1985 Vmax tach and running issues

Discussion in 'Electrical' started by Whaven, Jul 1, 2019.

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  1. Jul 1, 2019 #1

    Whaven

    Whaven

    Whaven

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    So I have a 1985 Vmax and I have the oddest problem and can’t figure it out for the life of me. So the bike was my dads old bike and I bought it back and the bike was fine except the carbs needed cleaning and the fuel pump was shot, fixed both those issues and it ran fine for a week, well I go to drop it in 1st and the tach starts going crazy and the bike starts backfiring and won’t idle. The weird part it was intermittent, if the tach was behaving normal the the bike ran fine, if the tach started freaking out the bike wouldn’t run well at all. Now it won’t run right at all, the bike will start if I hold the throttle some but it back fires like crazy and the tach either doesn’t work at all or freaks out. I’ve gone over the entire ignition system (coils/plugs/wires the whole deal), I’ve checked the stator, R/R and pick up coils and everything checks out and I’ve checked and clean every electrical harness and ground wire on the bike and nothing has gotten better. The only lead I have is that the three white wires in between the R/R and the harness the comes from the stator get quite hot but that’s all I got and the situation. Would love some help
     
  2. Jul 1, 2019 #2

    jdeitz1979

    jdeitz1979

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    Gone over the entire ignition system how? With a volt meter and the service manual?
     
  3. Jul 1, 2019 #3

    Whaven

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    Yes. Went over everything and it all checks out to factory spec
     
    Last edited: Jul 2, 2019
  4. Jul 3, 2019 #4

    gentsvmax

    gentsvmax

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    Try Sean for his electrics "Known good" kit. There in the kit along with every other component you'll swap out is a resistor, its for the side stand and a couple other circuits, be sure to change it out.

    Unless someone,anybody here walks with you step by step in the trouble shooting process, electrical like carburetion is hard to diagnose over the posts like this.
     
    Traumahawk likes this.
  5. Jul 3, 2019 #5

    Whaven

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    As you might have noticed I’m new to the forum, who is Sean and what is this electrical kit for? Ya, I know it’s a hard thing to diagnose over a forum but I thought I might get lucky with someone that might have had the same issue. Thanks man
     
  6. Jul 4, 2019 #6

    one2dmax

    one2dmax

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    I'm Sean lol and as you'll rapidly find out many people refer to me when you need parts, service, or help beyond what this great group already provides. I have things like loaner electrical test kits as well as loaner shim kits. We make all sorts of custom parts, stock many new OEM maintenance type parts, and have a large selection of used inventory (some aftermarket used and a lot of stock used stuff).
     
  7. Jul 4, 2019 #7

    Whaven

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    Man what a great group of guys. Awesome man thanks for the info. Since you seem to know your stuff what do you think my next course of action should be? Because I’ve hit a brick wall with this bike
     
  8. Jul 4, 2019 #8

    one2dmax

    one2dmax

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    Either bad CDI box or something in the charging system (or bad battery).
     
  9. Jul 4, 2019 #9

    Whaven

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    Ok. I guess I’m going to have to replace the CDI because the battery is brand new and every thing on the charging system checks out. Not looking forward to spending the 900$ish bucks for a new one but it is what it is. Thanks for the help man
     
  10. Jul 5, 2019 #10

    gentsvmax

    gentsvmax

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    Throw an Ignitech and C.O.P.s to the mod monkey to get things rollin.:cool:
     
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  11. Jul 5, 2019 #11

    one2dmax

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    Email me! I have options and can loan you a kit to test with before you have to buy one. I have dyna 3000's and initec's available for a lot less money then $900
     
  12. Jul 5, 2019 #12

    Whaven

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    Yeah COPs would be nice, never looked in to them what would be some that you’d recommend? Also I went on ignitech website and I saw nothing about them making a Ignition box for the vmax or even Yamaha for that matter, if you had a link that’d be cool
     
  13. Jul 5, 2019 #13

    Whaven

    Whaven

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    sounds good man. Where can I find your email?
     
  14. Jul 5, 2019 #14

    caseyjones955

    caseyjones955

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    Let me first take a moment to extend to you a welcome to the forum!

    Yea, what he said.

    I would like to X2 the notion of going with an Ignitek TCI and COPs, but I would hate to push this idea and you still having a problem elsewhere. Your factory coils and TCI are going on 35 years old, if this bike is a keeper for you I would seriously consider this even sans any trouble. Ignitek TCI and stick coils (COPs - Coil On Plug) = good deal of benefit without significant expense.

    With Ignitek and COPs;
    You will never have to clean the gunk out of the noses of the coils where the HT leads plug in
    You can shed the (not insignificant) weight of the venerable factory coils and eliminate HT leads and plug caps altogether.
    You get a programmable rev limiter with the Ignitek TCI, it's quite easy to sweep past the redline if tuned right and not careful. If I'm not mistake the Ignitek kit also comes with a MAP sensor, more upgraded tech.
    The Ignitek can control the Vboost, OEM Vboost controllers are known to get flakey after a few decades of service.

    On my 89 Venture (think of a Vmax with 30% less power and 30% more weight) I did go with the Ignitek and COPs. I think the Ignitek is around $300 retail but Sean can give you an exact quote. I made my own COPs but you can get some very nicely made COP sets from Sean as well. When I ride I gravitate toward places where people are NOT so I need my bike to be as reliable as possible. I would go Ignitek and COPs right away on any Vmax or Venture I may buy in the future.

    I'm a DIY guy aside from being a commercial grade cheapass so I did the COPs myself, a link here that contains tons of good info on COPs from the Venture side, including the ones I did (page 4). It's almost the same procedure for Vmax.
    https://www.venturerider.org/forum/showthread.php?102440-Run-for-it-it-s-the-COPs!

    Congrats on the cool steed!
     
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  15. Jul 5, 2019 #15

    one2dmax

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