Author Topic: 4/6 Running Problems  (Read 19326 times)

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mswyka

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Re: 4/6 Running Problems
« Reply #15 on: December 26, 2012, 10:32:48 AM »
Bob, back  out to the sled to check the primers - no bubbles.  Sealed the primers and no change in operation.  I realize that I am probably missing something obvious, but it is still the same.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

Invader440

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Re: 4/6 Running Problems
« Reply #16 on: December 26, 2012, 12:08:58 PM »
If I can keep it up around 3,500 she will stay running. 
Idle set too low?

Checkmarks

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Re: 4/6 Running Problems
« Reply #17 on: December 26, 2012, 12:15:21 PM »
Oil fouled plug?

mswyka

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Re: 4/6 Running Problems
« Reply #18 on: December 26, 2012, 01:20:32 PM »
If I read the manual correctly, standard idle setting is 2,500 - Normally we set the sleds up to idle around 2,800 or 3,000.

Mark, I will check the plugs.  It has 4 Denso Iridium.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

jimvw57

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Re: 4/6 Running Problems
« Reply #19 on: December 26, 2012, 02:23:21 PM »
4/6 has a higher idle (3,000), as long as idle is set below the clutch engagement point (4100 rpm), you'd be fine.

mswyka

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Re: 4/6 Running Problems
« Reply #20 on: December 26, 2012, 03:46:25 PM »
Snowing now, it is going to have to wait until tomorrow.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

Invader440

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Re: 4/6 Running Problems
« Reply #21 on: December 26, 2012, 07:20:32 PM »
2500 sounds more like for a 78 Intruder.  Yea, I'd bump my idle up more around 3200-3500.  Like Jim said, as long as you are below the clutch engagement you are fine.
« Last Edit: December 26, 2012, 07:23:26 PM by Invader440 »

Interceptor398

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Re: 4/6 Running Problems
« Reply #22 on: December 27, 2012, 07:34:06 AM »
2500 is the correct idle for a 4/6

mswyka

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Re: 4/6 Running Problems
« Reply #23 on: January 01, 2013, 08:01:00 AM »
I think I am about ready to give up on this 4/6 and put it back in the barn or post it to craigslist.  There was a time that I thought that I could figure out every problem - and when I couldn't there was always someone here on the forum who would offer some sage advice.  But this one just has be bumfuzzled.  No matter what I do I can't seem to keep it running for more than 10 to 20 seconds below 3,500 RPM.  I had convinced myself that it was something obvious, but no matter what I check nothing has made itself obvious.

While I can't rule out carburation completely, the carbs have been checked, re-checked, cleaned and checked again.  Crank seals have been replaced. 

It starts easy, and runs like a banshee above 3,500.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

bpmailman

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Re: 4/6 Running Problems
« Reply #24 on: January 01, 2013, 08:13:14 AM »
Change the tach Mark.  BTW mine wont run very long below 3000. ???

mswyka

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Re: 4/6 Running Problems
« Reply #25 on: January 01, 2013, 08:16:38 AM »
Mailman, good to hear from you.  I would be OK with the slow die off that I get from the other Invaders, but this one Idles level for 10 to 20 seconds and then just drops dead rapidly, not slowly like the other Invaders.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

jimvw57

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Re: 4/6 Running Problems
« Reply #26 on: January 01, 2013, 09:00:15 AM »
Clutch kicks in at 4,100 so set the idle higher

Interceptor398

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Re: 4/6 Running Problems
« Reply #27 on: January 01, 2013, 09:35:41 AM »
Have you tried a leak down test??

mswyka

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Re: 4/6 Running Problems
« Reply #28 on: January 01, 2013, 11:09:06 AM »
Leak down test?  No I have not.  Not sure I have equipment for that since my compression gauge is a rubber stopper type rather than a screw in.  I will see if I can find one.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

jimvw57

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Re: 4/6 Running Problems
« Reply #29 on: January 01, 2013, 01:35:56 PM »
Yeah, I know the feeling. when I was fighting with my 4/6, it ended up being flakey ignition coils. Put a new pair on and it took right off. I would have sworn it was carburation, went through 4 or 5 sets of carbs.

yours still sounds like pilot jets..


« Last Edit: January 01, 2013, 01:39:20 PM by jimvw57 »