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NOTE - This was written a couple of months ago, and since then I had an accident that the bike was deemed a repairable write-off. So another thread will come in time documenting the resurrection rebuild.
Also, this kind of an "in memory" post, so forgive the rather descriptive wording.
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After over 90,000 kilometres of great rides, from commuting, road racing, touring up and down the East coast of Australia and even some off-roading; the clutch on my bike finally started to show signs of having lived a good life. Some regulars to this forum may know my bike has been an evolution over time - bought new in 2014 - with numerous iterations of modification. The last few versions saw it putting out low-to-mid 50s hp at the wheel, with much of that bump up in power coming from some custom ground cams.

With the need a new clutch looming on the horizon, opportunity arose to acquire a younger, second hand engine (4500 kms) for about the same price as it would've been to get the clutch sorted. Added to that, I was working with one of the other forum members @Oyabun regarding the camshafts whom found the intake profile was lacking in relation to the exhaust and sorted me out with a better matched custom grind of the intake to go in the replacement engine. While we were at it, made the decision to obtain a performance head, also prepped by him - ported, polished and decked.

I also acquired some other parts along the way for the engine swap, namely a set of 3d printed velocity stacks from CarbonSmith courtesy of @MraRacer#934. I re-modified the airbox lid to accept the larger inlet of an MWR air filter. And as just standard maintenance items for the age, I threw in new plugs, leads and coil packs, along with doing my own fuel injector cleaning. The existing ported & polished throttle bodies were carried over from the previous build. I additionally fitted a PLX SM-AFR wideband 02 sensor which enables me to do my own fuel map tuning. This new iteration came together during the covid lockdown in March, doing the engine swap and adding/updating the other parts at the same time.

So as it stands the engine performance mods:
  • Modified 'wide-mouth' airbox lid with MWR air filter
  • CarbonSmith Velocity Stacks
  • Ported and polished throttle bodies
  • Ported, polished and decked head
  • Custom reground Intake and Exhaust camshafts
  • match ported exhaust outlets
  • IXIL big-bore de-cat header
  • Yoshimura R-77 slip-on (baffle in)
  • Power Commander 5 with enabled 10,500 rpm limiter
  • DynoJet QuickShifter
  • PLX SM-AFR wideband 02

With these mods, it is sitting around the 60hp at the wheel category - almost 45% increase from stock (42 rwhp)
Last dyno run clocked it at 58.8hp, though the PC5 had some gremlins then and the map has also been revised since then, pending another run on the rollers.

All that power won't do a lot of good if the bike can't keep the tyres in contact with the road. The previous suspension mods remain mostly unchanged, albeit swapping the GSXR750 shock for a GSXR600 unit to get a slightly softer rated spring, and also because that old shock was in need of a service after all those miles, but was cheaper to just buy another one. I also swapped out the previous fork springs being Racetech 8.5N linear springs for 8.0N rated ones.

Suspension mods as it stands is:
  • GSXR 600 rear shock
  • Racetech 0.80kg/mm linear springs
  • Racetech Gold cartridge emulators
  • Steering Stabiliser
  • CB400 fork strut brace
  • pre-load adjusters
  • 25/75 blend of 10W and 15 W
  • tyres : Dunlop SportMax Q3+

For stopping power, it currently has Core Moto steel braided brake lines, Brembo sintered pads and a Nissin 14mm remote reservoir master cylinder (stock is 12.7mm). While I have been researching means to further improve stopping power with alternative calipers in the future, to date have only found that would necessitate a wheel swap too.

Other notable additions to the bike to make it a little more personal with the customisation, was a slap of paint on the knee panels and lower fairing as well as under the head light to tie in with the factory red/white/blue colour scheme. An R&G Tail Tidy (cut version) is fitted with a MotoDynamics LED taillight, along with secondary brake lights being integrated with the indicators. The tyre hugger (also partly painted) and Yoshimura exhaust hanger are items from a CBR250R. Headlights bulbs are Auxito 4500lm 6000K LEDs and the indicators are from ebay with the fronts wired up to enable daytime running lights like our USA brothers have. The dash has also been removed and different polarising film applied to invert the colour to white text on black background. Last year the ageing battery was also replaced with an SSB Lithium-ion one to aid with reducing weight. The double-bubble windscreen is from PowerBronze, while the mirrors, 1" riser clip-ons, adjustable levers, rearsets and frame sliders are all no name eBay specials.

