Author Topic: 78 intruder problems  (Read 3730 times)

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norm

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78 intruder problems
« on: June 11, 2020, 09:10:58 AM »
looking for help on intruder,checked compression 160 on each side, have great spark (new coil). have fuel, checked timing it is  perfect.
Even went as far as replacing old carbs with new ones. the thing will only pop a couple of times them die. Has anyone else had this problem.

DougKauer

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Re: 78 intruder problems
« Reply #1 on: June 11, 2020, 04:12:19 PM »
How long has it been sitting. check for mice
.

Interceptor398

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Re: 78 intruder problems
« Reply #2 on: June 11, 2020, 08:40:51 PM »
Welcome to the site!!  For me in the past "a couple pops and nothing" says badly flooded.

norm

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Re: 78 intruder problems
« Reply #3 on: June 11, 2020, 09:04:47 PM »
Awesome site and thanks for the reply. The sled showed no
Sign of mice. I thought the motor could be flooded but took
Plugs out took muffler off and let sit for week. Pulled motor
Today and found crank seal on PTO side cracked and missing small pieces. Could this possibly be the problem.

Interceptor398

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Re: 78 intruder problems
« Reply #4 on: June 12, 2020, 11:46:56 AM »
A great place to start with any motor this old is to replace the seals.  Many problems that are hard to pin point can be eliminated plus the chance of melting it down is greatly reduced.

mswyka

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Re: 78 intruder problems
« Reply #5 on: June 12, 2020, 04:47:32 PM »
Definitely replace the crank seals.  As a test, try to start with the exhaust off.  We have had many mouse nests in exhaust that have prevented running.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

norm

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Re: 78 intruder problems
« Reply #6 on: June 12, 2020, 09:46:15 PM »
I wondered about the plugged exhaust,  I could only get it to pop with muffler unhooked. I am going to install  new crank
Seals tomorrow along with total rebuild. Will keep you guy's
Posted how things turn out. Thanks again

mswyka

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Re: 78 intruder problems
« Reply #7 on: June 13, 2020, 04:02:44 PM »
I will also throw out one other of our recent blunders. 

Full rebuild on a 1980 Intruder.  All electronics tested before assembly.  Fuel pump tested before assembly.  Would only pop once or twice.  Finally pulled the engine out and found that the flywheel key was stuck to the inside of the flywheel.  It apparently slid out of the keyway when i was doing the final assembly.  Put it back together the right way and she fired right up and ran like a top.
Intruders:  1978, 1979, 1981 Custom (Pink)
Invaders:   1980 440
Projects:    1981 Invader 440

Boomologist

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Re: 78 intruder problems
« Reply #8 on: June 14, 2020, 03:08:39 AM »
After purchasing an Interceptor for a very low price I couldn't get any spark. Pulled flywheel and discovered that someone had laid the flywheel down where there was a lot of loose items and the magnets picked up quite a few small screws, nuts and one small socket. He apparently didn't look inside when he put it back together. Needless to say that all that junk going around killed the coils and knocked the magnets off the flywheel (on interceptors they are surface mounted).
Guess that's why I got it so cheap.

norm

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Re: 78 intruder problems
« Reply #9 on: June 14, 2020, 03:46:53 PM »
Well total rebuild, crank seals,piston and rings,new plugs
New coil, new carbs no mice and keyway on cank
Ok. T mark on flywheel lines up with case mark when mag side cylinder is at TDC. Could it be bad stator or CDI? Stator
Plate marking is at 3 o'clock . The Joy's of vintage sleds.



Interceptor398

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Re: 78 intruder problems
« Reply #10 on: June 15, 2020, 08:33:44 AM »
Will it fire if you put a bit of gas in the spark plug holes?

norm

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Re: 78 intruder problems
« Reply #11 on: June 15, 2020, 12:19:06 PM »
it will only pop a couple of times.

Interceptor398

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Re: 78 intruder problems
« Reply #12 on: June 15, 2020, 02:00:44 PM »
So it will fire makes me wonder if it a few delivery issue??  Are the fuel lines to the carbs full of gas or is there a good supply of air bubbles,  bubbles are not good? I have heard a coupe times of the kill switch causing problems.

norm

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Re: 78 intruder problems
« Reply #13 on: June 15, 2020, 04:09:51 PM »
Kill switch fine, but fuel lines are not full.
Failing or weak fuel pump?

norm

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Re: 78 intruder problems
« Reply #14 on: June 18, 2020, 06:14:20 AM »
Well after countless hours of hair pulling and busted knuckles. The beast awakens. Nothing better than bringing a 42 yr old sled back to life! Thanks to all for the help,
And thank you for the awesome site.