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Discussion Starter #1
95 EXT EFI Mountain Cat 580

Primary had yellow/green when I bought it - bad bog in the midrange.

Primary fragged after 90 miles.

Replaced with new (used) primary that has the red spring.

Seems to be better, but still lacks power in the midrange unless you hammer it to WOT.

You can definitely feel the power come in, but it's like it immediately shifts out and the power is gone and it's all mushy.

Secondary issue? (yellow spring in there)

belt issue?

others?

Oh it burned an entire tank of gas (close to 10 gallons) in 40 miles so something aint right! My thought is the midrange bog is causing excessive throttle usage to keep up and therefore burning way too much gas.

Advice? Thanks!

PS - I don't have a manual - can anyone tell me what belt deflection should be and how to adjust? Also, what are engagment and shift out RPMs supposed to be? I'd love to know how to pull the secondary and try different spring holes too!
 

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Engagement should be around 4500 - 5000 and full shift around 8200 RPM. You can check the online microfische sites to find the stock clutch parts. The belt deflection should be about 1.25" with around 10 lbs of force applied and the belt should sit slightly above the outter edge of the secondary. That sled should probably get 90 - 100 miles on a tank, less in deep powder snow, so there are things wrong that may be other than the clutching. What do the plugs and piston wash look like? It sounds like it might be running too rich and not have a real cltuching problem. What is going to make the EFI run rich is the next question?
 

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Discussion Starter #3
this unit engages closer to 3000 - it looks like a red spring is stock in the primary (and that's what is in there now) and the yellow is right for the secondary. I'm not sure on the helixs though...

I'll check deflection this evening - is there an adjustment if it's out of spec? I think that it does sit out of the secondary just a bit.

Plugs seem to be ok - (I usually get some 70mph riding done on the way out though so they may be cleaning up before I look at them).

I haven't checked piston wash...

If you get on the throttle and bypass that cruising range of 30-60 mph the engine pulls and pulls - I guess that's why I think it's clutching/belt related...but I'm far from an expert!

What more can I look at?
 

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Discussion Starter #4
Update - belt is way loose

I'm sure I didn't get anywhere near 10 lbs and I had a good 2.5 - 3 inches...way loose.

I have been unable to locate a shop manual for this unit - could someone please give me the belt deflection procedure?

Also, I pulled the secondary - it has the stock spring and helix, but it was only in the second hole. The buttons looked to have a bit of wear on them. How much travel down the helix should I have? I had a good 5/8 of an inch that was not rubbed off - is it possible the secondary is not opening all the way?
 

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To measure the deflection you place a straight edge across the top of the belt and push down on the belt half way between the primary and secondary and measure the distance between the belt and the straight edge. That distance should be around 1.25", I believe. You adjust teh deflection by installing, or removing shims, between the fixed and movable sheave of the secondary clutch.

3000 is way to low for engagement. The engine will bog as it does not have enough torque at that low an RPM to work properly. Have you insatlled a new belt, and the correct belt? It should probably use the Cat 010 belt.

The plugs should be a nice tan colour and be dry. If the sled is only sluggish, or boggy in the mid range then maybe something in the clutches is binding. You may have to check the weights and rollers in the primary to make sure nothing is binding and same with the bushings in the secondary. The spring should be in the middle hole for stock calibration. Does the engine rev to peak RPM when you crack the throttle? From a dead stop it should rev to 8200 very quickly when you crack it wide open. have you replaced the battery and checked all the ground connections in the wiring harness. These old EFI systems are very sensitive to battery condition, and even a battery that tests OK for charge may not be liked by the ECU and the sled will not work properly.
 

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Discussion Starter #6
thanks for the info -

The belt is an 012 - according to browns it is the right belt. It is new. No detectable flat spots.

On primary engagment - I'm not sure what weights are in it - should I switch to yellow/green spring?

I've heard the battery and ground issue before. I want to tackle this one step at a time so first I'll fix the belt properly (deflection, alignment, and center to center) before messing with clutches. Then if I'm still bogging I'll work the clutches out. Then if I'm still bogging I'll check battery and fuel, grounds, pick up tubes, piston wash, plugs, TPS, stator, geez the list is endless at that point!

So on the belt issue - I separated the secondary and saw the shims you told me about. I'll remove one at a time (I think there were only two in there) and see where that puts the belt.

