The Contact Patch
by Todd Vosper
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Top Gun Motorcycles
Contact Patch
07/01/2008

This month Elden answers a "burning" question about oil consumption...

Q. My 1987 KLR650 has only 24,000 miles on the odometer but it is using lots of
oil, much of which is being blown out the vent. What’s my problem?

A. You probably have a combination of factors contributing to your oil consumption
problem, but we believe over-gearing to be the principal culprit. Over-gearing a
KLR650 up from stock 15/43 is a bad idea, but the 17/43 sprockets you are using are
off the end of the scale.

The KLR650, among other things, has a weak piston that sometimes breaks down
between the two top rings causing increased oil consumption (at a minimum). We
suspect this to be your basic problem. If not, consider a broken ring and/or warped
cylinder liner which is common in the pre-1996 models which have thinner liners.

Fixing the top end would be costly and still leave you with other potential problems
down below.  Pre-1989 KLR650s had weak crankcases in the transmission area and
pre-1996 models had bad clutch baskets and balancer mechanisms, among other
things.

The KLRs in our group at Top Gun have never had a piston or ring problem because
we use the best lubricants and never abuse the piston with over-gearing or excessive
revving.

My 20,000 mile 2005 KLR650 was traveling 7,500 miles per litre of the slippery stuff
when it was killed by a reckless teenager last September. My 2004 KLR650 which just
turned 8,000 miles is going over 8,000 miles per litre of Spectro Platinum 4, 15w-50.
Rod Morris’s 53,000 mile 1996 KLR650 gets almost 4,000 miles per litre.

The key is to never violate the following rules:

  1. Keep wind drag at a minimum by having a low wind shield (or no windshield,
    which is our preferred method) and using roundish soft bags on side racks
    carried close to the bike.
  2. Never over-gear by always matching final drive gearing to the conditions
    anticipated. I'm about 210lbs dressed and use the following gearing; 15/44 for
    long solo trips on open paved roads; 15/45 for solo trips on mountainous, two-
    lane, paved roads; 15/47 gearing when two-up with Pauline on paved mountain
    roads (she doesn’t like freeways). 15/47 gearing for most solo off-road and Baja
    riding, and 14/45 gearing for two-up off-road with Pauline.
  3. Except for short periods while passing etc., keep engine RPMs below 5,000
    especially when cruising long distances. Sustained higher RPMs will not only
    increase oil consumption but could lead to piston or balancer problems.

Properly set-up pre-2008 KLR650s are great multisurface motorcycles as long as you
understand their limitations. Abuse them with over-loading, over-revving, over-gearing,
over-boring or inferior lubrication and you can expect expensive trouble sooner than it
should normally occur.  
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