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3rd Gen Pulse gen coil resistance. HELP


VFRedneck

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Not sure if this is the right topic, but I bought new pulse gen coils and went to test them according to the manual, and apparently they test bad. I was hoping anyone with a running bike could take a minute and do me a favor by measuring the resistance on their 4 pin plug? Manual says to "measure the resistance between white/yellow-yellow and yellow-white/blue terminals." the resistance should be between 200-400 ohms, but both my old and new one are reading 300 on the first, and if im measuring right, no continuity on the second set. my problem is it appears that the second set is one wire from each coil, and there doesn't seem like there should be any continuity anyways. hopefully this made sense, and also should the coils be gapped from the pickups a specific amount?

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Hi VFRedneck.

Don't have a 3rd gen. But had a look at the Service Manual for the VFR750. The two Pulse Generator wires are Yellow (common) and White/Yellow, and White/Blue. The ohms reading for both Pulse Generators is stated to be from 450 to 550 ohms in one part of the manual then it states 200 - 400ohms at 20degC in another part, bit confusing!

 

The bottom line is, with your meter probe on the Yellow (common) and the other on either the White/Yellow or the White/Blue you should see near enough the same resistance for each coil. You MUST get a reading for both coils.

 

Not sure about the pickup gaps, there is no gap setup in the manual, would assume by simply fitting the Pulse Generators they would be correctly preset in the right position.

Hope this helps.

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On 7/19/2018 at 11:03 PM, Grum said:

Hi VFRedneck.

Don't have a 3rd gen. But had a look at the Service Manual for the VFR750. The two Pulse Generator wires are Yellow (common) and White/Yellow, and White/Blue. The ohms reading for both Pulse Generators is stated to be from 450 to 550 ohms in one part of the manual then it states 200 - 400ohms at 20degC in another part, bit confusing!

 

The bottom line is, with your meter probe on the Yellow (common) and the other on either the White/Yellow or the White/Blue you should see near enough the same resistance for each coil. You MUST get a reading for both coils.

 

Not sure about the pickup gaps, there is no gap setup in the manual, would assume by simply fitting the Pulse Generators they would be correctly preset in the right position.

Hope this helps.

So I finally found out that that was for two different locations. 450-550 for the plug that goes to the icm, and 200-400 for the plug that plugs into the harness. The coils are good, and I believe the culprit is an issue in wiring, causing there to not be enough resistance at the icm plug. I’m not sure what could be causing it, but the resistance is nearly identical to the reading I get from the pulse gen plug. 

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5 hours ago, VFRedneck said:

So I finally found out that that was for two different locations. 450-550 for the plug that goes to the icm, and 200-400 for the plug that plugs into the harness. The coils are good, and I believe the culprit is an issue in wiring, causing there to not be enough resistance at the icm plug. I’m not sure what could be causing it, but the resistance is nearly identical to the reading I get from the pulse gen plug. 

So are you saying that if you pull off the plug at the ICM and measure resistance of the Yellow (common) to either the White/yellow or the White/blue you are not getting near equal resistance? This value should be virtually the same as measured at the two coils!

Cannot believe what you are saying that you should see 450-550 ohms at the ICM plug, and 200-400 ohms at the plug for the coils that just doesn't make sense.

Do a continuity check that each of the three wires from the ICM plug down to the plug for the coil is virtually zero ohms for each wire plug to plug. You can also easily check that each wire has no shorts to frame. The coils as well should have no shorts to frame. (Virtual infinite resistance)

If the coils measure ok, and the continuity of the wiring from the coils to the ICM are ok. Then your problem is elsewhere.

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On 7/23/2018 at 6:09 AM, Grum said:

So are you saying that if you pull off the plug at the ICM and measure resistance of the Yellow (common) to either the White/yellow or the White/blue you are not getting near equal resistance? This value should be virtually the same as measured at the two coils!

Cannot believe what you are saying that you should see 450-550 ohms at the ICM plug, and 200-400 ohms at the plug for the coils that just doesn't make sense.

Do a continuity check that each of the three wires from the ICM plug down to the plug for the coil is virtually zero ohms for each wire plug to plug. You can also easily check that each wire has no shorts to frame. The coils as well should have no shorts to frame. (Virtual infinite resistance)

If the coils measure ok, and the continuity of the wiring from the coils to the ICM are ok. Then your problem is elsewhere.

Sorry it took me so long to get back to you. Bike has been at the shop for a long time and right now the mechanic is saying that he thinks it’s something keeping the motor from turning fast enough to generate spark. He’s gone through all of the electricals and hasn’t found anything. Hopefully getting in touch soon to see what he’s discovered 

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6 hours ago, gll429 said:

if your bike isnt starting, tell him check to see if the starter clutch is cracked..note.. the rollers are place 90* wrong to hold them in place for the pic

starterclutch2_zpsworrcydn.jpg

 

It isn’t, the guy I got it from replaced it and after that discovered the no spark issue 

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6 hours ago, gll429 said:

if your bike isnt starting, tell him check to see if the starter clutch is cracked..note.. the rollers are place 90* wrong to hold them in place for the pic

starterclutch2_zpsworrcydn.jpg

 

That's a pretty big crack...

 

VFRedneck, about your mechanic.  Does he work on a lot of Japanese bikes?  The only moving part in the entire ignition system is the rotor on the end of the crankshaft, which has raised triggers that magnetically operate the two pulse generators, which then send signals to the spark unit, which in turn sends electricity to the coils, which then fire at the appropriate moment.  The system needs electricity to generate spark, not speed.  

 

 

Ciao,

 

JZH

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1 hour ago, VFRedneck said:

It isn’t, the guy I got it from replaced it and after that discovered the no spark issue 

 so this guy is randomly replacing stuff without checking them 1st ? get new mechanic.

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3 hours ago, gll429 said:

 so this guy is randomly replacing stuff without checking them 1st ? get new mechanic.

Nonono, the guy I got it from didn’t ride it for a while and went to start it and discovered the bad starter clutch. He replaced it and then discovered the no spark issue. That’s when I got it. The mechanic hasn’t found any electrical issues, and last I spoke to him he thought the engine wasn’t cranking fast enough to generate spark. 

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the number one flaw on the VFR.. ground wire!  aka green.. PM sent.. check your mail box.. bad ground can mess with spark even when everything is " working "

 

20180929_014041_zpsizdhxote.jpg

20180929_014846_zpswgculfax.jpg

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