Author Topic: xbr500 starter problem  (Read 1538 times)

welland99

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xbr500 starter problem
« on: October 08, 2013, 10:20:43 PM »
My starter motor has suddenly developed a fault on the XBR.  Although it is working, it is lacking power (turning slowly) and it makes a high pitch sound when operating.  (Thank goodness for the kick starter)

Has anybody else experienced this?  Any idea what the problem could be?

Are new starters available for these, or do i need to consider repair or 2nd hand replacement?

guest295

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Re: xbr500 starter problem
« Reply #1 on: October 10, 2013, 07:01:35 AM »
The starter's easy to remove. Sometimes the brushes wear down and need replacing. It's always worthwhile in any case, when you're in there, to clean out the gaps between the commutator segments to ensure that a build-up of carbon isn't shorting between them. But starter problems on that motor are more often in the starter clutch.

welland99

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Re: xbr500 starter problem
« Reply #2 on: October 15, 2013, 11:10:17 PM »
Thanks for your reply.   ;)

Is it an easy job to replace the brushes (if needed)?

I'm not familiar with motorbike starters; do they not have a bendix drive like starters on cars?  Can you explain how the starter clutch works, and whether it might be repairable (what usually goes wrong with them?). 

Propellor

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Re: xbr500 starter problem
« Reply #3 on: October 16, 2013, 05:56:35 AM »
Thanks for your reply.   ;)

Is it an easy job to replace the brushes (if needed)?

I'm not familiar with motorbike starters; do they not have a bendix drive like starters on cars?  Can you explain how the starter clutch works, and whether it might be repairable (what usually goes wrong with them?).

Most "jap" style starter motors seem to drive via a sprag overrunning clutch. Look that up on google and google images. Basically there are a series of little metal wedges, specially shaped, set out in radial fashion and sitting between an inner and outer "race". The basic idea is that, in the direction of power transmission, these wedges lock into place and transmit drive. Then, when the engine fires, the rpm downstream rises beyond that of the starter motor. At this point the wedges lift a tiny amount and effectively skid. There is a supply of lubricant so this skidding is not as bad as it sounds, though, eventually, wear will occur and the surface of the races and also the sprags (wedges) become scored or even fatigued/chipped. This is when the sprag clutch can't transmit the required power to crank the bike. It also generates some noise.

So, no, the sprag clutch is nothing like that found on most car starter motors.

The sprag clutch is commonly used in industrial power transmission, usually as a back drive locking device. One example is on the gearbox of an Archimedes screw pump, which amazingly are still commonly used. The same thing is found in wheel hubs of 4x4 off road cars I believe. Amazing little devices!
BEIGE is all the rage

welland99

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Re: xbr500 starter problem
« Reply #4 on: October 17, 2013, 10:01:43 PM »
Very interesting.  never heard of a sprag clutch.  Thanks for the info. 

Propellor

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Re: xbr500 starter problem
« Reply #5 on: October 18, 2013, 05:47:06 AM »
Very interesting.  never heard of a sprag clutch.  Thanks for the info.

Don't take the bit about 4x4's as gospel. I may be wrong with that bit!

The Archimedes screw pump though, has to be seen to be believed. They are usually enormous and seem to revolve pretty slowly. Then you look what comes out the top! The flow is vast.

Nowt new under t' sun.

Edit.  Just looked on you tube and came across an example of one doing the opposite. Water running down it generates power. Fantastic.

Old Archimedes will have a smug grin on his face up in the heavens.
« Last Edit: October 18, 2013, 05:51:54 AM by Propellor »
BEIGE is all the rage

SteveC#222

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Re: xbr500 starter problem
« Reply #6 on: October 18, 2013, 01:37:44 PM »
If you need the Starter Motor section of the workshop manual PM me your email address and I'll send you a copy.
Growing old is inevitable, growing up is optional!

welland99

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Re: xbr500 starter problem
« Reply #7 on: October 21, 2013, 10:06:06 PM »
If you need the Starter Motor section of the workshop manual PM me your email address and I'll send you a copy.
Thanks for the offer, but i think I'll be OK as I have a copy of the whole manual. Just had a quick look and it seems quite complex to remove and dismantle the starter.  Will have to leave that for when I have more time. 