Can you by chance answer three questions for me?
  1. Can you tell me the spec for center to center distance and briefly how to measure? (edit - ok looks like this is supposed to be 12.2" - is it reasonable to just eyeball center of crank to center of jackshaft with all clutches off and measure by hand?)
  2. Is there a backwoods method of aligning the clutches without the fancy tool? (edit - finally saw how the tool works - looks fairly hard to do without the tool...I'm hoping to get deflection fixed first - if the bog improves I'll invest the money in the tool to get offset correct...just read too many posts and even heard tales from the dealer of completely unsolvable 580 efi bogs...guys that have replaced everything from wiring harnesses to ecus and from fuel pumps to stators...amazing that these are unfixable)
  3. If I run out of shims adjusting deflection and I have the correct belt what could that possibly mean? What can I do about it? Buy a shorter belt? Wider belt? Mess with shims at motor mounts?
Thanks a bunch for the help!
 

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Discussion Starter #7
OK - got the belt deflection adjusted - had to take two shims out to get it to sit up in the secondary and deflect around 1.25". Center to center looked ok with ol' Mark I Eyeball. I also replaced the secondary spring and buttons and put it back in the middle hole instead of the fourth hole.

Primary gave up about 100 miles and I got a used primary and put it on and I need some advice on set up.

The old (now broken) primary had yellow/green spring and A25 weights - I believe those are notched 49.5 gram weights.

The new (used) primary has what looks to be a redish spring and A54 weights - I believe those are un-notched 54.3 gram weights.

Looking at brown's it looks like my sled should have red spring and 49.5 gram weights stock.

With that info I've got a few questions for the clutch gurus...
  1. How should I set up this clutch?
  2. What benefits or detriments do I have by running the A54's with the red spring? Early engagement obviously, but what else?
  3. What kind of set up would the broken primary be using the yellow/green spring and A25 weights?
  4. Without buying parts it seems like I've got four combos to choose from...do I need to buy parts to set this up right?
  5. I'm trying to cure a mid-range bog. I've fixed a very loose belt and replaced a weak secondary spring. Compression is good (120's and both sides within a few psi of each other. Plugs are brown and piston wash actually is pretty black I could only just make out a small streak of wash near the intake - might be too lean or too much oil? Priot to this (haven't put miles on it since the work above) the sled has been burning a full tank in 40 miles - horrible mileage. Is there a clutch set up that would be better for the mid-range bog and fuel economy???
One final question - for testing purposes, how should the sled drive? If I'm cruising at 50mph should I be able to slowly ease the throttle and accelarate or should I have to aggressivly add throttle to get the RPMs to come up to peak - accelarate to where needed and then throttle back to cruise there? Also, should I be able to hold any speed without adding throttle?
 

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The 012 belt has the same dimensions as the 010, but is a softer compound. I suggest the next time you get a belt you get the 010 for longer belt life.

At this point you should set the clutches up to stock specs in order to get to stock RPM's and calibration.

Don't even think about using a broken spring.

The A25 weights are Comet weights, I believe. Have you checked the weight bushings, pivot and the rollers in the spider? Are they all in good shape and functioning properly?

Your wash sounds pretty good, but I don't see how you could have good wash and be burning that much fuel. If the engine is actually burning that much fuel then it should be smoking like a bugger, fouling plugs left, right and centre and the pistons should be washed clean.

The sled should accelerate as you want it to from cruising speed. If you want easy acceleration it should respond easily to gentle throttle movements, and if you want hard acceleration it should jump to peak RPM when you crack it WFO. It should hold a consistant speed if the snow conditions stay consistant, the load on the engine through the track and clutches.
 

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Discussion Starter #9
appreciate the fast replies and thanks for the belt tip!

At this point you should set the clutches up to stock specs in order to get to stock RPM's and calibration.[/b]
I'm no expert (in fact this is the first primary I've worked on) but the A25 weights appeared to be free of wear of other issues - I wiped off some gunk and they seem fine, so I replaced the A54's with the A25's and kept the red(ish) spring. It should be stock at this point. I don't know the condition of the red spring though. I'll look into getting a new one today. I'd have replaced the red primary spring, but dealer didn't have one.

Have you checked the weight bushings, pivot and the rollers in the spider?[/b]
The weight bushings (kind of like a little shim on each side of the weight?) were kind of corroded so I used the ones off the old broken primary - they were much better - I'll replace them after I buy some to be sure - this was tailgate mechanic hour though so I used what I had. (wasn't even planning on replacing weights till I got the cover off and found I could do it easily!)

The pivots and rollers in the spider are another story. Do you need special tools or experience to disasemble that? When I took the old broken clutch apart all I know is lots of pieces fell out (buttons, rollers, pivots, washers, etc) and I know an "oh $%&#" moment coming when I see one! Judging by the condition of the weight bolts and shims (bushings?) I would say the rest of the wear items should be replaced. Can I do that without special tools (and without experience) or do I need to take it in?

Your wash sounds pretty good, but I don't see how you could have good wash and be burning that much fuel. If the engine is actually burning that much fuel then it should be smoking like a bugger, fouling plugs left, right and centre and the pistons should be washed clean.[/b]
Like I said I haven't been able to put any miles on it since the belt was adjusted and the secondary spring was replaced and set to the middle hole, so maybe mileage has changed - but I don't think so.
 

