One spark plug cap creates weak spark...Why?

[Vloukole]

My GS1000G has 3 of the 4 plug caps stock and the other 1 is a NGK cap. This NGK cap creates a very weak spark. I switched the caps around to check if it is something else but the weak spark stays with the NGK cap.

The part number is 43010 and 10k ohms is written on it.
Why does it create that weak spark??

 

[Nessism]

I'm not familiar with that particular cap, but Suzuki calls for 5k resistance on the caps.

 

[Vloukole]

Do you think it will solve the problem? Going with 5k ohm cap?

 

[JTGS850GL]

I use NGK 5K caps and have never seen a weak spark issue. If the problem follows the cap then you've discovered the source of your problem.

 

[Vloukole]

Great thanks

 

[Joe Garfield]

Z1Enterprises has a great deal on spark plug caps (resistor covers) and they have the right ones for our bikes. I just got 4 of them, they were $3.06/ea. If you look on BikeCliff's pages he has tutorial about replacing them, and he gives the P/N's that he uses. I got (2) XB05F and (2) VB05F.

The standard setup for these bikes uses 5,000 ohm spark plug resistors as mentioned above. The 10K ohm resistor is double that, so there is an extra 5,000 ohms of resistance between the the ignition coil and the spark plug which would result in a significant loss in voltage at the spark plug.

For reference, that is equivalent to 2,000 feet of the 14-ga wire used to wire a house, or roughly 1,000 feet of the wire used throughout most of the bike.

Here is a pic of the parts that are inside the cap:

 

[Vloukole]

Thanks Joe. That's what I wanted to know. I will go and get them. Are those part numbers only for a certain brand of cap or for any brand like NGK , Denso aswell?

 

[Joe Garfield]

Those are NGK part numbers. I briefly looked for other brands or options but did not find much, and you can't go wrong with NGK anyway. Those part numbers are very close to what is originally on the bike. The long one has a slightly sharper angle but it shouldn't matter much. The short one has more length after the bend but it looks/fits good. I think they are the closes you will find without going with Suzuki.