Cat lugs on hills

[data89]

Arctic Cat 500LE green 2005. It lugs going up steep hills (of which there are a lot here in Panama). Sounds like it's not getting enough gas. Puts me at about 20KPH going uphill.

I Can't figure it out, I've had this problem for a couple of years now. There were times it went away, but now it's lugging uphill again. I have a new fuel pump, all new gas, air, vacuum lines, I cleaned the carburetor for the 2nd time, tried adjusting the air setting on the carb, now back to 2 1/4 turns out (never seems to make a difference changing it a 1/8 turn at a time).

It runs great on level or slight hill, and fantastic downhill. I'm thinking it's something in the gas tank, but if a slope causes something to clog the filter, why not downhill also? I've had this Cat for 8 years now, and it ran fantastic the first 5 or 6 years. I put what was supposed to be bad gas in (after the fact) at about that time and have had problems ever since. It's a lot of work to get at the tank, so I've put it off, trying to solve the problem in more obvious ways.

Any suggestions are greatly appreciated, thanks.

Larry

[davefrombc]

Just searched on your  Cat... In see it  is a CVT transmission;  and that  may be your problem . If it runs fine everywhere  except on the steeper  uphill runs , it  may  be  the clutches are not  shifting  down  properly . If the  motor  clutch doesn't open  and the  driven  one  close to effectively give  you a shift   down,  the motor cannot  rev up to  develop its  full   power ..  Check  to  make  sure  both clutches  open  and close properly  without  binding  or sticking.

[data89]

Dave, it sounds like a very astute answer. I'll check my manual and see if I can figure out how to do that. Meanwhile, is there any advice you can provide on how to do that? Also, if it's a clutching problem, wouldn't it do that going downhill or on the level too?

Edited January 7, 2017 by data89
extra thought

[davefrombc]

The  belt driven  CVT transmissions on some  quads is the same as the ones used on snowmobiles.  A friend  had  a similar  problem  on his machine  years  ago.. I  don't  know  if you've had a  look  at how those  CVT  transmissions work,  but  basically  they  work  by  varying the effective  sizes of  pulleys ..   At  idle  and  low  rpm  the motor  clutch  opens to  left the  belt  drop  into  the  pulley creating  a small   diameter  for it to  drive on. At the  same time  the  driven  pulley  closes  up  to  create  an effectively  large pulley. The   difference in pulley  diameters small  driver on the  motor   to large  driven  gives  you   "low"  gear .. as the  motor  revs  up , the  motor  pulley  closes,  making the  belt ride up to  a  larger  diameter , at the same time  the driven  pulley opens up to  create  a smaller  pulley  diameter, in effect  giving  a second  or  higher  gear ..  At  full motor  speed , the  motor  pulley  closes  to the  largest  effective diameter  for the motor and  driven   opens to   its smallest  effective diameter , so  that becomes  your  high  gear ..  If the  load pulls  the  motor  down , the dropping  rpm  opens the  clutch on the motor  while  the  other  clutch  opens,  effectively  lowering the  gear  so  the  motor  can rev up  to  produce its full power  again.  Not,  if the  motor  pulley   is  sticky  so  it  can't  open  properly  to allow  the  motor  to  rev up ,  it will  lug on you   as though  it was  a vehicle  tying to  pull  in too  high a gear.  You wouldn't  notice    the clutches  not    opening  and closing  properly  as  much on level  ground  or  going  downhill  because in those cases the motor  isn't loaded  as heavy to  move the  quad so  the  clutches would be staying  in higher effective  gears.  Its like  a   manual transmission  car.  You  can  start  out   fairly  easily  on the  flat or downhill ind  second or  high  gear,  but would have to  rev the motor  and slip the  clutch  much  more to  staret  out in  the same gear  heading uphill. 

Since the  clutches  are spring  loaded  and work  on a  centrifugal  system to  open  and  close against those  loading  springs, you  need to  be  cautious  when  you   go to disassemble them.  Those springs  could be  under  a  lot of tension.  You'd  need  the  manual  to  see  just  how to   service  those clutches . . I can't help  you  on that  since although the CVT   clutches  all  work  on the  same principle ,   there  are differences  in how the various manufacturers and  models  are all disassembled  and assembled.

[LT80]

I agree..Rear clutch torque spring got weak..

Edited January 7, 2017 by LT80

[data89]

Sounds like I need a shop manual.

[data89]

There must be a way to prove/disprove this. For instance, couldn't I be going in regular high gear on the level, at slow speed (considering the belt would be on the low speed auto), then make a turn and start uphill, still at low speed. Wouldn't that produce an answer?

Or, if I put the auto transmission in low gear, shouldn't I be able to accelerate up the hill without a problem?

[davefrombc]

With a CVT there is no  "low gear"  or  "high gear"  the clutches  act  as gears   by constantly varying the ratio  between them  depending on rpm  and torque  load.

