Snowmobile Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
28 Posts
Discussion Starter · #1 ·
So I'm not new here but lame in that I haven't been on since last winter... anyway hi!

Need some help please. I have a 1980 Yammy SRX440 sled, had it for years. Runs (for the most part) great. Haven't used it in years and my dad gave me this and our other sled to bring to my farm. Ran it last Dec 09, and got stuck in a snowdrift and overheated it due to an old tach/coolant belt my dad forgot to replace, and my being an idiot. result was i melted the spacers into the secondary sheave and froze the sheave.

cleaned that up, got new spacers and put on a tach/coolant belt and all seemed fine, however after the sled was running for 20-30min the belt would slip and eventually the sled would not move. gave up at end of season.

this the SOB still pull starts like a dream, runs great, sounds great, and it's still slipping. figured out my dad gave me 3 different sizes of belts that he must have not noticed he purchased all different sizes. in addition, it looks like while the sheave is fine (spacers that were replaced are still good), the clutch doesn't close enough to grab the belt. had some rust on it from age, and sprayed liquid wrench on it which got the sled to move about 100' forward, then the belt started slipping again. spray again with same result - grabs then slips.

here's my questions -
1) what IS the correct size belt or where can i find that info for this sled???? since obv if the belt is too big it WILL slip haha
2) other than lube the clutch and run the engine with the belt off to get the weights and parts in the clutch to loosen up and move better, what else can i do?

thanks!
 

·
Premium Member
Joined
·
5,737 Posts
if your using oem belts, look in your supply for one marked 89X. if you want a new one, look for an 8F2.

DO NOT run your sled without a belt to free up clutch parts and DO NOT lube the clutches!
 

·
Registered
Joined
·
28 Posts
Discussion Starter · #3 ·
if your using oem belts, look in your supply for one marked 89X. if you want a new one, look for an 8F2.

DO NOT run your sled without a belt to free up clutch parts and DO NOT lube the clutches!
okay wait why is that? if the clutch isn't grabbing all the way but the rest of the engine is fine what can i do to get it running better??? sorry if this seems stupid i honestly don't know,
 

·
Premium Member
Joined
·
5,737 Posts
your sleds engine is designed to perform at a given rpm with a load. if you remove the belt, there is no load and the engine will over rev and you could cause damage.

as for the lubrication idea, anything petroleum based on the sheaves will make the belt slip. anything of that nature inside the working components will collect belt dust and further restrict or wear the working components.

there should be lots of infoavailable on this forum pertaining to clutch cleaning. try a search. if you have any more questions or need some guidance on cleaning, ask away.
 

·
Registered
Joined
·
28 Posts
Discussion Starter · #5 ·
ok makes sense.

the clutch has been cleaned, though i can pull it off the sled and clean the clutch and clutch shaft again fully to be totally sure (it did sit since last season and prior to that for over 3 years w/o running).

other than the correct belt size and properly cleaning the clutch, i can't think of anything else it can be since the sled engine runs great (thank god), starts right up, and the only issue seems to be slippage. with the new spacers in the secondary sheave, and the secondary sheave functioning properly, and the clutch moveable by hand (when the engine is not running properly) i can't think of anything else it could be other than the clutch sticking from lack of use. right?

i mean the clutch is mechanical - as in due to rps, the weights/parts move causing centrifigual force to close the clutch and grab the belt. am i missing anything else?

thank you SO much! the sled's old - but the issue seems to be my fam letting it sit for several years w/o use and then the first use me not knowing it was missing the coolant/tach belt *sigh* and overheating it. as it is right now, with a 31 belt on it (can check exact model tomorrow - it's a delco) the clutch closes enough to grab for a few hundred feet, then slips and just melts the edge of the belt which obviously i know to stop running the sled since i don't want to burn through belts or mess up the parts with flying melted rubber.

thanks again!
 

·
Premium Member
Joined
·
5,737 Posts
sounds like your clutch alignment is off or the secondary isnt able to move freely on the jackshaft.

or

by spacers are you referring to ramp buttons? would have either been black plastic or even whitish? perhaps the helix wasnt properly wound and the secondary is upshifting too quickly and not backshifting.

which clutch are you referring to that "closes enough to grab the belt" the one attached to the engine or the other one?
 

·
Registered
Joined
·
28 Posts
Discussion Starter · #8 ·
spaces - small triangular-ish white pieces that space out the spring and secondary sheave assembly.

clutch - referring to the primary sheave clutch attached to the engine.

so in this case, the secondary sheave has been fully disassembled, cleaned, spring tuned (adjusted for heavier snow conditions as that's what we have here now), and put back on.

the primary sheave and clutch are what closes on the belt *almost* all the way, grabs for a few hundred feet, then the belt slips. this causes the belt to melt on the edges since the clutch is closing enough to touch the belt but not enough to grab properly.

in this case (and i believe i am using proper terminology based on my parts manuals) secondary sheave is the big aluminum plate assembly that has the spring to adjust the grab on the belt for slush or snow seen here:

primary sheave


secondary sheave


the secondary sheave spacers (item #3) melted and were replaced last year.
spring item #18 was set for slush as opposed to light snow for more aggressive grab on the belt as of last year
items #1,2,12,13, and 7 were all cleaned with a special non petroleoum non silicone powder (i think that was what it was called) when off the engine and later reassembled.

after the fixing of the secondary sheave last year, the sled would run for about 10 min or so and then start to slip. never figured it out. sled sat for summer. this week, started sled up no issues, and it ran as described above.

when running the engine with the hood open to see what is happening, the primary sheave (which i referred to as clutch) was closing on the belt enough to touch the edges of the belt but not fully engage the track. when sprayed with rust buster, it engaged the track for a few hundred feet at best, then started to slip. part #2 and 4 of the primary sheave set had visible rust that the rust buster removed. i did NOT use WD-40 as i know that is BAD bad bad for engines.

my thought was the primary sheave needs to be pulled off and cleaned again as when the engine is run with the hood up, that is the part that is touching without grabbing the belt causing the melting damage but i'm not 100% sure.

thanks again!!!!!!
 

·
Registered
Joined
·
28 Posts
Discussion Starter · #9 ·
ok going to see about cleaning the primary sheave (clutch) since that seems to be the issue. it is NOT closing all the way. could be due to rust, will check the spring while i'm at it, etc. i did find all the old manuals on the sled so that's a big help too. will keep everyone posted and thanks for the help!
 

·
Premium Member
Joined
·
5,737 Posts
from your description take a close look at the bushing located on the movable sheave as well as the bushings on the spider tips. it sounds as though the sheave is binding on the shaft, perhaps from a bad bushing.
 

·
Registered
Joined
·
28 Posts
Discussion Starter · #11 ·
parts #3, #19, and #9 in the primary sheave (top) diagram right?
THANK YOU! and that makes total sense. i'm going to try to pull it apart this weekend and see.
 

·
Premium Member
Joined
·
5,737 Posts
i should have looked at that first. makes it easy.

i was referring to #3 and #7 for starting points as these will make the clutch bind if they are worn out. #19 can contribute as well. #9 are the rollers and #24 are the weights. they need to be inspected as well but usually contribute to poor performance vs binding.

you are completely on the right track!
 
1 - 12 of 12 Posts
Top