XBR500 Electric start

[guest1571]

I have recently purchased an XBR500 with the earlier electric start sprag clutch ( with the flat cover over the starter gears ). How fragile is this set up and if it breaks does it do any damage ? As a precaution I have been starting the bike from cold with the kick starter. I then use the electric start from there on. Does anybody know if the later starter arragement can be fitted to the earlier bike ? Any info or experience with this will be greatfully received. Thank you.

[rossth]

The sprag 'clutch' is actually a one way bearing, the bearing rollers (sprags) have a flat on them that engage with the bearing outer ring in one direction only.
they are pretty reliable with the weak point being the spring that holds the sprags in the inner bearing cage, when the spring looses tension it allows the sprags to float a little and they can break.
I have replaced a couple of these that would not engage to find a weak spring and some broken sprags, the inner bearing is contained within the outer ring so when and if the bearing fails none of the sprags can get out into the crankcase.
I converted an electric start only xbr to kick / electric and took everything i needed from a xl600 dirt bike bottom end, I cant remember exactly what parts i took from the xl but everything i needed was there.
hope this helps, Ross

[guest1571]

Thanks Ross. That's very useful. I presume the sprag parts are no longer availlable then ? If not, perhaps the only fix if I get a problem , is to fit 2nd hand parts, of which I presume the later electric start sprag parts are more likely to be available.

[rossth]

The parts are still available new from Honda and I have only ever had to change the inner sprag bearing.
The part number has been superseded a couple of times and the current part number for the inner bearing is 28126-MK5-004
I have purchased one as recent as November 2012 from my local Honda dealer and it was about $60 AUS ( about 40 pound for you)
I have had 86 &87 model XBR's and currently have a 86 gb500 and found them all to be same internally despite the external cover over the starter gears being different.
I would suggest you leave it alone until it breaks which might never happen, if it does it wont do any damage it will just stop engaging
Regards Ross

[guest1571]

Hi Ross. I think you have now put my mind at rest ! I shall take your advice and get on and enjoy the bike. Regards Richard.

[reckless_b]

I would guess that unless your xbr has led a very sheltered life, has only been started with the kick start or has incredably low milage plus all the above, it has more than likely had the sprag clutch changed for the later type, so should be no worries.