Fitting a CBR600 rear shock to an NC30

[MexicanGringo]

I'd read some accounts on this forum of people fitting a cbr600 rear shock and it sounded like it would definitely fit, but i couldn't find any photos or dimensions, so the photos below have been labelled. My old shock is rather lumpy and one day whilst bouncing the bike it made a hissing noise like the gas was escaping, so id say this has to be a major improvement. A bit of permanent modifying is required to make it fit though...

First you need to get the old one off, support the bike through the frame to get the rear wheel off the ground, then release all the preload and there shouldn't be any compression on the upper bolt when you withdraw it. One of the lower rear swingarm linkage bolts also needs to be removed to give access to the bottom shock bolt.




The rear coil mounting needs to be ground off the subframe to make space for the reservoir, then a new system devised to hold the coil & wiring, not a big deal though. Since the upper bush of the cbr600 shock is 2.5mm thinner, you'l need a 1.25mm M10 washer on the nut side, one on the other side isn't required since the cap-head bolt sits in the bracket, not against it.



Then part of the seat tray plastic needs to be cut to make space for the reservoir. Im using a taller& thinner battery than the standard YTX9-BS, mine measures 75mm thick, the YTX is 85mm thick, more plastic will need to be removed for the YTX9 as the reservoir sticks quite far into the battery box.



Ride height is increased by 30mm on setting 4, which is a light setting, this even after my old shock was on near full preload. CBR600 shocks up to 2006 are suitable, having a clevis lower mounting, the newer ones have a bush so can't be used.

The rear suspension feels MUCH better now, the addition of compression damping makes a big difference to the feel as the old shock used to dive and just felt lumpy. The spring rate is 550 lb/in, almost certainly higher than the standard shock, but shouldn't pose any problems for either street or track riding.

Have a look at this site http://www.peterverdonedesigns.com/05shock.htm for a breakdown of the shock and other useful information. Hopefully this all helps someone improve their rear suspension... Although in hindsight maybe a gsxr shock would have been easier with no modyfying...

[Smev]

Good load of info there!

Its good to see what else will fit too.

Who is going to do a write up for the GSXR version then?!

[slo12]

hmmm, 550 sound like a pretty light spring. I'm only 150lbs, several bags of stones, and I run a 750 on the Penske shock.

Very good write up :)

[Drunkn Munky]

Just fitted one to my 35, only thing extra you need to do is shave a bit off the top mount of the shock to alow it to move in the bracket.

Its also worth noting that early models of the shock pictured have a longer res which wont fit as the shorter one touches the side panel as it is.

Not test rode mine yet but it seems ok

The GSXR shock is an easier fit (if thats possible ) but ive heard it needs a different spring otherwise its way out.

[MexicanGringo]

Just found yours in the exhaust thread.. It looks like you could have tailored the custom subframe to fit the reservoir if it didn't fit. Fortunately it just clears the standard frame by about 3-4mm. The battery is really the only issue with fitting this shock.. BTW the dimensions shown above are for a 2006 shock, later models may be different.

[Drunkn Munky]

The res clears the subframe no problem on mine, i had to loose the coil holder but that was going anyway. What i meant was that there are versions of the same shock fitted to mine (06 model) with a longer res which will hit the bodywork.

My standard battery still fits but that is going soon to be replaced with a swanky tiny race one

I havent touched any settings on mine yet but measured the sag and its bang on 10mm which is what i use on the road so im hoping the spring rate etc wont be too far out, time will tell.

Late R6 shocks look like there work well also and with less mods.

[jama5]

Interesting read, thanks!

[geebus]

Ooooo idea for my race bike project...anyone want a standard rear suspension with res? lol

[Drunkn Munky]

Just to add you will need a spring closer to 800-850lb if fitting this to a NC

[Cammo]

Both the 600rr and gixxer shocks have very similar spring rates (depends on year) - both are a bit lower than the stock nc spring rate (600rr & gixxer = 640ish lb/in). I think most peeps are using 750-850 lb/in springs on nc shocks.

You can check the spring rates of many models through racetech's site (nc's aren't listed):
http://old.racetech.com/evalving/menu/searchstreet.asp

In saying that though, I'm keen to fit a standard late model shock to my road nc over winter, it has to be an improvement in many areas over a 20+ year old shock that has never been serviced. I'll be keeping the standard spring in place, I think it will be fine for commuting use.

Nice write up!