To aid with driver feedback and control, it has a Starlane Engear gear indicator with shift light, and a Trail Tech TTO water temp gauge. I've also fitted a Speedo Healer V4 and a G2 Throttle Tamer, along with Ezi-Grip Pro tank traction pads. For navigation, when needed, the phone sits on a QuadLock mount and a 2-port USB socket is installed under the dash to provide power.
For data-logging AFRs from the PLX module, this has been wired up via the Power Commander 5 analogue input line and so a laptop attached to the PC5 running Dynojet's Power Core C3 tuning software allows data capture while riding for later analysis and producing my own fuel maps.

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So "what's been done to it" is covered, some might be interested to know how it goes... Well it's certainly a very different beast. The riding position and the way it handles is much more sports bike. The rear shock conversion raised the back end up ~13mm and the clip-ons design necessitated dropping the front in the t'tree by ~3mm; these have reduced its trail angle and track length, meaning it's a lot more eager to drop into corners and quicker to change direction. The fork upgrades in culmination with the rear shock and sticky tyres makes the bike grip the road like cat on carpet! The suspension change was by far the best upgrade for a very noticeable difference and highly recommend to anyone seeking to modify their bike, before even thinking about power mods.

Speaking of power though, one cannot skip past that the bike is now in another class with its output. In addition with the suspension changes, it battles with and in some instances outpaces higher classed bikes. It holds level and even outpaces many the touted 'big' bikes with the 0-100kph and holding them off till they come on song and do rocket off... But when you're on the street, the race is already won once we hit the 100. Although I don't tout this bike as being 'better' than the more expensive, higher hp bikes, or placing tickets on my own riding capability; I do think a culmination of factors does contribute to it being "the little one that could".

Through the journey of modification I found two main power restrictions with the bike. First was the catalytic converter, with one iteration I simply took the stock pipe to an exhaust shop for a cheap and simple cash job, getting them to cut out the cat and replace it with a length of pipe. The second iteration I replaced the header completely with the bigger bored no-cat IXIL unit. In both instances without the cat, the workable rev range increased, making it more usable from lower and singing stronger up high. The second and biggest increase in power was the cams and head work. Obviously this bike was designed for more commuter oriented riding and therefore the profiles were made for maximum efficiency. Getting a set of high-lift, longer duration cams one can expect at least 5hp increase at the wheels, and even more with additional accompanying mods. The cams combined with higher flowing head has raised the top end breathing significantly.

The mods to the engine have increased the power across the entire range, most noticeably in the 4000-7500 rpm, but the upper end also a big gain. The stock engine's power starts to slow from the high 7s with peak at 8500 then tapering off to its 9100 limit. Whereas my bike continues increasing strongly and only begins slowing at 9000 with peak at 9300 which continues almost flat to 10,000 then tapering off to its 10500 limit. When it sings, it really is quite a sweet sounding song ;)

That mid-range gain is reminiscent of the bigger bikes, where putting around is the ever so slightest twist of throttle. With more torque at 3000 rpm than peak torque of stock, it effortlessly rolls around in 6th at 60km/h. Needing less throttle opening to achieve torque equates to getting up to speed sooner and shifting earlier; resulting in even better fuel economy than stock!... Well, so long as you can resist temptation to twist that throttle for a grin :D

For fuel economy, talking full tank averages tracked on fuelly.com - previously with economy riding style it would return ~3.6L/100km [65 US mpg], whereas my best so far with the new mods has been 3.1L/100km [75 US mpg]. On the flip side however, when twisting that wrist, stock would vary very little from economy riding, like an additional 0.1-0.2L/100km... Now though, it does sucks it down strongly when riding hard, with the highest full tank average so far of 4.0L/100km [58 US mpg] and that was with only ~130km of hard riding, the rest of the tank commuting.

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I have enjoyed learning the new skills needed to execute ideas. It has had a positive impact on my persona where I know I lack self-confidence; but I persevered, be it to do something different, to learn something new, to save money by doing it myself, or to correct my own mistakes. In the process gaining confidence that I can achieve what goals I set myself, to not say "I can't" but that "I'll learn so I can".

For those curious of "worth" for the way I see comparison. I bought this bike brand new from the showroom floor for $7,400, as it stands in current form has ~$5,400 worth of parts, for a total of $12,800. The current power figure puts it in the same class as a Yamaha MT-07, Kawasaki Versys 650... Which coincidentally also sell brand new in the $12-14,000 range. My bike, with higher spec suspension and a more lively, essentially race spec engine, consistently outshines these other bikes. So for me, I see it as a worthy monetary decision; as not only do I now have a higher classed bike, but also gained greater mechanical and electrical knowledge along the journey of customisation.

