Smaller Battery / Airbox Mod

Well I'm just finishing up dialing in my 06 WR450 and I remember seeing a couple posts about aftermarket batteries. I use my bike 60% Desert 40% track so I have put some extra time into weight reduction and throttle response. After all the usual uncorking and weight removal I started looking at the closed up airbox and the heavy battery. My solution was a Power Sonic PS-1212. It is the same length as the stock battery but about a third the width. It fits well using the stock rubber battery strap and a few zip ties to prevent side to side motion with a little padding underneath for a nice tight fit. After installing the battery I then cut out two pieces of the battery box alongside the battery to increase the airflow as well as cut out the rear of the airbox that remains after the snorkel is removed. The end result..... saved three or four pounds up high in the chasis, I noticed a crisper throttle response (already jetted, quick-shot, full yosh exhaust, Iridium plug, etc), mabye a 5-7% improvement over what I already had. As far as starting the little battery is good for 5 seconds or so of turning time before it starts running out. It has worked every time once the bike is warm, but usually doesn't last for a cold start. I'm fine with kicking it and starter removal is next on the list, I'm just looking for a YZ cover to keep it clean. The only thing that gave me trouble was getting a good enough contact with the battery cables, once I handled that it worked fine. Here's a pic...Take it or leave it. Oh and the battery was $22.00, weighs 1.2lbs, and is rated at 1.2AH.

Here's the whole thing

do you find that the battery charges itself quickly when riding?

This looks like a worthwhile project if it can shave several pounds of high-up weight.

The battery runs up in a couple laps. I've never tested it specifically for charge up time, but I would guess no more than 10 minutes. Next time I ride I'll test it out and let you know.

damn and i just ordered a stock replacement for 56

I have a question, i'm not an electrical expert so sorry if its a stupid one :ride:

A regular automotive style battery has a pair of very heavy sturdy terminal which the vehicle leads are bolts to. Batteries like the one in the picture do not.... could cranking an engine over heat up the leads and/or terminals? Maybe even melt them? I'd guess there's a lot of amps being drawn through there when cranking :thumbsup:

I haven't had any problem with that yet. The smaller battery doesn't crank long enough to build up that kind of heat. It's good for one shot only, but for me the weight savings and extra air flow was worth it.

there sure is alot more air getting in there with that smaller battery forsure, I too am now interested.

I haven't had any problem with that yet. The smaller battery doesn't crank long enough to build up that kind of heat. It's good for one shot only, but for me the weight savings and extra air flow was worth it.

Cool. Just the cogs in my mind grinding over..... :thumbsup:

bringin up an old thread her but can you just take your battery completey out if you don't use the estart? Or does it need it for the on/off buton?

I have been wondering if the battery for the new KTM 450 is going to be lighter then ours. I am sure it would still have plenty of starting power.

Cutting out the air box always puzzles me, surely the air flow is restricted by the diameter of the carb intake, filter & jetting. There has to be a limit to the flow achieved when cutting out the air box.

Im sure there is a max point to make it worth wile. however stock always seems to be restricted........

Did you remove the radiator overflow tank? If so... where do you run the line from the radiator? Also, Where did you mount your on/off switch. I am in the process of making my WR into more of a YZ for some track time.

I ran the line down with all the other hoses from the carb. I mounted the on/off switch on my bar clamps. I had to modify it a bit to get it to fit but it looks good.

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