My son needs to replace the battery in his XJ750RK. He went to Sears and got a Diehard, but it doesn't have the sensor. I told him he needs to take the battery back and get the correct one. If I remember correctly, the new battery should come with a new sensor....... Is that correct? Or does the battery just need the screw in caps so the old sensor will screw into the proper one?

Some of the Yuasa battery models come with a sensor. Yuasa has been discontinuing a lot of those, though.

I've been using off-the-shelf lead acid batteries, like Diehards and Exides, and drilling and/or tapping mounting holes for the sensor as needed.

Can you explain in a little more detail?

Most aftermarket replacement batteries for the Yamaha models do not come with a sensor nor with provision (threaded cap holes) for the original screw-in sensor. Yuasa (the original battery supplier) offers their replacement batteries for this model both in a sensor and non-sensor versions. The non-sensor versions are less expensive, and although their sensor-version battery comes with the sensor, it is a different sensor from the original sensor.


Which brings up an important point.........what SQL is referring to is that you can use an original sensor on an aftermarket battery if you use a proper-sized bolt to "cut" threads in the aftermarket battery cap hole (so that it will have threads that the original screw-in sensor can now thread into); but, be aware that the original sensor probe tip may be "too deep" for the type of battery you purchase; the original sensor tip is rather deep and if it contacts the plates in the aftermarket battery, well, that's very definitely not a good thing.

So you may end up having to modify (cut off) some length of the probe tip of the original sensor, or use some type of rubber or plastic "shims" to space up the original sensor so that the sensor probe tip does not contact the plates within the replacement battery (as well as having to "thread" the cap hole of the replacement battery to accept the original screw-in sensor). We carry such shims (and the correct thread-cutting bolt) for use in modifying replacement batteries (as well as the correct original sensor, and original and replacement batteries of various types).


And, of course, the "permanently sealed" maintenance-free replacement batteries may not even have removable/replacable port caps, in which case an original sensor cannot be adapted to it in any manner.

u can use a bolt to thread the threads into the 2 ports you need for yur sensor. ask chacal about the thread size cause he knows it and i forgot it. he is the parts guru here and can be found in the forums.

What is the proper bolt size and what is the procedure? Must a hole be drilled in the new battery or can one of the existing holes be threaded? What is the cost of the shims?