Longer stacks from 90 and 91 model on a 93

Discussion in '3rd & 4th Generation 1990-1997' started by jethro, Oct 6, 2020.

  1. jethro

    jethro New Member

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    Has anyone played around with the longer stacks from the early vfr on the later 92 or 93. I would like to do this to see what if any difference there is. Another bike with this mod gave better mileage. I would like the torque and hp where I can use it. May not be noticeable, but I would like to do it to see. Anyone got a set for me to buy and try?
     
  2. squirrelman

    squirrelman Member

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    what you gain at one rpm might be lost at another. some chevy race engines used 4 short and 4 longer stacks to spread the boost.
     
  3. jethro

    jethro New Member

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    That's why I said I would rather have it lower where I can use it. I rarely ride around at redline and if I got a little bit better mileage it would be an added plus. I have seen the dyno graphs on a Hawk gt forum and putting a longer one on the front cyl. to match the long one on the rear cyl. netted hp ad torque down in the lower rpm's. That's what I want.
     
  4. squirrelman

    squirrelman Member

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    are you sure stock hawks have air funnels ? :rolleyes: i doubt it and have had 4 hawks over the years. alot of riders use pod filters obviously without stacks.

    pretty sure longer stacks boost low end.
     
    Last edited: Oct 6, 2020
  5. Terry Smith

    Terry Smith Member

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    My ST1100 had HUGE inlet stacks; actually they look like ear trumpets for the hard of hearing. Those bikes have monster low end torque but don't care to be revved out.
    P0002711w.jpg
     
  6. jethro

    jethro New Member

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    A number of the threads talked about the rear cyl. having a short stack and the front cyl. a long one, or vice versa, I can't remember right now which was which. I would think they were talking about the stock airbox. I saw the dyno graph where he replaced the one on the rear cyl. with a long one to match the front. Definite increase low to mid.
     
  7. jethro

    jethro New Member

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    That ST1100 airbox looks like half of the M5 airbox circa 2000.
     
  8. ridervfr

    ridervfr Member

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    Geez, those ST carbs are hideous - 3rd Gen VFR carbs, you could use as a paper weight on your desk (if your one of those white collar guys) and people would be envious of them. I would think tinkering with those velocity stacks would be a bad move, (that is just me though.) I know that Yoshimura had different length stacks to their old air/oil cooled slab bikes of yore, they were colour coded too.

    I had the misfortune of owning a NT650 - Gawd I was so glad to sell it to an idiot in Brooklyn! That bike I ran with out the top of the air box and remember loud intake honk and the obnoxious 2 bros exhaust. Sorry Squirrel, it was a turd - both of my EX500s would run circles around it! xxx
     
  9. jethro

    jethro New Member

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    I don't see any downside as the only reason for the shorter stacks was to up the hp total up top. They will be a drop in replacement.

    I have to agree with you on the 650 hawk. I raced a Vision for a number of years and the Hawks were a rolling roadblock unless they were built, but then the cranks broke. Had lots of good races with EX 500's and FZR400's.
     
  10. Captain 80s

    Captain 80s Member

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    I just bought a Hawk. But I didn't buy it for horsepower (obviously). Gonna put 95 VFR front end on it and rear wheel. It's a project bike to just bop around on and look good next to my CB-1.

    There was a guy who raced a Vision in my class (Lightweight GP). He was always working on it. I remember him also having issues with the chain over the swingarm pivot after raising the rear to try and make it turn. Beat him up, along with EX's, Hurricanes, FZR400/600 and a RZ500 on my 86 VF500F.

    Also had some sessions with Mike Velasco on his heavily modded NT650.
     
  11. jethro

    jethro New Member

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    Would the guy with the Vision happened to have been John Clemons?. I don't think he chain drove his bike as the Vision was shaft drive. He later had a chain drive Vision motor in an FZR400 frame and running gear.
     
  12. Captain 80s

    Captain 80s Member

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    That sounds like the bike, but is not the name of who raced it at the time. And now I remember it was because of how the engine was mounted in his bike.
     
  13. ridervfr

    ridervfr Member

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    I remember Mike V. Have seen touring Visions with some strange Buck Rodgers fairings along with the odd Radian of yore. Fit and finish on Hawk runs circles around EXs - but for ease of maintenance and just general great design, can't beat the Ninja500. I had the carburetors off my Hawk a gazillion times and never got the bike running to my liking, I think there was a black box issue or maybe a pulse generator problem - I needed a parts bike that became available years after I got out of that crate.

    Love the CB1 - its a 400cc gear drive cam bike right? I was in Tokyo when they came out, used to see blue and white ones all over.
     
  14. Captain 80s

    Captain 80s Member

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    Yep. Only Gear Driven in-line 4 released in the States by Honda.

    [​IMG]

    This pic doesn't really do it justice. Frame off resto of a totalled bike. 1994 VFR red with a little extra gold flake. Stock headers mated to a CBR-F2 Yosh. Fucking loud. I have a full Sudco for it that I am going to put back on. Fucking loud. Built it for my wife.
     
  15. ridervfr

    ridervfr Member

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    There is a video floating around where someone from Russia riding like a maniac in the city on that bike. Cool ride, I would steal it back from the "Little Missus" thats just me though. Side bar: I got roofers on my roof doing work and my daughter is asking me if she can put make-up on me. Really? jeez
     
  16. Captain 80s

    Captain 80s Member

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    "Built it for the wife" is one of my best moves.
     
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  17. jethro

    jethro New Member

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    Well, back on subject. Does anyone have some of the early longer stacks they want to sell?
     
  18. NorcalBoy

    NorcalBoy Member

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    Go Here: http://www.factorypro.com/

    1.) In the header of the home page, click Product Support
    2.) When the Page opens, click on Motorcycle Tuning Tech
    3.)When the list opens, toggle down to the "V" section and read the first three articles. This will give you a better understanding of what you are dealing with. It will allow you to make a more informed decision.

    You aren't getting the meat and potatoes you need in your tech diet from this thread. Marc Salvisberg knows his shit.
     
  19. ridervfr

    ridervfr Member

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    Always dealt with these guys, super knowledgeable staff and nice fellows.
     
  20. jethro

    jethro New Member

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    I was hoping VFR was under the v section.
     
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