 

[data89]

Okay, watched some u-tube videos on the clutch. Really pretty simple. The hardest would be getting parts shipped to Panama.

I have one more question not answered...my Cat (automatic with 4 wd) has a low speed and high speed shift. How does that work? Does the belt just stay at low speed position even while using higher RPMs? If so how? From what I saw the clutch is going to work the same. Am I actually shifting gears to achieve this?

[data89]

5 hours ago, davefrombc said:

With a CVT there is no  "low gear"  or  "high gear"  the clutches  act  as gears   by constantly varying the ratio  between them  depending on rpm  and torque  load.

 

And yet I have a low gear shift position that winds out at about 30 miles per hour, about 5000 rpm. What am I missing?

Okay...I ran it down the hill, turned around, started slow going up the hill now. With the shift in high, at about 17 miles per hour it bogged down, lack of power and the engine would have quit if I didn't slow to about 14 mph. I stopped, shifted into low gear. It went up the hill with no problem. Low gear tops out about 35 mph which is very high rpm, so I continued at about 30 mph and it didn't lack for power. I stopped, shifted into high gear and at about 17 mph it started bogging down again.

What is the clutch doing when in low gear? Why does it not have a problem in low gear?

[LT80]

When the rear spring is weak the belt pulls down in the rear clutch too fast. Fine for level sorta but when it should be squeezing the belt back out needing a lower gear ratio, it isn't. It's leaving it in "high gear" so to speak.

Now you put it in Low range and it's OK because the much lower internal gearing allows it to be fine for how the clutch is working.

[LT80]

http://www.offroaderie.com/OEMpartfinder.htm?aribrand=POL#/Arctic_Cat/2005_ATV_500_AUTOMATIC_TRANSMISSION_4X4_TRV_CAT_GREEN/TRANSMISSION_ASSEMBLY_[60169]/2|~81280/2|~81280|~0737-771

#7 is the spring needed.

Just a parts fiche,I wouldn't buy from them.  

Edited January 7, 2017 by LT80

[davefrombc]

1 hour ago, data89 said:

And yet I have a low gear shift position that winds out at about 30 miles per hour, about 5000 rpm. What am I missing?

Okay...I ran it down the hill, turned around, started slow going up the hill now. With the shift in high, at about 17 miles per hour it bogged down, lack of power and the engine would have quit if I didn't slow to about 14 mph. I stopped, shifted into low gear. It went up the hill with no problem. Low gear tops out about 35 mph which is very high rpm, so I continued at about 30 mph and it didn't lack for power. I stopped, shifted into high gear and at about 17 mph it started bogging down again.

What is the clutch doing when in low gear? Why does it not have a problem in low gear?

You  have a  dual range  (low/  high)  in your  quad  rather than  a single range as I had assumed from   earlier   posts..   The  clutches  act  as  a transmission,  the  range selector is what  chooses the speed and  power  range .  In  High range ,  your  quad will  go  its  maximum speed ,  in  low range  it   will  move the  slowest in really  rough going ,  and give the most  pulling  power.

[data89]

1 hour ago, LT80 said:

http://www.offroaderie.com/OEMpartfinder.htm?aribrand=POL#/Arctic_Cat/2005_ATV_500_AUTOMATIC_TRANSMISSION_4X4_TRV_CAT_GREEN/TRANSMISSION_ASSEMBLY_[60169]/2|~81280/2|~81280|~0737-771

#7 is the spring needed.

Just a parts fiche,I wouldn't buy from them.  

 Thanks for the reference though. I did find the spring at "gearhead.com" for $25.

[data89]

13 minutes ago, davefrombc said:

You  have a  dual range  (low/  high)  in your  quad  rather than  a single range as I had assumed from   earlier   posts..   The  clutches  act  as  a transmission,  the  range selector is what  chooses the speed and  power  range .  In  High range ,  your  quad will  go  its  maximum speed ,  in  low range  it   will  move the  slowest in really  rough going ,  and give the most  pulling  power.

So if I understand what you're saying...the 2 different ranges physically shift gears, but the clutch functions the same, only, because it's in low range, it has no need to move up/down to accommodate the faster speed as it has to in high range.

I think, in the next few days, I'll pull the cover off and take a look. I'll let you know what I find. Thanks again for all your expertise.

Larry

[LT80]

"it has no need to move up/down to accommodate the faster speed as it has to in high range."

No it still will move the same as in high. You just can't notice the spring problem in low range.

Yes you have a good top end in low. The bad spring has nothing to do with top end, it's pancaking nicely..LOL. The spring isn't allowing the rear clutch to close giving it low end.

Another thing that should be mentioned is that the rear clutch may be partially froze up and not sliding correct causing the same effect as a spring. When you tear it apart you should be able to work the rear clutch back and forth with both hands to inspect that aspect of it.

