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Yamaha XV250 Regulator Issues

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by zero_cool, Dec 27, 2008.

  1. ello all biker tech heads!

    I have a wee bit of an annoying problemo here

    I have obtained an XV250 for a short period of time
    however it is having some issues that are bugging me to no end.

    I've Narrowed the issue down to what I feel is the problem - the regulator.
    This has been replaced previously as it was causing some issues,
    was replaced and BAM the bike is fine again
    but now it has appeared again less than 2 months later and is starting to get annoying.

    after going for about a 10~min ride the Regulator heats up so much that you cannot touch it. (could probablly get some nice charred marks on a steak) the bike will eventually stall when it is hot and idling.
    (possible voltage breakdown due to the heat?)

    if you leave the bike for 10mins, the regulator cools down and the bike will start again without a problem.
    occasionally when riding it will miss here and there,

    I have pulled the bike down and tried to check for anything that has frayed / crossed wires and have been unable to find anything so far.
    I've never come across something like this before
    It seems like an earthing / something has crossed but I can't find anything?

    It has a new battery
    System charges at 13.5v at idle
    and jump upto 14.2~ when the revs are picked up.
    No other loads are placed onto the system when this test was done

    Bike Age - 1996
    Kms - 56xxx
    Previous History - Had issues before with not starting and the carbies were pulled off and rebuilt. (seals, jets etc)
    New spark plugs have been fitted less than 500kms ago.

    Would anybody have a service Manual or know where to locate one for this bike or possibly point me in a direction on what to look for?
    I had a look at the troubleshooting threads but did not locate anything specific.

    If you Require any further information,
    let me know!

    Thanks So Much.

    /is confuzzled

    - Brad
  2. I don't know the particular Yamaha regulator but heat is the enemy of electronic components. Many regulators use the base plate to transfer heat to the frame of the bike. This heat transfer can be hit or miss so its best to use some Heat Transfer Paste so that the transfer of heat to the frame works at its best.

    Failing that it is possible that you have shorted turns on your alternator, this causes the regulator to have to work much harder to maintain charge current and maybe overheat.