Total Motorcycle Community Forums

the starter motor slips on my xs400 when I try to jumpstart it with a car battery. While getting the bike inspected, the mechanic told me that the car battery dumps too much ampereage into the motor causing it to slip.

I have noticed that the motor used to turn faster with the car battery (My motorcycle battery has since died, and I can only kickstart when the engine is warm). But I didnt entirely buy his explanation... has anybody else come across this before? The starter turns the engine for one stroke, and then just whirrs. Once in a while it does manage to turn then crank for 2-3 strokes and the bike starts right up.

So will a new fully charged motorcycle battery possibly solve this problem, or will I have to check out the starter clutch/chain? I'm wary of doing this as it would mean new seals for that side cover and Im already broke

Something also needs to be done about my rating. Im hardly a "veteran" unless its asking questions.

Whether car battery or bike battery, providing they both put out the same voltage, the starter will draw the same amperage. The starters on those old Yamahas were never regarded as good at the best of times.

If the motor is in decent shape it should start readily on a couple of kicks, whether cold or warm. It may be that you need to learn how to start it whether cold or warm motor.

As for what is needed to prevent what I think you are refering to as "slipping" you may need http://www.oldbikebarn.com/motorcycle_p ... bike=XS400

the starters on the old Yamaha bikes were only on there to plug an existing hole in the engine.they were never intended o crank the engine.i determined this after trying to get some xs400's and xs500's to crank.

Hmm... maybe I could use the exercise and kickstart. Anyway, for when I have the time and money, any mod suggestions that would alleviate this problem??

Oh BTW. Besides a fullly charged battery, whats a good way to have 'er kick-start reliably? New wiring? etc..?

If the motor is in good running order, ie plugs wires etc then pull the choke and it should start with the second kick. My xs 650 does. Mind you, it needs a GOOD kick not a feeble flip over.

Check out the sites for older yamaha twins. I know there are hints for how to improve the starter, just never had to so havn't bothered to keep current with the latest info.