[davefrombc]

The two  ranges   physically   change  the  final  speed of the  quad ..the  clutches  determine  how  fast it  will  go  in  each range .. Tyhe  clutches  make  up  a  CVT  transmission ..

Continuously  Variable  Transmission..  The  motor  is allowed  to  run  at  a   constant  speed  set  my the throttle  while  the  clutches  move in and  out to  vary  the   power    delivered  to the  final  drive . You  can  have  high revs at  first  ( like a  standard transmission   in  first)  but  slow  movement ,  then  as  the quad  moves the same revs  will  give you  more speed  and the  clutches change  the effective  pulley  diameters  (  like  shifting a manual  transmission into  a higher  gear)

[data89]

I spent all afternoon just getting the foot support and foot brake off. Everything rusted tight. Needed some heat and had to hacksaw one bolt. But, all ready for tomorrow, to take the clutch cover off and see what it looks like.

[data89]

I got the clutch cover off and everything looks fine. I started the engine and revved it up...no hesitation, no problem, the belt goes up and down smoothly as it should. I cleaned the cover and put it back on. I'll try it again tomorrow, but expect the same lugging problem. Still seems like it's a gas/air problem. Any thoughts?

[davefrombc]

From  your description  of the problem   the only thing I  could  point to  was  a clutch problem.   I really  don't  think  you'd  be  able  to test the   clutches properly without  putting them  under load ..    Just  jacking it  up  and  running  it  unloaded  won't  show  up  many  problems that only occur when  pulling  hard. I'm  afraid  I  can't   offer  any suggestions  on fiddling  with the  fuel /  air  ratios to  get  more   power.  That is something you'd  have to  work  out  by trial  and error  on the settings .  a  little  adjustment  up  or  down  at  a time,  try,  readjust,  try  again  until  you  find  the  best  mix.

[data89]

1 minute ago, davefrombc said:

From  your description  of the problem   the only thing I  could  point to  was  a clutch problem.   I really  don't  think  you'd  be  able  to test the   clutches properly without  putting them  under load ..    Just  jacking it  up  and  running  it  unloaded  won't  show  up  many  problems that only occur when  pulling  hard. I'm  afraid  I  can't   offer  any suggestions  on fiddling  with the  fuel /  air  ratios to  get  more   power.  That is something you'd  have to  work  out  by trial  and error  on the settings .  a  little  adjustment  up  or  down  at  a time,  try,  readjust,  try  again  until  you  find  the  best  mix.

The only adjustment on the outside of the carb is the air setting. The manual does not say which way increases air or decreases. Do you know, if I turn the screw out, am I increasing air or decreasing air?

[davefrombc]

turning  out  ( counterclockwise )  opens the  jet.  If there  is only  one   adjustable  jet on the  carb , it is  likely  only the  idle  air  mix.

[LT80]

Time for a compression test.

Has the valves been adjusted lately?

[data89]

On 1/9/2017 at 7:57 PM, davefrombc said:

turning  out  ( counterclockwise )  opens the  jet.  If there  is only  one   adjustable  jet on the  carb , it is  likely  only the  idle  air  mix.

Thanks, I'll play with that for awhile. Long process, as I can only get at it with a short screwdriver when the exhaust pipe is cold.

[data89]

On 1/10/2017 at 10:26 AM, LT80 said:

Time for a compression test.

Has the valves been adjusted lately?

Never by me (8 years). Suckers are hard to get at, have to take the whole front off, plastic, racks, just to see the covers. And all bolts are rusted tight.

Edited January 11, 2017 by data89
another thought

[data89]

UPDATE: Problem solved. I decided I would start all over with the carb air adjust setting. Turned it all the way in then backed off according to the book 2 1/4 turns. I had originally assumed the problem to be that the carb needed more air, so I had been turning it out 1/8 turn at a test. WRONG. This time I started turning the screw in 1/4 turn (to 2 turns out from 2 1/4). It worked right off. All this time the carb was getting too much air in the mix. It works fine now, no lugging on hills any more.

The reason I kept thinking it was a "air problem" is because a few years back I had taken the snorkels off and immediately ran into a poor running situation like this where it was getting too much air. Then, however it didn't want to run well at any speed, so I rerouted the snorkels underneath the hood (out of the way now so I can carry a tray on the front) effectively restricting the air intake, and it worked fine after.

This new problem probably started with air leaks in the old gas and vent hoses and I had started compensating with other adjustments. Now, I have all new vent and gas hoses.

Thank you everyone for trying to help me, and you have given me more experience, especially in how the automatic shifting works.

Larry

[davefrombc]

Usually  when   adjusting  the screws on carbs  from  automobiles to  snowmobiles ,  ATVs and even  the  older lawn  mower  and  trimmers  ,the starting point  is  1 1/2  to  2  turns out  from  closed.. Glad  you  found the problem  and it was an  easy  fix.  Thanks for  letting us  know .