For now, I'm using the electric starter sparingly and relying on the kick starter when possible.    :-\

welland99

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Re: xbr500 starter problem
« Reply #8 on: March 09, 2014, 09:47:23 PM »
Still haven't got around to looking at the starter, but it remains on the list! :-[

Anyway, just thought of a new question.  If I remove the starter motor for examination / repair, is the bike still rideable without it?

Moto63

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Re: xbr500 starter problem
« Reply #9 on: March 10, 2014, 04:40:53 PM »
Hi welland99. I have decent starter that came off my cafe racer project bike if you do decide you need one let me know,  cheers moto63

welland99

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Re: xbr500 starter problem
« Reply #10 on: March 11, 2014, 07:44:17 PM »
Hi welland99. I have decent starter that came off my cafe racer project bike if you do decide you need one let me know,  cheers moto63

OK thanks.  Do you know what model year it came from?  Am I correct in thinking that not all XBR starter motors are the same?

guest1230

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Re: xbr500 starter problem
« Reply #11 on: March 14, 2014, 09:54:03 AM »
Just a thought but have you had the starter gear cover off?

I did to clean and polish mine. Put it back on without correct thickness of gasket (i.e. sealant only!) This took away the required clearance from the end of the starter shaft and slowed my starter down. Re-did it with decent sized gasket and all was well.


welland99

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Re: xbr500 starter problem
« Reply #12 on: March 16, 2014, 11:24:12 PM »
Just a thought but have you had the starter gear cover off?

Thanks for the idea, but no.  I haven't touched it. 

Moto63

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Re: xbr500 starter problem
« Reply #13 on: March 22, 2014, 10:25:38 AM »
Morning welland99, the starter motor came off an 86 or 87 bike, I,m not sure if there is any difference between the years. Cheers moto63

welland99

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Re: xbr500 starter problem
« Reply #14 on: March 24, 2014, 09:51:53 PM »
Been doing a bit of testing, because I wanted to be absolutely sure that the battery wasn't the cause of the problem. 

With the engine kill switch OFF, I tried operating the starter:
1) It turned slowly for a couple of seconds then stopped (probably on a compression stroke).  Subsequent attempts resulted in only clicking solenoid. 
2) Kicked it over slightly to get past TDC, then tried the starter again.  Same as before.  Worked slowly for couple of seconds, then just clicking solenoid. 
3) Kicked it over slightly to get past TDC, then tried the starter again.  Now,  all it will do is click the solenoid. 

So, it could be the battery!   :-\ But, the headlight still illuminates brightly. 

4)  connected jump leads to my car battery and tried starter again.  Now the starter works again, faster than before and keeps going as long as I want (in short spells of about 5 seconds). 

Hmmm.  So it could it could be the battery then !! ???

5)  Decided to try again without the jump leads.  Jump leads had been connected for only about 2 minutes, but now they are disconnected.  Starter continues to operate the same as it did when the jump leads were connected.  Ie it works at medium speed and is consistent. 

Hmmm.  Surely having the jump leads connected for only 2 minutes did not recondition the XBR battery sufficiently to make this much difference?

6) Tried again with jump leads disconnected and suddenly, the starter speeds up to the proper speed.  It continues to operate at the proper speed for lengthy periods (at least 5 second bursts) even after repeated attempts over the space of 10 - 15 minutes.  No sign of slowing.  It's working better than it was when the jump leads were connected!! ;)

So, the battery is strong! 8)

What could be wrong with the starter motor that makes it sometimes not work at all,  sometimes works slowly and sometimes like it should? :o

Can't see any loose or corroded connections. 

It did cross my mind that it just needed to be used; perhaps dirty contacts in the commmutator or something.  But thinking back to just before the problems began sometime last summer / autumn, the starter had been getting used regularly and it had been working consistently well. 

Hmm....what to do.....? :'(