Fork Oil Weights
 

I recently changed the fork oils in my XR650R to 15 weight on the advice of a friend. I beleieve its normally 5W. As I am quite heavy at 110kg it has improved the feel and ride of the bike, although alot stiffer. My only concern is whether adding more dense oil will load other components of the bike or suspension past their limits. ie. have i made the suspension to stiff to absorb bumps etc before the rest of the bike.

Thanks

holy cow! 15W must jar your spine something rotten! I'm over 100kg and rode an XRR round an MX track without bottoming it. the suspension is awesome and I can't really imagine that it has improved it! I have an XRL an just upped it from 7W to 10W, but that's cos it was way too soft. if your XRR is too soft, what riding do you do?
to answer your question, you're right the energy gets transferred elsewhere. my guess it goes into you more than the bike so I wouldn't worry too much unless you have a big tank as the supports may not like the 50g decelerations! personally, I wouldn't want to ride such an overdamped bike too hard. what happens when you get off? does it take a while to come back up to full height? good luck

15W oil in the front fork will not provide optimal handling.

In general the XR650R suspension is an excellent package, superior to most other big 4 strokes. Most people that change their XR650R suspension seem to choose a heavier rear spring as the most useful suspension mod (the stock spring is ok up to 85kg or so of rider) and many have the forks re-valved for a less harsh response, but thinner oil worked for me. Some people uprate the front springs, but that is unlikely to be needed (unless you are over 100kg or ride SX)

The front damping on an XR650R is generally considered to be on the very firm side. I originally ran on fully soft damper settings with 5W and have now changed to 2.5W which suits me better. (big Acerbis tank, no luggage, 80kg).

Note that when I drained my fork oil at 1000 miles (for the 1st time) it was in extremely poor condition (grey/brown and lumpy - possibly behaving like a 15W at the time!). I have not heard of anyone that had good factory oil come out when they drained it, so this may explain why you didn't notice a big difference.

NB I have dented my front rim in a couple of places from riding hard on rocky trails, HD rims and spokes would be a nice addition on this bike :-)

Ian - I think the XRR front rim is similar to the XRL and Hagon´s were impressed with it when they straightened it for me. having met 2 italians who run 3bar/45psi, I now use higher front pressures to protect the rim and tube
Rich