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the path to more grunt

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  • the path to more grunt

    hey all,

    i own a 99 kat 750cc

    only mod so far is a yoshi rs3 slip on.

    now im interested in getting a fair few more neddies from the beast. ive got 4 options im interested in. bear in mind im an engineer/fabricator by trade so i make whatever it is i do to my cars and bikes normally

    option 1- fabricate up a stainless steel header set up, running into the yoshi can, a k&N twin pod set up inside a custom airbox with ram-air pipework. and a re-jet of the carbs

    option 2- do the headers as above, replace the cams with gsx-r items (what year model should i use ) and also replace the carbs with gsxr items (again what year ) and fit up k&n's with the ram air set up.

    option 3- replace the whole engine with a larger one, like a gixxer 1100 or a 1200 bandit (i wish- but highly unfeasable due to australian design rules)

    the 4th option is the one im biased too, coming from a car background, ive built plenty of high hp custom turbo cars, my last car a 4 door 1400kg car ran 8.6 over the quater and yeilded 1080hp

    the 4th option would be for me to fabricate up a turbo setup on the 750 kat engine, obviously cooling would be an issue, so im wondering does the say... 1200 bandit oil cooler fit up the the 99 kat 750? if so, what year cooler is the one that fits?

    the plan would be to run a t25 garrent from a 1.8lt cyl car feeding into a mazda rx7 series 4 intercooler before reaching the set of carbs thats yet to be decided apon (gsxr1100 set maybe??)

    the work is easy done for myself, but im still fairly new to the bike world and the suzuki oil cooled engines, so im trying to gather up some knoledge of what works.

    any advice input or constructive critisim is more then welcome, i dont want knockers telling me it cant be done etc.. anything i learn im more then happy to put back into the forum in the form of tech articles too.


  • #2
    Wow, I think the Turbo setup would be the collest, but then again, the cooling issue would probably be one of your biggest challenges. With the turbo setup, are you looking to keep the fairings on and what not? I would think that there may be a way to mod the fairings to build your intercoller into, but there goes those chanllenges again. Good luck on what you decide. Oh, and that RAM air set up you are talking about sounds sweet too!!!
    -89 Gixxer 1100 Engine
    -Stage 3 Jet Kit / KNN Pod Filters
    -Ohlins Susupension
    -Various Other Mods


    • #3
      My first impressions were "OK, where is he going to take the RAM-inputs from, and how to do you insure no water is in it?" Then I realized you're down under and unless you're in the blue mountains, rain probably isn't a great issue. That still leaves a question about where to duct the RAM-air into the air filters (across the sides of the engine, under the fairing? modify the gas tank to fit it? etc...).

      I don't know the inspection requirements in Australia, but if you don't have annuals (or whatever interval), dropping a bigger engine in is easy as pie. If you do have inspections, and the inspectors aren't stupid or easily bribed, the question becomes what is it that they inspect for -- is it a case of as long as the exhaust gases are in order, the engine passes without closer eye-balling, or is it a case of fairings-off inspection of the engine? There is a manufacturer out there who makes over-bore kits for the motor, up to 813cc (3mm overbore), but personally I wouldn't want to shed that much of the block's mass away except for drag racing or a very cold weather climate (the 771cc - 1mm overbore would be probably be OK without major issues even in a hot weather environment given the right oil).

      As for the turbo, me thinks it to be a good concept for short, high-speed runs, but probably a poor idea for regular riding on an oil-air cooled engine. Two problems come to mind, the first you already covered (the added heat, which could easily push the temp of the oil over critical), and the second is whether the other engine subcomponents can handle an increased compression ratio (after all, we're talking about an engine that is designed for cost-effectiveness at a low price-point even new). Changing the concept to an electrically-driven supercharger instead of a turbo wouldn't address the compression issue either, although the packaging details might be more managable and the heat levels would probably be reduced by comparison to a turbo.

      The real question that comes to mind: would it be more cost effective to simply sell the bike and buy what you're desiring, as vs. to major mods? Odds are upgrading bikes instead of modding would be more cost-effective, but you wouldn't get the satisfaction of the tinker in the same sense, and I'm guessing that tinkering is a major part of the desirability at this stage.

      No simple answers here.
      Oh, except one:
      The oil coolers are different for each size engine, including the mounting tabs at the bottom of the oil cooler. You could probably fabricate a cooler with a larger capacity and higher surface-area to fit the stock tabs, which would be a good upgrade. Think square copper tubing turned 45 degrees (so two sides of the square face forward), brazed aluminum fins, larger total area and greater depth.

      Good Luck and keep us posted!
      =-= The CyberPoet
      Remember The CyberPoet


      • #4
        771 stage III.



        • #5
          trinc.. care to elaborate on that post? im not familur with a stage 3, and i presume the 771 is the 1mm overbore kit poet is talking about.

          im thinking a low boost (read: 5-7 psi) set up with a good intercooler and fueling, there shouldnt be any probs beisides the cooling of the engine, boost doesnt kill engines, rpm and detonation do.

          transplanting a larger engine into the frame, is frowned apon by authrities here, when transplanting the engine, they will look at the brakes (on the cards anyways) final drives and suspension is all capable of taking the larger engine... losts of hassels there, and even then, i could still be refused registration.

          then theres the fact the larger engine will upset the balance of the bike to some degree, also making it harder to flick around the hills.

          selling the bike for another one thats faster, ruins the fun for me.
          the kat is a comfy cruiser, i do a lot of miles on the bike (1000km a week) i cant ride sport bikes either due to my arms being rather short, it put a large strain on my lower back.

          so the kat stay's... im just going to modify it its pretty much aussie tradition.. modify it dont trade it.

          with the ram air... anything can be done, i'll have a look if its something i decide to do.



          • #6
            If you are interested I have a brand new set of Mega Cycle cams I have been trying to sell. Check this link:



            • #7
              Bandit 1200 is the best way to really bump the HP...a turbo just would require lots of work and money and the heat is a big issue...if you have lots of time and patience...then sure.

              the 1200 is pretty much a bolt in mod


              • #8
                Yeah I would go with the 1200. I looks just like the 750 except it is black. As a matter of fact I'm almost 100% sure that they don't even have the cc displacement on the left cylinder anymore. I know the 98+ 750's don't. I don't know how you guys do it down under but here in my state they title the bike off the VIN on the frame, so even though my 600 frame is going to have a fire breathing 771 in it I still pay insurance and fees on a 600. The other draw back is the 1200 doesn't have the electronic speedo pick up like the 600 and 750. Special$K$ is having a part made so that the electronic pick up will work. If you ask him I'm sure he will be more than happy to share his drawings and plans on how he is doing it.


                • #9
                  i presume you are talking about a in line turbo in the exhaust pipes that runs off the exhaust flow to help with the removal of gases faster though the pipe to allow the engine to rev faster and in turn make cleaner power can see a bit of heat problems but not a lot good luck my cousion is trying to gat one hooked up to his tubbed 1976 chev nova for this year has a super charger he whats to rebuild for next year always fun to fined some extra power
                  it would not be any fun if it was easy! but does it have to be this much fun!!
                  Give A Person Expetations To Live Up To Not to A Reputition To Live Down !!