'85 VF500 interceptor no spark

Discussion in '1st & 2nd Generation 1983-1989' started by John painter, Apr 15, 2018.

  1. John painter

    John painter New Member

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    After years of off road riding I sold my old XR600 a few years ago, it was an excellent bike, but age and reality caught up with me - kick start 600cc bikes (especially in cold climates) are for younger people. So I recently had the opportunity to purchase an '85 vf500 interceptor for $200... How could I resist? It's all there and in pretty decent shape considering it was stored in a guys woodshed here in Maine. I was inclined to believe him when he told me it was running last year but he broke the starter switch and choke cable. So I was able to replace the choke cable without much issue, the starter I have at the moment rigged to try to fire the bike up.

    This is where I'm looking for some suggestions - I have no spark. I've read several posts on interceptors without spark so I have several questions from others with more experience. The previous owner broke the starter switch so I just use a piece of wire to jump that circuit (see photo, I jump yellow/red to black/red) so the starter cranks - if I can get it to fire I'll invest in a whole new on/off starter assembly. For now, if there's something else which should be jumped to get it to fire, please let me know.

    On my coils I have 2.7 ohms on the primary side and 13.7 ohms on the secondary side, after reading through the Clymer's manual I see the primary should be 2.8 ohms and secondary 2100 to 2800 ohms. If this is the issue, shouldn't I at least see a faint spark on plug? I see no spark when I crank it. Again I'm interested in any suggestions.

    Another interesting issue, my fuel pump is not running when I crank the engine (I have unhooked the pump and it pumps fine when connected directly to a 12v battery), I had read on one of the threads here that the fuel pump will not run unless the coils are functioning correctly. Is that true? I could not find a reference to that in the Clymers manual. I would have thought the CDI might control the fuel pump and maybe two bad CDI boxes could be the issue.

    So I'm looking for some suggestions of how to approach my no spark issue.

    Thank you for any suggestions. :Help:

    starter.jpg
     
  2. John painter

    John painter New Member

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    Well, it was easier than I thought to get things going. After thinking for awhile and looking at the wiring diagram thank you @hoobatech , I realized I didn't have everything jumpered on the start switch that I should. Just in case anyone ever runs into this scenario (since I understand it's common on these bikes) and the right side controls are messed up, this is how you need to jump the switch.

    The black wire on the back jumped to the red/black on the front, and the red/yellow wire jumped to the red/black or top right contact, and if you want to see if the head lights are working blue/white jumped to the red/black.


    s2.jpg

    s1.jpg

    When that is connected this is what you get - a running bike. In person the engine sounds smoother and way quieter than my old XR 600! I don't hear any chain slap, ticking, or anything other than the very smooth whir of a four cyl engine - sounds better than my Volvo v70. :cool:

    I can rev the engine, and though it sounds a LOT more aggressive, and tach's way up there when I give it the corn, it still sounds very smooth. It's hard to get over the difference between this 4cyl 500 and the single cylinder 600 on my old XR.



    Now I just need to get the front brake unstuck.:Drum:
     
    Last edited: Apr 17, 2018
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  3. jeremyr62

    jeremyr62 New Member

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    Well done. Those F1 end cans will make it sound better then stock BTW. VF500s need lots of TLC but are a great bike.
     
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  4. John painter

    John painter New Member

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    Any pointers on the type of TLC the VF500’s need?
     
  5. jeremyr62

    jeremyr62 New Member

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    Just the engine. They can drop valves at low mileages if not looked after. (They can drop valves if looked after too unfortunately) Check the valve clearances religiously. Make sure the oil is good, the fan works and the cooling circuit is in good order. Some recommend not revving above 9K but there's no evidence either way this helps.
     
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  6. John painter

    John painter New Member

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    Thank you this helps! Now that I know the bike actually runs, I will get down to all the basics; replace all the fluids, filters, etc, etc and add your suggestions to the list. Thanks!
    :wheelie:
     
  7. John painter

    John painter New Member

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    I replaced the busted starter switch throttle assembly, and the bike stars reliably. Though I guess I’m only delaying the inevitable carb cleaning.

    I’ve ridden on my street a few times to get a feel for what’s going on with the bike and it lags in all gears when giving gas. It also revs on its own when parked and idling.

    My question is what to look for, or look out for and pay attention to in removing, cleaning, and reinstalling the carbs. I’m reading all the posts here, and have printed the download version of the Clymers from this forum. I’ve rebuilt plenty of single carbs but never four of these Interceptor bad boys.

     
  8. jeremyr62

    jeremyr62 New Member

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  9. John painter

    John painter New Member

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  10. squirrelman

    squirrelman Member

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    I have tons of VF500 carb rebuilding experience, spare parts and proper tools. I've helped dozens of our members by servicing every type of VFR carbs, and i'd like to go over yours. done right first time. when i'm finished, your carbs would be restored to original performance.

    Please PM if interested in my service.

    91116 008.JPG

    91116 041.JPG
     

    Attached Files:

    Last edited: May 9, 2018
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  11. John painter

    John painter New Member

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    Thank you @squirrelman!

    I am proceeding slowly in understanding the Gen 1, VF world, especially since this is my first foray away from big single piston off highway thumpers and into more than two carb bikes - let alone street bikes. What was I thinking? Oy vey! But hey, I only paid $200 for the bike. :D

    I may very well take you up on your offer, though before then I am getting acquainted with the bike and whether I want to get into the money an old bike like this will cost. It is good to see there is an active and helpful community here!

