Rear Shock

A buddy of mine has been trying to sell me a '999RS' shock for my 749R for months. Although the standard shock in the bike works well, I was aware the bike squats under hard acceleration. Since I didn't really need it and as the 749RS was taking up a fair bit of my time and money, I was in no hurry. 

Last week, he finally offered me a deal I couldn't refuse, so the shock came my way. 

These race shocks have separate circuits for high and low speed compression damping. Essentially, you can tune the suspension to work well with small bumps - race track - and larger bumps - potholes or larger ripples - without compromise.

Ohlins DU 46

The DU46 was used on the 998RS as well as the 999RS and 749RS (there are external differences between the 998RS and 999RS DU46 but the internals are largely the same). Additionally, the Superstock 999S used these shocks too, and this is where you need to take some care.

There are no visible differences between the S shock and the R and RS. However, the valving and the spring are different on the 999RS and the 749R/RS due to the linear rocker/linkage (the 999RS also uses a longer swing arm, so the valving on these shocks are subtly different again).

The spring used with a linear rocker also needs to be stronger than that used with a progressive rocker. The spring on my road R is rated at 120. The spring that came with this new shock was rated at 80. This warranted further investigation, so the unit was sent to an Ohlins tech who confirmed that the valving was for the progressive rate suspension. This shock was originally sold for a 999S or a 999R that had progressive rate suspension (I'm still not clear whether the 999R had progressive or linear rate suspension).

It is possible to use a progressive DU46 with a linear rocker, but the spring must be changed and as a result, rebound must be set almost to the limit. BTW, the two small holes at each of the mounting points are for the potentiometer mountings, which are used to monitor the chocks performance.

For my shock, £140 has bought the linear valve and the time to fit it. The shock will go back on the bike in a week or so. Can't wait!












pic shamelessly ripped from ebay - apologies!