Question about replacing batteries

Jamps

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Hey everyone,

I'm super new to this forum and super new to the XS400.

I recently picked up a 1979 XS400F and the battery is real old, and real dead. I really want to replace it with a maintenance free battery but I can't seem to find one that says it works for the 1979 model.

BikeBandit says the Bike Master AGM Platinum II fits the 79 model, but other sites say its only for a 1980-81 even though it says it is a replacement for the 12N12A-4A-1, which is what this 79 had already. Is there really a big difference? If anyone could tell me if this battery would work, or point me in the direction of one that does I'd be really grateful, I wanna ride this thing!

Bike Master AGM Platinum II link for reference - https://4into1.com/bikemaster-agm-platinum-ii-battery-ms12-12a-4a1/

Thanks,
Jamps
 
If you have already fitted that exact battery in place the new one should work too. Application lists are often woefully incorrect.
 
If you have already fitted that exact battery in place the new one should work too. Application lists are often woefully incorrect.

thanks for the reply. I spoke with Bike Master this morning and they told me that all the XS400 bikes used the same battery, which I'm sure is common knowledge around here. So they said I could use the AGM or True gel 12N12A-4A-1 replacements instead of the conventional battery. [I got the AGM.]

After I get the battery in, it's time to kick! This is my first kick start bike, and I'm excited to exhaust myself trying to start it.

Thanks again!
 
The F 79 should have a e-start also. The 79 2-F is a kick only. Post some pics of the bike.
 
The F 79 should have a e-start also. The 79 2-F is a kick only. Post some pics of the bike.

Yes you're right, It does have an electric start but it wasn't functioning when I bought it. I just get a click when I press the button. I'm hoping that was just cuz the battery was crummy, otherwise I have no idea. The Starter motor, maybe?

I'll take some pics when I go put the new battery in for sure.

Thanks!
 
Could be something as simple as a starter solenoid too. With a bit of effort you can often adapt say a $20 rider lawn mower solenoid to take the place of a super expensive exact replacement factory part. Been running one for years on my CB550F, the quickest $60 I ever made out of thin air.
 
Lots of stock oem ones can still be had for cheap. Yamaha used them in a bunch of bikes. I have a bunch of them. Just plug and play.
 
Lucky y'all then, commonly they go for $80 on the big Hondas. Ridiculous. Part of it being the timidity of people to think OEM is the only thing that will work. When you can run 2 inches of wire to save $20 I go for it, none of my stuff is 100% OEM but it doesn't break either. I do the same with the cars to save $$$$ megabucks too.
 
Thanks for the advice everyone.

Is there any kick starting advice you have for me?

A technique, or the steps I should take, or things i should never do?

I really am only used to electric start bikes.
 
Make sure you are in neutral, kill switch is off (on), gas turned on and use the choke if cold. If engine is in tune and good shape it should start on first kick. It's small enough you shouldn't have to move engine to get on a compression stroke, they don't kick back like a big single will.
 
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Make sure kill switch is off (on) and use the choke if cold. If engine is in tune and good shape it should start on first kick. It's small enough you shouldn't have to move engine to get on a compression stroke, they don't kick back like a big single will.

I know that the previous owner had to kick it many times before it would start-up. My assumption was that when I bought it the carbs probably need a good cleaning.
 
Could be other things like timing too. if points then they need to be kept pretty sharply on spec. Out of a hundred bikes I've had only two show any starting issues, one had water ingress into the magneto and it simply would not kickstart, you had to pushstart it and forever until it lit off. Cleaning the mag rust off and points up to reset them had it then kicking easily to start with only a half kick. I was just young enough I didn't know about such things and Dad showed me what to do. The other bike was simply dead worn out, the rings were broken in several places and why. Both once running would run forever, they just wouldn't start reliably.
 
Could be other things like timing too. if points then they need to be kept pretty sharply on spec. Out of a hundred bikes I've had only two show any starting issues, one had water ingress into the magneto and it simply would not kickstart, you had to pushstart it and forever until it lit off. Cleaning the mag rust off and points up to reset them had it then kicking easily to start with only a half kick. I was just young enough I didn't know about such things and Dad showed me what to do. The other bike was simply dead worn out, the rings were broken in several places and why. Both once running would run forever, they just wouldn't start reliably.

My service manual comes in the mail today, so that should hopefully help me with troubleshooting that stuff.

I'll let ya know how it goes as it goes,

thanks!
 
So, I put the new battery in and the starter functions again! Huzzah!

However, after hitting the electric starter a few times and after what felt like 40 kicks I couldn't get this engine going.
There were a few kicks where it started for a second but it gave up quickly, and then eventually so did I.

Gunna look at the spark plugs next, and then I guess the carbs.

Here's a pic of it too.
 

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Update:

Got the bike running using the electric starter yesterday! And then after it was warmed up the kick starter would also work, by 2nd or 3rd kick it was good.

Funny thing though, the choke had to be pushed in all the way or else it wouldn't start at all, and this is a cold start after it sitting in the garage a few days. And if I pulled it out during warm up it would die.

Anyone have a similar issue like this?
 
It's normal behavior. You must use choke to start but then you get it off as quickly as you can without killing the motor.
I meant that during the first cold startup I couldn’t use any choke. But maybe the garage was warm enough that the bike wasn’t that cold?

Also, do you know the size of the rear brake bleeder screw on the 79? I can’t find the info in either my owners manual nor the service manual.
 
UPDATE: I took out and rebuilt the carb, and replaced a broken off air mixture screw. The bike now starts on first kick and immediately with the electric start. The breaks work now too, and the bike no longer jumps in RPMs when I turn right [cable was caught somewhere.]

There was a leak underneath the engine, I replaced all the bolts and gaskets for the oil filter and sump. So all that seems to be squared away.

The bike essentially works now. It just needs new shocks, and the mufflers are apparently rotted away, but other than that she good!
 
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