 84 el tigre
Greg, first off I would try to put the fuel pump back to stock but before you put it back on take it apart and look for holes in the diaphrams. Could you give some pics of the carb and the fuel pump or type and model numbers.
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post #3 of 5 Old 06-14-2012, 07:25 PM Thread Starter
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I didn't get the stock fuel pump with the motor unfortunately. I now actually think I could get away without running one, but it is now working with the aftermarket Mikuni pulse pump I bought.

I took the carb apart for the 4th time last night as it just felt like a fuel problem, and low and behold cleaning out the jet with wire revealed the jet was much larger than I originally thought, and was just gummed up.

It seems to be running fine now, but I keep eating belts because the motor is offset about 1/4". Once I get the motor shifted back a bit I'll take another video.
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post #4 of 5 Old 06-15-2012, 04:56 AM
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Sled: 68 Panther,70 Puma 744, 91 EXT 530.
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how is it jetted? does it have the stock jetting meant to run at zero to twenty degrees? she wont run when it 70 to 90 temps with the "winter" jets. make sense?

I will give up my vintage sled when they pry my frozen dead thumb from the throttle......WOT of course!
68 P-17-H
70 Puma MOD 740 Sachs
71 292 Lynx
72 440 Panther
78 Tiger 5000
91 EXT 530
1966 Cub 102C
1968 cub 104C
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post #5 of 5 Old 06-15-2012, 01:35 PM
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Pretty sure you don't need that fuel pump cause you have the fuel tank higher then the carb. Thus it's gravity fed. Could use it or remove it and cap off the vacuum line coming from the base.

I too agree you might have to swap jets. Summer temps = smaller jets?? i'm not sure.

1998 ZR500 Carb
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