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Testing for Spark on M8 touring

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  #41  
Old 01-13-2024, 11:58 AM
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For checking spark, pull a plug wire and stick a screwdriver in the boot and hold it so the shaft is near a fin or any metal on the engine
 
  #42  
Old 01-13-2024, 12:24 PM
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Originally Posted by EZ_Glide
This was checked on a 20 degree F engine, first test i did on front and rear cylinders had the acr sensors connected I thought they were not and got that 130/135 or so psi on rear and front. Disconnected and got same reading on rear of 130? They are within range according to service manual (within 10% and with acr connected above 110 minimum?) Just weird it's the same with or without that connected
That's not what is keeping it from firing..

Warmed up, it probably will read better and within 10 is great.

You said you checked resistance on crank sensor. I have a value of a good one but never seen it in a book. Takes a good meter to read that low.

It's an AC producing item. Set you meter to AC and crank motor and see what you get .

I post a value here shortly.

 

Last edited by Jackie Paper; 01-13-2024 at 12:36 PM.
  #43  
Old 01-13-2024, 01:00 PM
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@Jackie Paper forgot to recheck the crank sensor for voltage when trying to start til you mentioned it. Will try that in a bit as well and see what voltage I get. Should I try more oil as planned and check compression again?
@paulmedford it really isn't firing at all or want to from what I can tell. Also tested with that inline ignition tester with nothing... I squirted started fluid in spark plug hole, redid all connections quick and tried to crank it with no boom. It really cranks it well but it just doesn't want to get a spark or both spark and fuel.
if this compression should be enough to make it fire, I'll see if I'm getting 12v to ignition coil like mentioned before my other issues. Ha.
 
  #44  
Old 01-13-2024, 01:36 PM
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the red with green wire supplies Both the ignition coil and the injectors, ensure there is 12v. I think that's good enough compression to at least attempt to start. unless your cam timing off. With my build it was hesitant to start but the compression was low due to the fuelling hydraulic lifters, put back in the originals and compassion went back up. Even with the low compression the bike was firing, also I did put oil in and it raised the compassion to start the bike. ( lots of smoke lol), So try the oil and see.
 
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  #45  
Old 01-13-2024, 01:38 PM
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Originally Posted by Jackie Paper
That's not what is keeping it from firing..

Warmed up, it probably will read better and within 10 is great.

You said you checked resistance on crank sensor. I have a value of a good one but never seen it in a book. Takes a good meter to read that low.

It's an AC producing item. Set you meter to AC and crank motor and see what you get .

I post a value here shortly.
This is exactly how I check the crank sensor, by looking for a small ac voltage
 
  #46  
Old 01-13-2024, 02:01 PM
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CKP (Crank sensor) needs to read 1 AC volt minimum. It also should set a code if it's not working.

Resistance is 1 megohm which is hard to read for most meters
 

Last edited by Jackie Paper; 01-13-2024 at 02:25 PM.
  #47  
Old 01-13-2024, 02:15 PM
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@paulmedford unless I really messed up, my cam timing should be good. I really took care to match up all timing marks on the cam/crank pinion sprockets and the balancers to flywheel marks. I have the s&s lifters and quickee pushrods. Could the pushrods not being adjusted correctly mess with it? I still have yet to go back out to test but grabbing oil when I run errands here. I put in 5 quarts from a completely drained engine and oil pan and thought I saw somewhere an empty engine is like 5.3 quarts to fill then 4.5 for changes? Service manual wasn't specific about an empty amount.
 
  #48  
Old 01-13-2024, 03:21 PM
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the oil I thought you were talking about is putting about 5 mls of oil in the plug hole to raise compression. If you didn't adjust your pushrods properly the compression can be low like that yes.
 
  #49  
Old 01-13-2024, 04:02 PM
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The correct oil level is half way between full and add on a cold engine, any more will put extra oil mist out the breathers, but that's not the problem right now

Go through the pushrod adjustment , the compression should be up in the 200 range





 
  #50  
Old 01-13-2024, 04:18 PM
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Originally Posted by Schex
The correct oil level is half way between full and add on a cold engine, any more will put extra oil mist out the breathers, but that's not the problem right now

Go through the pushrod adjustment , the compression should be up in the 200 range
100% agree
 


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