VF500F project update and carb sync questions

Discussion in '1st & 2nd Generation 1983-1989' started by Poligrafovich, May 28, 2012.

  1. Poligrafovich

    Poligrafovich New Member

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    My 500 is roadworthy and legal as of today. I just finished going through what I hope are all the safety and operational necessities as well as some low-budget cosmetic work. The plan now is to shake it out and get some use out of it before considering the nice-to-haves. Background info is here. What I've done:
    • Tires, Bridgestone BT-45 in stock sizes.
    • Wheel bearings seem OK, did not remove or replace.
    • Cleaned and lubed chain. Chain and sprockets were in great shape, probably replaced very recently.
    • Tapered roller head bearings. Originals were badly notched.
    • New fork seals and dust covers. The latter don't fit right and will need replacing. The bushings were in great shape. 10W fork oil.
    • Replaced the front brake pads. Everything else about the brakes seemed fine, so I didn't take them apart.
    • Rebuilt clutch master and slave cylinders. The latter was leaking badly.
    • Removed mufflers, collector, and front header pipes, mostly to get at the oil pan. Cleaned, de-rusted, and painted them while I was at it. 500 degree gloss black engine paint (wil this work?) on the mufflers, 1500 flat black VHT on the rest.
    • Pulled oil pan, cleaned strainer. A little metal grit (imagine a couple of shakes of a pepper shaker) in the bottom. Bosch 3312 filter and Rotella T6.
    • Drained coolant, removed the radiator and removed the ignition, to get at part one of the main event double feature...
    • Adjusted the valves. I must have read every how-to on the internet before doing this. I used the two-feeler method.
    • Dismantled and cleaned the carburetors. I debated about taking them off the plate, but after reading the Mike Nixon book and considering that the chokes were sticky, I decided to go for it. Replaced the float needles and seats, bowl gaskets, and connector pipe o-rings. Couldn't find any new o-rings to fit the idle mixture screws (full kits weren't in the budget) so the old ones went back in.
    Now, to the questions. After reassembly it fired right up and ran very smoothly. However, it wouldn't idle below about 5k. When I took the carbs apart I didn't touch the balancing screws, with the (bad) idea the old settings would be a good enough starting point for an on-bike sync. Poking around I discovered that the #1 throttle butterfly was the only one completely closed. The others were still open just a hair; gently pushing any except #1 would cause the RPM to drop. I've read quite a bit on syncing carbs but don't remember ever reading of too-high idle being a symptom. Is this correct?

    Anyway, after a token effort at adjusting on the bike, I pulled the carbs and did a careful bench sync using a strip off the edge of a dollar bill. After this the idle dropped to a bit above 2k. I took this to mean I'm on the right track and that a proper on-bike sync might well be enough to make it right. Is this reasonable, or does it look like I missed something further in? It was good enough to ride, though. I took it for a spin and had an absolute blast. This was my first real ride on one of these and I was not disappointed.

    One more question: What's the tool of choice for turning the balance screws on the bike?

    carbs.jpg

    vf500f.jpg
     
    Last edited: May 28, 2012
  2. commrad

    commrad New Member

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    I can't really help with your carbs. I did a mechanical sync on mine per the manual and it runs pretty darn good. Careful on those BT tires, I put about 1000 miles on mine before they were so thin they started getting holes in them from tiny pieces of gravel on the road, still had over half tread left though.
     
  3. Michael E

    Michael E New Member

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  4. commrad

    commrad New Member

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    oh yeah, if you find you have a flat spot in the mid range once you get it going shoot me a PM with your address. I'll send you some brass shims for your needles. I only needed 12 for both bikes but had to order 100 to get em. I'm doing my v45 Sabre at the moment. My baby Ceptor was pretty flat between 4 and 7k rpm, now that's where it seems happiest and it pulls harder (LOL) above 9k especially when I have the slip ons on it. I'm not sure why but my mileage increased from 37 to 41 after the shims with stock pipes and went from 35 to 42.5 with the slip ons. My milage would be better but the only time I get below 70 is in town and those are rare moments.
     
  5. Poligrafovich

    Poligrafovich New Member

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    Well, I finally got my balancing rig and adjustment tool rigged up, so I got my first experience syncing V4 carbs today. It does seem that the out of balance condition was the explanation for the inability to get the idle RPM into spec. As the adjustments improved the idle speed dropped right down to where it could be set wherever I wanted it using the idle stop screw.

    Man, does this thing purr! :smile:

    1.jpg

    Here's what I came up with for a tool. A couple of pieces of copper tubing and selections from the Craftsman Collection. It worked very well, though I could only get to the #2 screw with my lovely assistant holding the throttle partway open. This wasn't much of a problem since I decided I was more comfortable making adjustments with the engine stopped anyway.

    3.jpg
    4.jpg
     
  6. creaky

    creaky New Member

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    Very clever idea on the tool!! It's always good to see yankee ingenuity at work.
     
  7. Poligrafovich

    Poligrafovich New Member

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    My particular flavor of yankee ingenuity hails from the Tennessee hills. :smile:
     
  8. squirrelman

    squirrelman Member

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    After moving any synch screw, you need to snap the throttle a few times so that the butterflys and linkages can settle into position proppaly.
     
  9. Poligrafovich

    Poligrafovich New Member

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    Yeah, I figured this out somewhere along the line. If it was mentioned in any of the how-tos I read beforehand, it escaped my attention. A valuable piece of advice.

    Now that it's running well, how long is it gonna be before I drop a valve?
     
  10. crustyrider

    crustyrider New Member

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    If you take care of that little pig you shouldn't drop anything... proper care and it will run forever.. if you abuse it..who knows maybe never but maybe sooner than you want.. post up some close ups of your Sync tools (the IV bottles) and how about a little write up on how you made it?
     
  11. crustyrider

    crustyrider New Member

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    If you take care of that little pig you shouldn't drop anything... proper care and it will run forever.. if you abuse it..who knows maybe never but maybe sooner than you want.. post up some close ups of your Sync tools (the IV bottles) and how about a little write up on how you made it?
    it might be a bit easier to sync the carbs with the tank off ( fuel from another IV bottle)... I need to sync my 86 but I don't have the dough to buy a real sync tool...
     
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