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Starter and Big bore

Discussion in 'The Garage' started by dagored, Dec 23, 2009.

  1. dagored

    dagored XS650 Member

    So I'm at a crossroads. I'm wondering if any of you have comments on the XS starter and it's capabilities. I am just shy of committing to a 750/re-phased build. The motor will go into the Hooligan. I am limited rather severely in the size of the battery that I can use. At this point it looks like the Mikes 14ah AGM unit is about as large a unit as I will be able to fit . My back is bad enough that I am unable to kick start any more. Am I headed down a dead end ? I've asked several sources for info on smaller but more powerful batteries. Seems like no one has any info. The Mikes battery has about 200 cold cranking amps. What words of wisdom have you ?
    Marlin72xs likes this.
  2. I don't have any wisdom to share on the 750cc rephase and how hard it is to turn over, but the battery I'm using in my project is an Odyssey PC545. This source says it has 185 cranking amps at 0 degrees and 240 at 32 degrees. http://www.summitracing.com/parts/ODY-PC545/

    It's not cheap but it's a good battery. If I remember correctly, a friend used the same one in his chopper with a 100 inch Evo engine in it. If it is good enough to turn that over I don't think you'd have any problems. Besides, wouldn't rephasing make the engine easier to turn over and the 750cc kit shouldn't make much of a difference unless it's higher compression. :shrug:
  3. inxs

    inxs xx

    - i had some misgivings about removing the estart from my 750 rephase-i have never liked estarts-but have not noticed any difficulties kicking it...some months ago i put my back out and had problems getting my body to do what i wanted-getting old will do this to you sometimes-and had to get my wife to kick it for me-of course then i had to take her with me

    - i was talking to some xsers in holland earlier this year who run estart with these same mods and use a std battery with no apparent problem
  4. hein weijers

    hein weijers XS650 Special (5E6) 1982

    A rephased engine is not easier to turnover. Rephased or not, there is only one piston at a time with compression. With the same compression rate, a 750 cc needs about 15% more Amps of the starter motor.
    By the way: the starter is rated at 500 watt power netto. I don't know what it's peak power is, but even if that is 1000 watt, the current drawn from the battery is only 85 Amps @ 12 Volt.
  5. inxs

    inxs xx

    - what is commonly done on larger bored XSes is to install the decompression mechanism from an XS2-you need the exhaust rocker with the tab on it, the inspection plate with the mechanism and the bar lever...this heavily reduces starter wear and shock load on the crank
  6. @Hein:
    Cool. Sounds like the using the starter with a good battery should be fine on a rephased 750cc.
  7. xsjohn

    xsjohn 8-1 lover

    Grisld1 mentioned to me that he uses a larger battery wire to ground and to the starter to help his high compression start.....

  8. hein weijers

    hein weijers XS650 Special (5E6) 1982

    Yes John, I didn't think about that yet, but at a current of 80 Amps, a resistant of 0.01 ohm of the cable already drops the voltage at the starter with 0.8 Volt! The long cable to the starter is the most important one to look at. Also the connections have to be clean and tight.
  9. Visegrippe

    Visegrippe lurker extraordinaire...

    Just my 2 cents: the e start seems to have no problem cranking mine, which is bored to 780.

    Posted via Mobile
  10. 73novaguy

    73novaguy XS650 Enthusiast

    Just another battery option besides the previous mentioned Odyssey, is Braille. They are pricey but its what they use to start Formula 1, 4 cylinder race cars. I have one in my 113 ci Chopper, the cranking amps are crazy. This is the one I run, 813 Pulse Crank Amps.

  11. Getting your motor to crank, turn over is one issue. The other is having enough voltage available during crank to run the ignition system. Cranking will often drop the voltage so low that the spark is weak or gone. That is why bikes start on one kick when tuned right. All voltage is available on kickstart for the coils and you are getting a good spark.
  12. hein weijers

    hein weijers XS650 Special (5E6) 1982

    True! And that's where the quality of a battery comes in. The higher the internal resistance of a battery, the bigger the voltage drop and the lower the available voltage that remains for the ignition.
  13. xsjohn

    xsjohn 8-1 lover

    Retard the ignition timing just a bit............I find these too advanced anyway..........xsjohn
  14. jay760

    jay760 XS650 Junkie

    Will the actual starter motor turn over a 750, vertually every one I've had made a horrible grinding noise when turning the bike over.
  15. Intuitiveness tells me that it's still the same compression, and you're still only compressing one piston. There *is* a 15% difference between 750 and 650, but that's not asking that much more of the starter. The starter is pretty stout... I think the grinding is probably just a bad bendix.
  16. This might not be of any help but, I am using a battery from a Yamaha R1 Sealed and small. But strong.
  17. grizld1

    grizld1 Grumpy old man Top Contributor

    Displacement: 700 cc. Compression: 180 lbs. Starting system: OEM starter only, kickstart removed (orthopedic issues). Starting issues: None, even below 30* F. Modifications: Upgraded starter motor and ground cables. Years in use: 4. Battery: AGM replacement for OEM unit. Bottom line: Keep everything clean, tight and tuned and the OEM starter will spin a 750 motor just fine.
  18. inkman

    inkman XS650 Member

    hey all, i need to replace the starter in my wifes xs650, only prob is i cant get to 2 of the bolts because of the frame... what is the easiest way to get to them ??????? thanks
  19. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Normally all 4 bolts can be accessed from under the bike. Yes, 2 of the bolts are in a tight location, but you can put a wrench on them..................try using a wrench with an offset.
  20. off topic, but I love it when Johns old posts popup.

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