Author Topic: How to adjust the air gap on the 79 Invader 340 flywheel  (Read 287 times)

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Vince Conerty Jr.

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How to adjust the air gap on the 79 Invader 340 flywheel
« on: March 23, 2019, 01:24:41 PM »
             What is the proper procedure to adjust the air gap on the 79 Invader 340 flywheel.  When I turn the engine over by hand I can feel and hear a coil rubbing the flywheel. My service manual does not show how to do this.  Thank You for any help. 

Interceptor398

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Re: How to adjust the air gap on the 79 Invader 340 flywheel
« Reply #1 on: March 23, 2019, 07:32:35 PM »
Welcome to the site!!   You will need to pull the flywheel and verify what is rubbing and are they the correct parts.  What is the history of the sled?

Vince Conerty Jr.

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Re: How to adjust the air gap on the 79 Invader 340 flywheel
« Reply #2 on: March 23, 2019, 11:01:54 PM »
           I got the Pulser and Trigger coil set from Manufacturers Supply , and the Lighting coil.  They look exactly like the ones I took out.  In the service manual It talks about improper air gap can affect spark. I have had problems with the ignition.  CDI box , Pulser and trigger coil. I have replaced these items as well as the ignition switch, cleaned and checked all the grounds in the system. Also replaced the External coil. Sled starts up but won't rev up now it just bogs. I have checked the wiring diagram and verified that things are wired correctly .   Fuel system has been gone through new fuel lines , also new line in tank plus the filter. Fuel pump rebuilt.  Carburetors cleaned and verified it has the correct jets. Needle clip is in the 3rd notch down from the top as the manual says is the standard setting. But I can see that the clip at one time was in the 2nd notch down from the top at one time. Vent line on the fuel tank is also OK. Engine was service New gaskets and crank seals. When I had the flywheel off I could see the flywheel had rubbed on the Pulser and trigger coil. The sled has 1,320 miles on it.
« Last Edit: March 24, 2019, 12:21:18 AM by Vince Conerty Jr. »

mswyka

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Re: How to adjust the air gap on the 79 Invader 340 flywheel
« Reply #3 on: March 24, 2019, 01:05:55 PM »
Sounds like  there might be a few things going  on.

I read that the jets are the correct size, but I didn't see that they were changed.   It is pretty easy for the 340 to be boggy and would recommend new jets to remove them from consideration as the problem.

On our last outing I had one of my fuel needles stuck open and the sled was pretty boggy taking quite a bit of work to get it going.  When I get it back from the camp it will get new fuel needles.  Although if the fuel needle sticks in the open position you will likely also see fuel leaking out of  the vent.

Aftermarket coils sometimes won't fit quite right under the flywheel.  But double check the flywheel part number to make sure that you have the correct flywheel on that engine.
Intruders:  1978, 1979 X2, 1980, 1981 Custom
Invaders:  1979 340, 1980 440, 1980 440 TOC Custom
Projects:  1981 Invader 440, 1979 Invader 340, 1980 Invader 340, 1979 Intruder 440, 1982 Intruder 440, 1980 Drifter 340 F/C, 1972 Panther 303 ...

Lloyd (ljm)

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Re: How to adjust the air gap on the 79 Invader 340 flywheel
« Reply #4 on: March 25, 2019, 11:40:10 PM »

 Did it rub with the original coils?

 Have you pulled the flywheel since you heard the rub noise? I am curious about what is rubbing.

 I doubt there is much adjustment in the air gap.
77 SST
78 Intruder
79 340 Invader
80 440 Invader
80 Drifter (bought new)
80 LTD 4/6    X2

Several Deeres