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Do you have any gas oil showing up in the rear storage or coming out from under the seat? pm me let me know. thanks
 

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Discussion Starter #11
trunk stays dry - except for the broken "beverage" from the last ride

one very short leak on the back of the track, but it's a very small coolant drip from somewhere around the rear heat exchanger, no fuel or oil leaks detectable...

I'm going to try and top off both oil and fuel next time I get a chance to put some miles on it and then measure what it takes to top em both off and hopefully check if I'm near 50:1 on oil consumption and also get a current mpg estimate...

Clutching is the main issue though for now - I want to eliminate the clutch and belt mechanical issues from the bog/fuel mileage problem.

Will one clutching set up give me better fuel mileage?

Still looking for clutch answers from post #9 above - thanks for the help!
 

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The bushings I was refering to are the weight pivot bushings. These allow the weight to pivot smoothly, and straight on the pin. These are not thew washers that go on the sides of the weights.

I think most people will tell you that if the rollers on the spider are worn and not functioning properly you are better off to replace the clutch with a new one. The spider is installed with heavy duty thread locker and torqued to something like 110 ft lbs, and you need a spider tool to remove it. When a clutch comes apart at 8000 RPM it can be dangerous, so take care in making sure it gets back together properly. Do oyu have a clutch puller to remove the clutch from the crank? Take the clutch to someone who can evaluate the condition of the rollers and spider.

Clutching can effect fuel consumption by keeping the engine in less than optimum RPM range for the way you ride. However, I doubt poor clutching would reduce fuel milage by 60+%. The sled previously had a custom clutch set up for whatever reason the previous owner wanted. If you can't get to stock engagement and peak RPM's with the stock parts then you may have to consider that the primary spring may not be a Cat red spring.
 

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Discussion Starter #13
Good post - thanks.

Yep still trying to locate a new red primary spring.

Wow - prices of those rollers and bushing are outrageous! I definitely won't mess with the spider - at least not without the right tools. Probably will have that done at a shop over the summer.

Yep have a puller and am getting good at getting the primary off!

I'm going to play with the various parts I have tonight - also rough up the sheaves with some 240 grit paper, wire brush the belt sides, and I'll look for a 49* helix to expiriment with.

Hopefully I'll have made some progress...
 

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Discussion Starter #14
ok well I did quite a bit of swapping and testing...

stock set up sucked! (49.5 gram with red spring and yellow secondary spring in the middle hole) Don't know if it's due to the condition of the red spring (couldn't find one in town)

Then I tried the same thing with the secondary in the 4th hole. Not much different.

Then I tried the yellow green spring in the primary (again not a new spring).....I really thought this fixed it. I ran a half dozen or more test runs and didn't notice the bog...just about when I was going to pack it in it started bogging and then got as bad as before. One observation with this setup - the weights didn't seem to rest on the spider with the clutch fully open...with the clutch off if you flipped it end over end you could actually hear the weights clang into the spider when you flipped it upside down. Does the fact that the bog was gone and then came back scream "BELT"???? It seems to be in fine shape - I'm going to pick up a new one to be sure, but I just don't know...oh and I gues I'm going to buy an 020 belt - they tell me that the 012 (stock) is the same dimensions, but the 20 is a harder compound.

With the bog back I tried the 54 gram weights with the yellow/green primary spring. The bog was gone. I could cruise at any speed in the power band and also could accelerate gently from any speed - I could also accelerate aggressively from any speed. The top end RPMs were quite different though. It was running in the 7800 range when I pinned the throttle. Above say 50 mph - if you were just cruising and pinned it the RPMs would jump, but not the big jump that I was used to with the other set ups.

That's how I left it...one last ride this coming weekend and it's at least driveable. I'll mess it with again next season after I get a chance to tear into the chain case and count gear teeth...who knows, maybe someone geared it high and that's goofing up the clutching...Once I know what the gears are (and if I want them that way!) I'll get new primary springs and a set of weights smaller than these 54's (way too big judging by the low engagement and reduced top end rpms) and do some more tuning.

Regarding the fuel consumption - all of my testing ran about 35 miles - and once again it burned a tank of gas. Two theories going I guess - either it wasn't a good test because I had the bog for the vast majority of those miles... -OR- it's not clutching related! I repeatedly pulled plugs after running with the bog and they continue to look good. Piston wash is unchanged too - mostly black with just a hint of wash visible - guess I'm bringing lots of gas this weekend!
 

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It is the 010 that is the same dimension as the 012. The 020 is different, probably the same length, but different width.

