The VFR that wasn't but now is.

Discussion in '1st & 2nd Generation 1983-1989' started by RogueRC24, Oct 19, 2021.

  1. RogueRC24

    RogueRC24 New Member

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    You make a good case 50.
    I don't plan on hacking this bike apart (like my hawk) although I want those F2 wheels on pronto. I will be saving anything removed and placing in storage, just in case....
    I like the idea of "more rare then an RC30". :)
    This does mean however, that unless I want to cross-reference every o-ring, nut and bolt I will be ordering from wemoto I supose. Unless I find a better source with an actual listing for an 88/89. Anyone..anyone :D
     
  2. 50th VFR

    50th VFR New Member

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  3. 50th VFR

    50th VFR New Member

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    To fit the original silencers you will need to refit the collector box which sits between down pipes and silencers. Unlike the "straight through" design used on the 86/87 models in the 88/89 bikes the gases effectively do a 90 degree turn in the collector and exit out of the side. Exhausts pipes then turn the gases through 90degrees before they enter the silencers.
    So effectively a 4-2-1-2 system.

    Now for the catch. Early Motad downpipes were designed for their 2-1 exhaust. Later versions were modified to allow use with collector box and original silencers.

    Marvin did a good set of look alike exhausts.
    Still available at https://predatormotorsport.co.uk/Honda-VFR750F-88-89-Silencers-Original-Style-Black-and-Aluminium/
     
  4. 50th VFR

    50th VFR New Member

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    Pic of collector box Screenshot_20211125-081252.jpg
     
  5. 50th VFR

    50th VFR New Member

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    I have the official Honda Addendum for the 88/89 model but at 9MB it is too big for forum 4MB limit
     
  6. Captain 80s

    Captain 80s Member

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    Please expand a bit on this. I'm not sure how a system that takes two 90 degree turns on each side is considered an improvement. Seems more like a packaging and manufacturing concession.
     
  7. 50th VFR

    50th VFR New Member

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    The arguement that replacing a 4 into 2 system used in FG/FH with effectively a 4 into 1 system improved the efficiency of the system by allowing all the pulses from the four cylinders help each other in drawing the gases away from the engine.

    4 into 1 was configuration used in RC30 from 87 on and all 750/800 VFRs from Gen 3 onwards.

    This was effectively a 4 into 1 but with two silencers, fed from a single collector to keep the twin pipe balanced look which was still the style the time.
     
  8. Thumbs

    Thumbs Member

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    The Motad system is a complete tuned stainless steel system and produces more power throughout the rev range
     
  9. Captain 80s

    Captain 80s Member

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    OK. I still think it wasn't very elegant in execution and the center stand fitted as stock equipment played a role in that particular design. 86 - 87 center stands were a Hondaline accessory, and pretty rare now. Single sided swingarms on subsequent models likely contributed to the single silencer configuration as well.

    In any case, it obviously worked pretty damn good, but I wouldn't be tracking down and shipping heavy stock parts from Europe just to go back to it.

    Cheers!
     
  10. 50th VFR

    50th VFR New Member

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    Interesting

    The centre stand was standard fit on all years of VFR750s and VFR800s sold in Europe.
     
  11. RogueRC24

    RogueRC24 New Member

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    I threw the center stand in the trash. Just didn't like the look.


    Just kidding. lol
     
    Terry Smith likes this.
  12. Captain 80s

    Captain 80s Member

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    The 90 - 93 VFR didn't even get a center stand in the states as new. And the Hondaline kit was an abomination. This huge slab of steel bolted to the frame so the stand could mount to it. They were HEAVY. I installed a few at the dealership.
     
  13. RogueRC24

    RogueRC24 New Member

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    Hold my Euro trash beer and watch this.
    Thumbs nailed it " stock bigger main jets, 122 & 125" and a#38 for the pilot.
    Pulling carbs apart over the course of 7 hrs. I am so slow and I am paranoid about every little thing. Reading and re-reading V4dreams online instructions. Just now am I actually pulling #4 off the rack. Only smoking gun is iffy mains across the board and a filthy #1 filter (not sure of the component name, pick below). Pulled slides and every other thing I can find except the "choke plunger??" on the carb body. Any reason I can't put the whole carb in the sonic bath with distilled water and dish soap? That combo seems to work well on all the parts I have removed and cleaned so far.
    The needle and boot look great and relatively new on #4 carb.

    For performance, any reason to change out stuff while I am here? I have read #40 instead of #38 for the pilot and 125 fronts, 127 rears mains.
    IMG_3132.JPG IMG_3132.JPG IMG_3139.JPG IMG_3140.JPG IMG_3143.JPG
     
  14. squirrelman

    squirrelman Member

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    soaking carbs in water can cause throttle shafts to seize up solid when stored for a while, best avoided, and water doesn't properly clean petroleum-based crud.

    gasoline on a toothbrush does a better job.

    sept 5, 2021 008.JPG
     
    Last edited: Nov 27, 2021 at 5:52 PM
  15. 50th VFR

    50th VFR New Member

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    Forget the Haynes manual, good but not perfect would be my assessment.

    Down load the much more extensive Honda Workshop Manual from Carl Salter (RC24) and read in conjunction for the Addendum ( Section 25) for the 88/89 model.
     
  16. Thumbs

    Thumbs Member

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    I’ve put #40 pilots in but as the plugs looked perfect I left the main jets alone, unless you’re going to dyno it then leave it alone
     
  17. raYzerman

    raYzerman Insider

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    Naptha/kerosene/mineral spirits good for greasy stuff too...... I usually use 50/50 water and Simple Green in the ultrasonic cleaner, along with a tablespoon or so of Dawn dishwashing soap.
     
  18. Captain 80s

    Captain 80s Member

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    I would go up on the pilots. Mains not likely critical, I agree with thumbs, but if it was my carbs with that exhaust (planning on a thru race can) and perhaps going to run a K&N, I would bump each one up a size. Plus if they are staggered sizes, you can just move 2 and only have to buy 2. I think that's a pretty safe move in my experience. .5mm shim under the needles wouldn't hurt either.

    I've done more than a few of these, but I also realize every bike and conditions can be different.

    Keep being methodical, when you get thru these carbs it is a big sense of accomplishment. And you realize, they're really not that hard.

    Good job.
     
    Last edited: Nov 28, 2021 at 7:38 AM
  19. RogueRC24

    RogueRC24 New Member

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    The bike already has a KN, that cleaned up real nice with a hand washing.
    The pilot screw (long needle tip with small spring, o-ring, and washer) on #4 was also at 4 turns out. We want those at 2-1/2 correct ? O-ring was early flat.
     
  20. Captain 80s

    Captain 80s Member

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    If somebody thought that the screw needed to be 4 turns out, I would up the pilot for sure. 1-3/4 to 2-1/2 is the sweet spot. Sometimes when the screws are at 4 turns, there isn't enough spring pressure to keep them from vibrating out and you find them in the V of the motor when it starts running really shitty. Seen it many times.
     
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