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K1 GSXR750 engine swap

Discussion in 'Modifications and Projects' started by DarkHorse, Oct 9, 2009.

  1. Hey all,

    I've been looking at the possibility of avoiding shelling out for a top end rebuild on my 80,000km K1 750 by swapping the entire engine out for a fresher one.

    My question is: can anyone tell me what other years/models I could look at for the donor? I want to go either 750 or 1000, and I know that K1-3 were pretty much identical... but what about a newer model?

    I'm hoping to do the job myself, which means no frame mods, the mounts will have to be the same, and I'd like to do as little electrical butchery as possible - my concern with later models is that they would require an appropriate ECU, wiring loom etc etc etc which is getting a bit too complicated.

    I've posted the same question on gixxer.com before anyone bothers to suggest that! (Thanks for the thought though...) :wink:

    Any suggestions, advice, cautions etc appreciated! Cheers, DH.
  2. Whats wrong with yours? I would assume that at 80,000km, it shouldn't be shagged yet.
  3. Needs pistons and valves pulled out, checked, machined replaced, new rings, seals etc etc etc - basically top end needs rebuilding.

    Compression is low on one pot and it's going through oil at an alarming rate - just spitting it straight out the exhaust unburnt. Also running a bit lumpy.

    Got vague quotes of $3-4000 for the rebuild - reckon I can get a replacement for less than that, so I'm investigating.

    Well that's killed the sell it on NR option!
  4. I would think that the most important thing here is, are you
    looking at the bike as a "keeper" or not?

    If it's a keeper, have the re-build done and keep it for another 100,000

    If you're selling then a wrecker donor engine is the way to go.
  5. I'm with Hawklord on this one - whilst a replacement engine will most probably be cheaper, be aware that there is no guarantee that the new engine won't also need a rebuild in the near future! Make sure that you get some form of warranty if buying from a wrecker.

    Like Hawklord said, if the bike is a keeper, then it would be advisable to rebuild the existing engine or buy a replacement engine (possibly even a 1000cc) and have that rebuilt/reconditioned prior to installation. That way you have peace of mind that your beloved Gixxer is going to run at its optimum for many more years to come.

    The other option is could you perform some basic maintenance and tuning on your existing bike and then sell it in order to buy a newer model?



    "I feel the need.... the need for speed!"
  6. Thanks guys, that's pretty much the debate, and I'm not sure which way I want to go.

    This is my first 'real' (non learner) bike, and I have a strong sentimental attachment to it for that reason. It's a great bike in it's own right though - plenty of power, great predictable handling, not too uncomfortable for long stints etc. I have also spent a bit of time and money already on customising (https://netrider.net.au/forums/showthread.php?t=101361&highlight=Blinging+Zook) which I am certain not to recoup if I sell it.

    That said, it is getting on a bit, and has been well and truly left behind in the evolution of sports bikes - I've been watching the new Gixxers and ZX6R being released with serious envy for anyone who gets one...

    Weasel, I have thought about getting it serviced and tuned as nicely as possible (it felt great immediately after the last service not long ago) and flogging it without mentioning what I know about the condition of the motor, but I'm not sure I could do that to someone - we're talking about a couple of grand minimum to get it right, and I know I'd be seriously pissed if I found that out not long after buying.
  7. As depressing as it sounds, another option would be to part it out or sell it as a 'fixer'. Paying someone to do a $4000 rebuild would be almost what a working bike would be worth at 80,000km.

    Having said that, I don't reckon the GSXR750 is too far behind modern sports-bikes. It ticks most of the boxes and if you got it fixed, i'm sure it would provide you with a lot of enjoyment.
  8. Dark Horse,

    I can empathise with your predicament. I personally own a K2 GSX-R 600 which is also my first "big" bike. I personally love the styling of the K1 - K3 series, and the resemblance to the 500cc GP bikes of that era. Having said that, I love the look of the later model Gixxers, particularly those from the K6 onwards.

    I also agree with the last post - there really isn't much between your model and the latest sportsbikes, as it really does come down to the rider's ability.

    I guess it really comes down to your finances and the level of attachment to your bike. The fact that you've already started customising this bike could mean that it's a keeper???? By the way, I love your mods dude - you've inspired me to do some similar customisations to my own bike!

    Getting back to your original query - I have heard of others who have fitted later model engines to these bikes without too many dramas. In particular, I have heard that it's possible to fit a K4 - K5 750cc or 1000cc to your model without too many modifications required to the frame and chassis etc.

    I'm afraid I'm not sure whether anything later than a K5 engine will fit though.



    "I feel the need.... the need for speed!"