So, it had only been a matter of months that I had gotten this bike to the point of being just the way I liked it, with aesthetics, ergonomics and mechanics all sorted. Then an unfortunate event happened; out riding on a day when I knew full well I was out of sorts and not in the frame of mind to be on two wheels. In a split-second I found myself sliding on the road with my bike ahead of me on its side heading towards a cliff. Thankfully the guard rail stopped it from going over the edge, but did make significant damage to the front-end of the bike. It was deemed a repairable write-off and with insurance payout in hand and the salvaged wreck back in my garage, the idea of resurrecting it into something different was instigated... Stay tuned for the next iteration of this bike ;)

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IMAGES
Good memories: The accident:

LINKS to modification write-ups:
Airbox mod - High-flow Intake Mod
Throttle bodies - Modified Throttle Bodies
Wideband o2 - Wideband o2 conversion
Master cylinder - Front brake Master Cylinder upgrade
Velocity stacks - Honda CBR 500 Riders Forum
Cams - Camshafts for the 500's
PAIR system blanking - share on exhaust changes
Temp gauge - Digital temperature meter
GSXR shock - numerous threads... use search
Daytime running lights - US running lights on non-US model
Aftermarket clip-ons reduce vibrations - How to eliminate vibrations with aftermarket clip-ons
Weight Reduction - Weight Reduction
Dash LCD -
 

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Glad you lived to tell the tale. Nice write-up. Keep us posted on your progress.
 

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Well what a fantastic job. My head is spinning after reading your adventure. You did good my friend. It's a little fire breather. Sorry to hear your piece of bad look, at least you are ok and I'm sure you will push the boundary's once more. These are figures most of is can only dream about, but it gives inspiration to us all and it was interesting that you found the exhaust a large limiting factor which is within reach for most people. Do you think the engine will last a few thousand miles what would be your guess. Ps how many miles between oil changes do you normally cover.
 

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Discussion Starter #4
... Do you think the engine will last a few thousand miles what would be your guess. Ps how many miles between oil changes do you normally cover.
Cheers :)
I remember reading an article when the bike was first released that Honda designed the engine for over 250,000km, so yeah I reckon with good maintenance that is achievable. I do 6K km oil & filter changes, plugs every 18K km.
Although the new engine has greater power potential, I don't abuse it. Even at 90K with the old engine, that thing was still kicking strongly and had been handed off to another to continue doing duties. They're a very well built engine.
 

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Thanks for the write up! You and Oyabun have been an inspiration. I initially bought my CBR as a cheap entry into the world of sportbikes having been a long time automotive enthusiast. I just had a baby and am looking at switching from IT to finance in order to get a better work life balance, once everything is stabilized I would really like to get Oyabun's head and cam package then have CJR reflash the ECU to match. Should be pretty fun after that. In the meantime I might port the throttle bodies since it's about to get cold around here and the bike will sit for a while.
 
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Sorry to hear about the accident and am really glad you’re ok. In the end, that’s what really matters.
I’m sure the next build will be even better. As mentioned by others, you have been a great inspiration to many of us who ended up building our little bikes into “little bikes that could”. You and Oyabun were the reason I did all the mods to mine. All my riding buddies just shook their heads when they saw me wrenching on that bike and thought it wouldn’t amount to much. After, most of them couldn’t keep up with it in the twisties. I do miss her but unfortunately with the COVID things whacking my income this year, I couldn’t have both and just couldn’t walk away from the deal I got on the GSXS. Looking forward to reading more about the new build. Be safe.

John
 

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Loved the write-up. Nice well-rounded work. Would be cool to see a dyno overlay of a stock bike vs yours. Sounds really impressive. One thing that would give me pause would be that with the stroke of 66.8mm, 10,500RPM gives a mean piston speed of 4600ft/min, 600ft/min over what I assume would be the design limit with a 9200RPM fuel cut.

Sorry about the wreck. That really sucks. The damage looks non-structural (so fairings, headlight plastics, maybe some wiring etc). If so it should be very fixable. Streetable afterwards? If not, surely a good track bike.
 

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Totally appreciate this post!

As a new rider and not having yet ridden my bike, due to be delivered shortly and having come from a fast4 hobbyist I can feel the level of dedication spent on getting her to this point. Looking forward to all the threads. Thanks for sharing and glad you made it through ok.
 

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Discussion Starter #10
To follow on from this one, here's the rebuild post detailing the rebuild to bring it back to life
 
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