Battery

I tried the CBR600 battery in one of our '04 YFZ's, then later in an '06. Honestly, it didn't seem to work or last any better than the OEM batteries in our other YFZ's. Personaly, I think your money would be better spent on a battery tendor (like the Optimate) and keep the batteries fully charged when your not riding.

Even on our high compression motor, the stock batteries are working fine.

I have an 05' pretty sure it is the original battery and with a dune trip coming up having a brand new battery just makes me feel better going into it. I have just heard bits and pieces of people running different batteries than the OEM. The thing is just so cold blooded that it doesn't always want to fire up right away.

I agree with DADDIO on just buying a Tender for the meantime while you're not riding. I have a 13.5:1 compression motor that cranks over just fine with an OEM battery. Granted, I have had to replace it this last time I did my rebuild because when I removed it fro the bike I never put it on a tender.

You might want to check your valve clearences to make sure they're with in spec. This could possibly be your problem.

valve clearance could be the issue for being cold blooded because my 06 is bad but once i ride it for a few and it gets warm itll start right up everytime

I always end up leaving the key in the on position and killing the battery, but otherwise yeah, I use the cbr battery and for the most part it works great.

i did the cbr battery conversion, it has a lot more cold cranking amps than the stock battery

I always used the CBR battery because I had problems with mine starting after it was hot. I was only running 13.5:1

Thanks guys I am taking it to my buddies shop after work and he is going to adjust the valves and do a run through on it for me.

i use an optimate 4, its been plugged in for around 3 months, it tests the battery every 30 mins and charges it when and if the voltage drops down from now being used
sam