can I use a gel battery in an '86 1VJ?

I don't see why not... If it has all the same characteristics you should be fine


Vando

I use a gel battery with no problem at all

By the way, what's the difference between the normal acid batteries and the gel batteries?


Vando

I think the difference is you don't have to top up a gell battery. you don't have to carry any distilled water, less weight.

Exactly.

Less weight, any position is acceptable (even upside-down), sealed fluids with no leak possibility, and high power output.

Don't mix up things. Most commonly you will find flooded cell or AGM batteries on bikes. The AGM is quite similar to a flooded cell besides the fact that it's maintenance free as mentioned before. And yes, you can lay it flat or fit in whatever position is best suited. They are slightly more expensive than an equivalent flooded cell battery but pay back with much longer lifetime, no leakage of acid if tipped over and high vibration and shock resistance.(assuming proper care = no deep cycling). You can get a same size replacement for a number of flooded cell batteries for example YTX14LAH for YB14.
A same capacity AGM battery is not considerably lighter than the equivalent flooded cell battery.

Gel is a totally different story and they are not commonly found on bikes (besides a few).
They require more sophisticated charging circuits as they are sensitive to high charging currents. Their advantages are less sensitivity to deep cycling and a long lifetime. Disadvantage: Very expensive, very sensitive to standard (non constant current) battery chargers and jump starting with jumpers connected directly to battery terminals.