98 Grizzly 600 runs smooth but slow...

[naveman]

I've got a 98 grizzly 600.  It starts fine, idles and revs  smooth up to about 3500 rpm.  It's got enough torque to grind the tires into powder if you hold the front brake but only drives about 10 mph...

I've taken the CV apart, cleaned out the old grease, regreased it with Yamalube and everything moves freely.  However, when it revs up the cones do not move as far as it looks like they should...  Any ideas would greatly appreciated.

[davefrombc]

If  the  motor will  rev up  ok ,  I'd suggest  blocking the  quad up  with  back wheels  off the  ground..  Make  sure it  can't  fall off the  blocking  and can't move.  With the cover  off  the  CVT so  you  can see  what's happening ,   rev the  motor  up  and watch the  clutches.. The  motor  clutch  should close  until the belt  is  at the top  of the groove  and the driven  should  open  until  the  belt  is  almost   down to the bottom. . Without  a  load  on the   tires ,  it  may  not  open  all  the  way since  opening  and closing  of the  clutches  is  determined  by the  load  on the  system  as well l as the  RPM.  The  motor  should rev well  over 3500...  should  go to  around  6000 - 8000.

Have  you also  checked to be  sure you don't have a  brake dragging ? The  tires  should  turn  fairly  easily  when  off the ground. There  will be  some  resistance  from the  drive train , but  it  should  not  be  difficult to  turn the  tires

[naveman]

When I removed the CV to clean and inspect I did exactly what you recommend.  When I reassembled it I left the cover off, jacked it up and started it up.  Everything turns as freely as it should but the drive clutch (cones) do not close far enough when revved up; there is still space for the belt to ride up higher on the cones.  When I had it apart I could not find anything that would cause it to hang up so I'm kind of at a loss.  I might take it apart again just to check...  I also need to poke around Google and figure out how to hook up a tach to see how high the engine is actually revving, see if that's right.

[davefrombc]

Did you  check to  see  if the  driven  clutch is free to  open  up?..  If  it  is  sticking   it can prevent the  drive clutch  from  closing all the  way.

You  can  get   tachs  that work  on a  optical  system. Put  a  reflective  mark on  a rotating  pulley ,  clutch   or  whatever  and the  hand held  optical  tach reads  the  reflections as  pulses to  calculate  rpm

Search on  "hand  held optical  tachometer"  or  "laser  photo tachometer"  

[naveman]

Tachometer reads 4000 rpm max.  I took the side cover off and removed the drive belt.  No drag on the driven pully at all and it opens easily enough.  However, the wet clutch is pretty well toasted; it's worn down to about half the minimum spec and the drum was obviously hot and is worn on the friction surface.  I wonder if there might be an equilebrium where the CVT ratio changes to the point where the wet clutch can't turn it (because it's toast).  If the drive belt is stretched it would make it worse, ride higher on the primary drive.

So I've ordered the wet clutch assembly and a new belt.  But since I live in Papua New Guinea and the parts are coming via sea freight it will probably be November before I can install them.  Either way these parts need to be replaced; hopefully it solves the problem.  Thanks for your help!

[Ajmboy]

On 6/27/2017 at 8:09 PM, naveman said:

But since I live in Papua New Guinea and the parts are coming via sea freight it will probably be November before I can install them.

WOW! Pretty cool. Post some pics when you get a chance. I'm sure the riding is beautiful.