Spark plugs for Conquest

[beagle man]

I have a 2002 conquest with the FD 620 Kawasaki V-twin, sounds simple. The plugs that are in it are NGKBPR4es. I got Champion RN14YC (405) for replacements because that's what I could find. Now comes the confusion. The manual says Kawasaki changed the heads on the FD620 after VIN.# CB17---( I'm guessing the last 6 or 7 characters in the VIN. #) and the new plugs will damage the heads because they are too long. Does anyone else have this conflict the? Cross reference tables say their a match however the Champions do appear to be a little longer.

[plott hound]

if they are longer,dont put them.get the proper ngk plugs.

[Deedeelin1]

B

[ARGOJIM]

If your champions are slightly (like 1/32) longer no problem if they came with compression seals ( metal rings), but I would still run the NGK's as they are correct and a much better plug. If your plugs did not foul, you could order new ones and continue to run them until a new proper set comes in.
The earlier machines plugs were half as long and piston contact is possible with newer bpr4es in them.

[plott hound]

my '96 conquest had that happen.previous owner put the wrong plugs in and marked the piston top and heads pretty bad.when I bought it the head gasket was leaking coolant into the cylinder but I lucked out and salvaged the head with a little massage.

[Deedeelin1]

b

[beagle man]

The new NGK BPR4ES plugs are longer than the old ones? Good grief!!! I looked at several cross reference tables to check but I wonder how often they are up dated. Deedeelin1 I'm curious, If your not running NGK's what are you running, if you don't mind taking a look that would be great. I'm tempted to put in the new plugs and roll the engine over by hand,( key and plug wires off) to see if there is contact, maybe not a good idea,any contact will leave a mark and thats not good. 200 hundred miles round trip to Fairbanks from Delta jct.

[ARGOJIM]

The early kaw's ran bmp4a? (letters may be slightly off but the 4a is a shorter threaded plug like a champion cj8 and the j17lm)threads were half the legnth, if your engine had the bpr4es in it running ok you should be good. Rolling engine over is a good idea.

[Deedeelin1]

b

[msafi65]

Joe the difference between the short plugs and the long ones is about 3/8". The older ones take the short plug and it has just over 1/4" of total threads. To add fuel to the fire I like the champion plugs.

[Deedeelin1]

B

[Deedeelin1]

B

[beagle man]

Mark I think you may have answered my question about the plugs. The NGKs that where in the machine have about 3/4" threads so it must have the newer engine design with higher domed heads. I found 9 different plugs that cross reference with the RN14CY. I would think different heat ranges resistor and non-resistor and so on. The RN14CY is in the middle of the heat ranges from what I found out online. Cross reference numbers I found are N14YC,N16YC,RN16Y,XN14Y,N13Y,N16Y,RN14Y,RN16YC,XN1 6Y,and STK405 which is the same as the RN14YC plug.

[beagle man]

I don't know if this helps anyone but the date of manufacture on my engine is 08/2001.

[beagle man]

It now has the champion plugs and running smooth again, also synthetic oil, filter change, tranny oil, grease job, and new yellow top Optima battery Ouch. Oh and they put the battery post on the opposite side so the positive post is very near the radiator 1/2" to 3/4" clearance but I do have the rubber boot covering it and clamped down in the tray.