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ZX400

Discussion in 'General' started by G Dawg, Feb 1, 2023.

  1. Kurlon

    Kurlon Well-Known Member

    Geometry rather than frame materials?
     
  2. Monsterdood

    Monsterdood Well-Known Member

    Engines 101, if you double the cylinders at a given displacement the bore and the stroke get smaller allowing you to turn more rpm. Power comes from air + fuel and if you pump more air at a higher rpm, you make more power. So a 400 twin makes around 50hp (maybe a tad more for full SBK builds or about 4/7th of a 700cc twin) and a 400cc 4-cylinder probably makes 70-80hp (about 2/3 of a 600cc).

    Off the factory floor, they all will make less with catalytic converters and rich fueling and all, but the basic idea is that a 4-cylinder and twin at the same displacement are not equals in any sense of the word. The little Kawi 4-cylinder would make a great stepping stone for most any racer, Jr or otherwise. I still think they would lap similar to MA spec twins, maybe 1-2 seconds slower once developed.
     
  3. noles19

    noles19 Well-Known Member

    I can't see the 400 doing 29s at Barber
     
  4. sbk1198

    sbk1198 Well-Known Member

    I don't see them being quite up there with the top MotoAmerica twins, but I do think they'll be up there with supersport level R7 builds, or any SV650 builds. Gonna be tough to get close to those top R7s and RS660s though...but I don't think that's the goal. I'm just curious to see what classes it'll be allowed to race in (while still being competitive), cuz as of right now there aren't many across the board in CCS, WERA, AHRMA, MotoAmerica, etc.

    Heard a rumor today, from a dealer, that supposedly Kawasaki is doing a limited release this year and dealers will only get 1 or 2....towards the end of the year! Hoping that's not true.
     
  5. Monsterdood

    Monsterdood Well-Known Member

    Looks like 400 twins do 35’s, so I would guess a nicely built 400 I-4 would be in the 32-33 range.
     
  6. DDK732

    DDK732 Well-Known Member

    I think the ZX4 built to the MA Twins rules would be competitive in that class. Very competitive.
     
  7. noles19

    noles19 Well-Known Member

    Well there is a problem with the class name for that bike :crackup:
     
    Once a Wanker.. likes this.
  8. DDK732

    DDK732 Well-Known Member

    Yeah but in this day and age of racing what does that matter??? Look at what Supersport has become! :D

    The ZX4 will race against those bikes at the club level though. F2, Lightweight SS/GP, etc.
     
    Once a Wanker.. and noles19 like this.
  9. noles19

    noles19 Well-Known Member

    I was thinking that as I typed it:crackup:
     
    Once a Wanker.. and DDK732 like this.
  10. noles19

    noles19 Well-Known Member

    I will say I am skeptical that it will be a popular bike for racing against twins competitively. The fastest people will be able to go faster than average twins racers but fast vs fast I don't see it.
    Also I think it'll be harder to get people to buy into and convert it to race against twins vs just buying a r7 or 660 especially with the power those are starting to make which doesn't seem common knowledge yet.
     
    Michael Hausknecht likes this.
  11. regularguy

    regularguy Always Krispy

    Dymags, a set of adjustable offset triples, aluminum subframe, and a big tank with a dry break. Perfect for LW endurance.
     
    Monsterdood and Once a Wanker.. like this.
  12. noles19

    noles19 Well-Known Member

    A man with a plan already
     
    Once a Wanker.. likes this.
  13. regularguy

    regularguy Always Krispy

    the 400 probably makes similar peak hp to the R7. Not even close to the 660 though.
     
    Once a Wanker.. likes this.
  14. noles19

    noles19 Well-Known Member

    Exactly
     
  15. DDK732

    DDK732 Well-Known Member

    All I can say is wait until Graves is done with their work. From what I’ve seen so far I’m very optimistic.
     
  16. younglion

    younglion Well-Known Member

    I thought we already knew that the North American 400's will be in the 56hp range vs the R7 at around 68-69hp - that's over a 20% difference in peka power and the 400 is at a MUCH bigger deficit where it counts - torque - almost 1/2 the amount of the R7 - the big equalizer will be the $3500 needed for the 400 to get uncorked.
     
  17. DDK732

    DDK732 Well-Known Member

    The 400 is also highly restricted due to where it makes peak power. Probably one of the most restricted production bikes I’ve seen. The percentage of power unlocked with just a flash is impressive.
     
    Once a Wanker.. and younglion like this.
  18. regularguy

    regularguy Always Krispy

    Good to know they restricted the bike with electronics and not with smaller cams etc.
     
    Once a Wanker.. likes this.
  19. Kurlon

    Kurlon Well-Known Member

    There is a slightly (like .1mm or something) larger crank for a couple regions where the bike has to be slightly higher displacement to be legal on highways/etc... :D
     
    Once a Wanker.. likes this.
  20. surfingsk8r

    surfingsk8r Well-Known Member

    So as a general question for those who may have experience with similarly constructed bikes (rc390 comes to mind) is it an issue having a one piece steel frame that incorporates what would be the subframe. My first thought would be that it might be more resistant to bending/damage being steel vs aluminum, but the thought that if you wadded it good enough it would mean a complete frame replacement kind of sucks. So I guess the question is am I right on my line of thinking or is there some normally accepted procedure for this etc.

    Honestly pretty interested in this bike as a step down from my current 600, but have reservations about the one piece frame.
     

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