    While I was initially trying to understand what was and was not happening with the engine revving like it does I got my tools, cell phone, and some bandages and Tylenol (just in case) crammed it into a couple riding bags I have and rode around a bit. It really feels like carb stuff, the way the engine hesitates rhythmically whether gently cruising or accelerating, and since I ruled out intake boot air leak and am reading a lot of posts about how picky the carbs are, and how I acquired the bike, well it got clear what the likely culprit is. I do need to check the fuel filter, though new, I noticed a small fuel leak so it's possible it is dud and I need to replace the replacement.

    Despite weighing a ton, and a previous owner putting over size tires on it which makes turning somewhat like driving an old Volvo with snow tires in the summer, I have to say it is the most comfortable street bike I've ever ridden, surprisingly nice ergonomics everything is in just the right place - no wonder there is still a fan base. It's a Goldilocks bike!

    IMG_1198.JPG
     
  12. jeremyr62

    jeremyr62 New Member

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    There's no doubt about it, the carbs on the V4s have caused more grief than any other part of the bike. A good set of clean carbs is a must if you are trying to resurrect a bike. If you know the carbs are OK it makes finding the other issues a lot easier.
    When you get around to removing them you might find it difficult, but it like anything, it gets a lot easier with practice. Takes me about 30 minutes to swap a set now, so it isn't inherently difficult.
     
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  13. John painter

    John painter New Member

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    OMFG!

    I have never.... ever seen such crappy carbs that run. I decided to pull the carbs after work so that I could clean over the weekend since the weather is supposed to be crappy. I've had some gummed up carbs, like when I rode two stroke enduros (my PE 250 in particular was varnish factory) I always seemed to have crap in the carbs even when I was riding all the time.

    Wow, thank God I there are some wicked smart people on this site with excellent info on these old 4 carb bikes.

    While I won't get into really cleaning until tomorrow and I'm rested, I had to take the bowl off one of the carbs to have a look. And this is what I found.

    1.jpg

    But wait, it gets worse...

    2.jpg

    I feel so bad making this sweet, sweet, bike run with crap like this in its carbs :Cry:

    3.jpg

    It took me 20 minutes just to clean this one jet

    4.jpg

    This is what came out...

    5.jpg

    I don't even know how all of that fit in there!!!!! Steven Hawking is gone, and I don't know who else could find an explanation in physics to explain how this much matter could possibly be caked in that jet.

    But a little time and patience...

    7.jpg

    And the bowl cleaned up pretty good too.

    6.jpg

    My carb cleaning adventure is only just beginning, so I need to get some rest for tomorrow. I've got five cans of carb cleaner and I think at this rate I'll end up using them all. I also plan to rub down the whole exterior of the carbs with Marvel Mystery Oil, I like the way it cleans up old aluminum while leaving a patina - after all I only paid $200 for the bike so I'm not into doing a full resto, but clean carbs should help me figure out if this bike is a keeper since everything else is managable.

    I'm open to all suggestions on places to pay attention to for cleaning which may have issues in these carbs, what cleaners to use, etc, etc. I'm trying to clean one carb at a time, taking one apart at a time to reduce the potential of mixing anything up between the carbs since I'm not familiar with them yet.

    Suggestions?

    :chaingun:
     
    Last edited: May 18, 2018
  14. jeremyr62

    jeremyr62 New Member

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    A cheap ultrasonic cleaner will make the job much easier and quicker and better.
     
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  15. John painter

    John painter New Member

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    Carb is cleaned, back in bike, bike won't run, only starts with starter fluid for a moment. The fuel pump is working but only the left side carb seems to have gas, right side is dry. Is there a step I've forgotten? Is there a way to prime the carbs?
     
  16. jeremyr62

    jeremyr62 New Member

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    Keep flicking the kill switch on and off to prime the carbs.
     
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  17. John painter

    John painter New Member

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    Now I'm confused. How does that prime the carbs any differently than not hitting the kill switch, and just pressing the start button? Now I'm second guessing myself, the bike turns over with the key on but kill switch to off. Is that correct? Is that what somehow gets fuel to the carbs?
     
  18. jeremyr62

    jeremyr62 New Member

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    Put your hand on the pump to feel the pulses or listen to it. Flicking the switch activates the pump to prime the carbs. Alternatively if you just want to check if it can run, set up an auxiliary fuel tank and bypass the fuel pump altogether. It depends what you are trying to achieve.
     
  19. squirrelman

    squirrelman Member

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    Or u can use a jumper wire at the pump relay to fill carbs b4 starting. almost certainly a sticking float needle if no gas in one carb. dija remove and clean the needle and seat and small filter above it ? dija flush out the fuel tank on that 500 after removing the petcock ?

    if your bowl gaskets are embedded with crud (in photo) and hardened up, best to replace them.

    i never trust that the idle jet is fully open until after i've pushed a .010" steel wire through; just seeing a bit of light is no guarantee.
     
    Last edited: May 19, 2018
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  20. squirrelman

    squirrelman Member

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    my buddy bought the standard HF u-s cleaner, and it stopped working after only about 6 uses @!!!!!!!!!!!!!!!!! More Chinese garbage !
     
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