Also, don't judge your fuel consumption by the fuel gauge in the filler cap. How much fuel did you put in the tank after your 35 miles? It will be good to check the gearing, but gearing should only effect the track speed and not the engine speed. The Yellow/Green spring is firmer than the red, so It should work with lighter weights, like the stock set up on my 94.

Bogging that only shows up after the engine gets fully heated up can be a sign of stator failure. If the bog disappears after the engine cools down a bit, then reappears a while later is classic stator problems.
 

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Discussion Starter #16
I hear you on the gas gauge, but I'm not really going by that. I haven't refilled it yet after that last ride, but will be filling it tomorrow. I've been watching fuel consumption closely and I know that it will take somewhere around 8 gallons.

ok - 010 belt, thanks!

As far as bogging after warm - I don't think thats what's happening. (not saying the stator isn't bad, but I'm saying I don't think the bog is engine temp related).

It bogged cold with some of the clutch setups and I ran it at high throttle for several miles with the 54g yellow/green set up in there now and it didn't bog.

History of the mid-range bog - I thought I'd fixed it several times. First ever ride, bogged bad right from the start of the ride. Went about 15 miles, changed the belt - bog went away. That was the first time I thought I fixed it. Rode it for a while (another 10-15 miles) no bog, but the belt had a couple hourglass spots and there was some vibration. Put a new belt on it - the 012 - I didn't put more than a mile or two on the test run with the new belt, but the bog and the vibration were gone.

Then took it on a long ride. Not long into the ride the bog started coming back. Changed back to the hourglassed belt and it was better (it was an ultimax belt - don't have the number handy). As the 90 mile ride progress the bog got worse. The next day a couple miles into a side trip the primary went south. Thoughts were that the degrading primary was the cause of the bog and that's why it progressivley got worse.

Then I replaced the primary with the used one - rode it for a few miles and thought the bog was gone (second time I thought I fixed it). The bog slowly crept back in...that's when I started messing with the clutch set up.

Then I was doing my test-n-tune described above with different clutch set ups and thought for the third time that I had fixed it, but it came back again.

Now I'm currently on the fourth time that I think I've fixed it. Each time I've thought that I've fixed it I've driven it far enough that the bog would have shown up before I made the change. Example - when doing the clutch tuning I ran it right off the trailer and it bogged. Probably only got a half mile in. Then I pulled the secondary and changed holes - bogged again right away and probably didn't put another mile on it. Then I pulled the primary and changed the spring. Had it off for longer than I had for the previous adjustment and it didn't bog. So I had a bog with a cold engine, but not a warm one - then it crept back in. And it didn't feel like an electrical "gone one second back the next" kind of thing - it felt like it was slowly coming back - I guess that's why I thought maybe it was the belt. And once it was back it stayed back - didn't matter cold warm etc...

At any rate I'm going to run it as is this weekend (I'll try once more to find a new red primary spring) and see if I have more strange recurrences....hopefully not - even with the clutch set up not perfect if I was able to remove the bog with clutching it should indicate that it's not a fuel or electrical issue...my theory anyway!
 

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Let us know what happens, but the longer this goes on the less I think it is a clutch realted issue. Another thing for you to check is the CDI. See if you can find one from a sled that runs normally and borrow it to test in yours. The CDI must be from another EFI sled. Clutches are pretty dumb pieces. There is only so much they can do and they don't tend to change from time to time without component failure. On the other hand, electrical components can fade in and out and act up under various, inconsistant conditions. Don't rule out the stator and find a known good CDI to test on your machine.
 

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Discussion Starter #19
never checked fuel pressure - if I find a gauge over the summer it'something I'll put on the list to check out!

Ran it over 50 miles this weekend (awesome check out the pic from Arctic Man) and no bog at all.

Exactly as I described last - top end rpms are down a bit with the too heavy weights (7800 instead of 8400) and the upshift when jamming the throttle wasn't as dramatic as it should be, but I kept up with the crowds so was happy!

I did still have the 4 miles per gallon problem - ugh - that hurts the wallet! I'm going to think about tearing the tank off this summer and checking for leaks.

Thanks for the help.

Oh and as for the bog - it has not come back since I put yellow/green and 54g weights in the primary. If it was a fuel/electrical problem am I correct in thinking that I could not have fixed it with any clutching set up? If that is true then I think that because I "fixed" it with clutching that proves it's not any other problem.
 

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Looks like a great day on the snow. Lets hope that the real problem is fixed and you can get it to work with lighter weights to get the RPM's up, so you don't lose any power, but you are pretty close. I don't know if lugging the engine with heavy weights will cause the excessive fuel consumption, but that has got to be the next problem to case down, because you shouldn't use that much fuel. Like you said, check for leaks. ;-) :thumbsup:
 
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