How do I identify a bad ignition coil?

[RossKean]

Advice taken!

 

I guess there is a little more incentive to remove a possible point of failure for a two cylinder Roadstar than the four cylinder Venture - The Roadie doesn't run on one cylinder but the Venture will do OK on three. As you mentioned, it seems like a good idea to thoroughly check out the caps (and the resistor) before deciding that a coil is in need of replacement!

 

Ross

[Zane]

Here is one source for caps. I have not personally used any after market caps on a Royal Star, but it seems to me that the SD05F cap would be the right one. Actually, an SD10F would be the proper one (10K resistor instead of 5K), but I can't find a source for that yet; it probably does not exist.

http://www.z1enterprises.com/SearchResult.aspx?All=True&KeyWords=ngk%20cap

Here is another source - looks like the part number has been updated to SD05FP:

http://www.ngk.com/results_cross.asp?pid=sd05fp&x=58&y=13

 

BTW - I found that NGK makes a wire splicer specifically intended to replace wires on coils like ours - you cut the old wire an inch or two past the coil and splice on the new wire. It is shown on their web site under performance accessories.

Goose

 

Goose, I found a source for those wire splicers!

 

http://www.parkeryamaha.com/ngksparkplugwiresplice.aspx

[V7Goose]

Goose, I found a source for those wire splicers!

 

http://www.parkeryamaha.com/ngksparkplugwiresplice.aspx

Excellent info - Thanx!

Goose

[Seaking]

Goose, I found a source for those wire splicers!

 

http://www.parkeryamaha.com/ngksparkplugwiresplice.aspx

 

They look a lot like the connectors on the HID light systems installed on the bike.. Cool.

[sleadhed]

well you could start the bike up , let it run for a few minutes. then do the old way of touchee feelee on each exchaust pipe next to the head. your finger is a great indicator of weather or not the coil is sending juice to the spark piug. don't ask me how i know this. but kbay sure got a big chuckle, watching me

don c.

This would work well for coils that are dead through all RPM ranges. However It's been my experience that our coils tend to fail under high load demand ie 4th and 5th gear Goose has been looking in to this for quite some time. I think he is on to our common failure. I replaced all 4 of mine 1 under warranty and 3 I replaced myself 2 of the 3 I replaced had crrosion beginning to form. I sure would have liked to seen the warranty coil cap since it failed at around 600 miles and the dealer did not replace it untill the fifth visit and 9000 miles.

[TEW47]

On my old'97 RSTD all four caps went out over a period of time. Payed for one because it was backfireing real bad and it looked like fire comming out of the right exhaust. The others I replaced myself. Worked fine after that.

 

tew47

[Beau-Kat]

Now I'm not positive as far as the compatability of the 1st gen caps to the 2nd gen, but I would hazard a calculated guess that the caps would be the same. The only issues I see would be the wire size (which is 7mm on the 1st gens) and the resistor inside the caps being the same. Perhaps Goose has some insight on this.

 

So what plug wire size is on the 2nd gen?

 

I see the link to the splicers. They say they only work on 7mm size.

[Beau-Kat]

Bump

[Beau-Kat]

So what plug wire size is on the 2nd gen?

 

I see the link to the splicers. They say they only work on 7mm size.

 

 

(BUMP)

[SaltyDawg]

Well my RSV was missing on both rear cylinders Saturday. It was hitting intermittently through most of the power range. I went out this morning to look at one of the plug caps.

 

When I checked resistance it was 9.6K. I then opened it up and emptied the contents onto the table. I had the brass plug, the resistor, the spring with corrosion, and what appeared to be clumps of black powder. I am assuming this was whats left of the brass disk because there was not one in it. I cleaned the spring and the end of the brass plug, put it back together (without the brass disk) and my resistance is now 290K.

 

Think I may have found my problem.

 

Gonna try and get new caps and see where I am.

[gibvel]

Well my RSV was missing on both rear cylinders Saturday. It was hitting intermittently through most of the power range. I went out this morning to look at one of the plug caps.

 

When I checked resistance it was 9.6K. I then opened it up and emptied the contents onto the table. I had the brass plug, the resistor, the spring with corrosion, and what appeared to be clumps of black powder. I am assuming this was whats left of the brass disk because there was not one in it. I cleaned the spring and the end of the brass plug, put it back together (without the brass disk) and my resistance is now 290K.

 

Think I may have found my problem.

 

Gonna try and get new caps and see where I am.

 

Yeah, my brass disks were black and most of them were in, at least, 3 pieces. I fashioned some new ones from the heads of some round head screws with a bit of belt sanding and filing.

 

Just went and looked on the Part Shark website and, apparently, you can order just the OEM plug caps. Problem is they're like $25.19 each. Goose posted links to the NGK plug caps, but after looking at the specs. on them I decided that they won't fit on ours. I don't recall why but I think the length was the issue.

 

If someone has changed to the NGK plug caps, that Goose suggested, please let us know if they worked out or if you had some problems with fitment.

Edited October 11, 2010 by gibvel

[jointventure]

Yeah, my brass disks were black and most of them were in, at least, 3 pieces. I fashioned some new ones from the heads of some round head screws with a bit of belt sanding and filing.

 

Just went and looked on the Part Shark website and, apparently, you can order just the OEM plug caps. Problem is they're like $25.19 each. Goose posted links to the NGK plug caps, but after looking at the specs. on them I decided that they won't fit on ours. I don't recall why but I think the length was the issue.

 

If someone has changed to the NGK plug caps, that Goose suggested, please let us know if they worked out or if you had some problems with fitment.

 

 

It seems that a very common problem with seemingly dead cylinders and misfires may have been solved on this thread. I'd would also like to know if anyone has had these NGK caps work.