1994 RVF400R Build Project

Discussion in 'Mechanics Garage' started by NorcalBoy, Nov 7, 2018.

  1. NorcalBoy

    NorcalBoy Member

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    Speaking of patience, I pinged Braketech about the Axis Iron rotors and they still haven't gotten the blanks back from the grinder....looking now like September, at the earliest. I am going to have the zen of a Buddhist monk by the time this ends. :Playball:
     
  2. Gator

    Gator Insider

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    Its funny, the longer the project takes the more jacked up you get when it's close to the finish line. That first ride is always fun.
     
  3. squirrelman

    squirrelman Member

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    i've always done that on all my Hondas as SOP, especially important after an oil change.
     
    Last edited: Jul 2, 2021
  4. Diving Pete

    Diving Pete Member

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    Sounds like a sensible idea to me. It looks as if COVID has really put everything back a year....
     
  5. NorcalBoy

    NorcalBoy Member

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    Went by the shop as soon as I flew into town this morning. The moto is broken in and it's done a couple dyno pulls to 14k RPM. It's looking like it needs some new needles for the carbs. The OEM needles I have, J8VA's, are the wrong taper and it's a tad too fat between 4.5k and 6.5 k. The initial numbers, with no tuning, are 68-69 hp. My boys are estimating mid to possible high 70's after tuning. Have an email into Rick Oliver in the UK to see if I can source some new needles. I hope he gets back to me soon. I'm looking to get a set of 8's - A's, B's, and C's, as well as, a full suite of 9's in the A, B, and C taper.
     
    Last edited: Jul 3, 2021
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  6. KarlR

    KarlR New Member

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    Wow, that is screaming.
    I understand the different jets and what they do, but I have no clue about the needles. What part of the fueling do they affect?
     
  7. NorcalBoy

    NorcalBoy Member

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    [​IMG]
     
  8. Jim McCulloch

    Jim McCulloch New Member

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    Wow you can see why they went to fuel injection now.

    That is some voodoo shit right there. One would need meticulous records to map all that out regarding what did/did not work.
     
  9. NorcalBoy

    NorcalBoy Member

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    I was able to source a replica HRC jet kit from Rick Oliver in the UK. He is going to be drop shipping the kit to my tuner. This kit was discontinued by Honda, but Rick has assembled all the pieces to put it together. There are a couple companies stateside showing the Honda part available, but they are asking between $250 and $350 for them, and I doubt they even have them. Rick has his kit available for $179 and I've worked a lot with Rick in the past, so I'm going with the guy I can trust.....Rick.

    NC35 HRC replica carburetor kit £130
    Equivalent to Honda part# 06160-NKA-900 and consists of -
    4 - J9MA needles
    4- J9MB needles
    4 - J9MC needles
    12 - Needle circlips
    4 - 0.5mm needle shims
    4 - Emulsion tubes
    4 - Slide springs
    2 - HRC replica 30mm velocity stacks

    I already have the needle shims in 0.5 and 1.00 mm, HRC springs, and replica stacks, so these will be extra stock. I'm hoping the rest will be enough to get the job done.
     
  10. NorcalBoy

    NorcalBoy Member

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    It's actually not that difficult and it's made a lot easier with the dyno having an exhaust sampling channel and sensor. By the charts, it was very obvious where the issue was. Getting the right pieces was/is the hardest part of it.
     
  11. Gator

    Gator Insider

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    What’s the average time to swap out carb components? Once you’ve done it a few times I imagine you’re pretty quick at it. How accessible are the carbs?
     
  12. Diving Pete

    Diving Pete Member

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    They are under the airbox - LOL

    Basically in exactly the same place as the VFR800
     
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  13. Diving Pete

    Diving Pete Member

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    It depends on how quick and dirty you want to do it & what job you need to do on the carbs. You don't have the tank connected as you are running a external one & no fairings are in the way, its just a matter of disconnect the fuel, undo the 4 cross heads (JIC 2) on the intake rubbers and lift off.
    However, most people will also disconnect the throttle cables using 2 x 10mm spanners, maybe the choke cable if connected (JIC 2) cross head, and also possibly the airbox - also if installed.
    Now I can't remember if you have to remove the airbox base to get to the top screw but that's only 8 x JIC 4 cross heads and lift off.
    Then its remove the 3 x JIC 2 crossheads per carb, slowly remove the top, ensuring the vacuum spring doesn't go into orbit, and then withdraw the vacuum assembly complete. Change what you need to then reassemble.

    Not difficult, and as long as you have newish 'lubed' intake rubbers fairly quick.

    To do the bottom of the carb (main & pilot Jets) is easier & doesn't involve airbox removal.
     
    Last edited: Jul 4, 2021
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  14. NorcalBoy

    NorcalBoy Member

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    I have no idea how long it takes, but the slides were already out of it when I arrived. If it was me, and everything was set up, maybe 30 mins to do all the bottom brass and prolly the same to do all 4 needles. I remove the rubber locators off of the insulators and index the clamps to make it easier to pull the carbs.

    It didn't look like they had disconnected anything, except the choke cable. Of course, the airbox and tank were removed, both easy tasks. I have a quick disconnect on the fuel line and the fairings aren't installed. I took it to them sans fairings, just the tank and the seat. It looked like they had been running it off an aux fuel bottle on the dyno.
     
    Last edited: Jul 4, 2021
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  15. Gator

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    Thanks for the info. The only bike I have left that has a carburetor is a Suzuki DR 650. I sold my Yamaha RD 350 a few years back. Both those bikes are pretty easy to work on the carbs.
     
  16. NorcalBoy

    NorcalBoy Member

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    No problem, thanks for the questions. I try to always reassemble things to make them easier to work on later. Building them on an assembly line and working on them later, are two completely different things. These V4's have a lot of things crammed into a very small space, so everything you can do to help yourself out is worth it.
     
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  17. Diving Pete

    Diving Pete Member

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    The indexing of the carb rubbers is almost essential to getting it back together quickly. I refit all cables before mounting as its just easier - although it is possible to do it on the bike. As mentioned there isn't much space & what you don't want to do is go backwards
     
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  18. KarlR

    KarlR New Member

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    Thanks for the diagram. Looks like the needles are the most important part of the tuneing.
     
  19. NorcalBoy

    NorcalBoy Member

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    They have the most effect in overall range. The issue with CV carbs is that the needles are typically not adjustable, they look like a nail. The new needles in the HRC replica kit have 2mm of up and down adjustment with moveable clips, so that is a positive benefit. Allows for finer adjustments, after that, it's shims to get it even closer. Most jetting info people have is from close to sea level, here in the pueblo it's 2650'. Once again, it's a science experiment and knowledge gathering quest.
     
  20. squirrelman

    squirrelman Member

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    too simplistic. other major factors are venturi size and main jet size.
     
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