XR80R Rear Spring Upgrade

[Army_of_One]

I just purchased a 2003 XR80R for my kid to start riding.  I can't find the max recommended weight for this bike.  He's 130 lbs ish and I've been concerned about the rear spring needing to be stiffer.  I've been looking into an XR100R shock/damper setup, but they're hard to come by.  I did notice there is a parts number difference between the 98-00 and the 01-03 XR100R "Cushion Assembly."  The pre-01 shock absorber is .02 longer than the XR80R shock absorber.  The 01-03 XR100R is .18 longer than the XR80R shock.  If the BBR spring is advertised for 85-03, why can't the XR100R shock be used on the XR80R?  The spring stopper seat is identical between all three, so the diameter can't be much different, if any.  Has anyone tried this, or am I going to have to bite the bullet and try it?  Thank you for reading my rant. 

[socalxr]

XR100 shocks are plentiful on ebay.  CRF100 shocks, not so much.

[4strokeridertt]

A used shock may be completely beat already. This will cause worse problems.

[socalxr]

2 hours ago, 4strokeridertt said:

A used shock may be completely beat already. This will cause worse problems.

Maybe, but a heavier spring will only cause it to rebound faster.  Besides, every stock XR shock is junk already.  So for only $25 for a XR100, you might as well get a slightly stiffer one.    

[arthur6]

We have an XR80 here. Guys 300+ have ridden it no problem.

[socalxr]

1 hour ago, arthur6 said:

We have an XR80 here. Guys 300+ have ridden it no problem.

Ridden it around the street or taken it to a field track with jumps or trails???