Secondary clutch not back shifting under load?

[snorth88]

Hello all,
I've got a 97 Bigfoot that runs great except one problem I've been dealing with since I've owned it.
It loses rpms going climbing hills, not because it doesn't have enough power but because it will not back shift under load unless I stop.
For example I can climb any hill if I start slow at the bottom and just don't let the rpms climb, but if I was to open up the throttle enough to allow the belt to drop into the shelves I will eventually bog down. It's only if I stop, then the belt will come back up.
I've done all the servicing I can think of according to manual, new spring, new brass bushing,cleaned, lubricated as per manual.
Spring is in hole#2 and has been wound as per manual.
No other issues....that I know of.
I want this machine to maintain rpms going up hill at full throttle....the machines speed should slow but rpms basically should stay the same, just like a snowmobile does when climbing. I'm beginning to wonder if this is how these machines just are...but have nothing to compare it to.
Any solution is extremely appreciated
Thank you!!!!!

[SHOTGUN]

Do you have the right belt? If worn you bad you lose reduction. If it is too short as the primary closes with RPM the secondary will not be able to compensate for load. Still sounds like you have secondary issues. With you tranny in neutral rev your engine all the way up then let it come back to idle, you should see your clutches do a full sweep of open to closed. All I can think of for now, hope it helps. You are right that at any RPM the secondary should adjust for load.

[snorth88]

Thanks for your reply.
The belt is correct size and well within spec.
In neutral the secondary will open and belt will drop in and cycle back up as it should. This is what is baffling me.

[ARGOJIM]

You have the same issue many of us have, mine is a V2 and friends is a Bigfoot. The H trans is geared too high for hill climbing and even just a slight grade will affect it, but it will not stop it, merely just slow it. A bunch some times.
If you watch the clutch it is probably back shifting a bit but the engine cant spin it fast enough to make it climb.

Just for giggles and a short lesson, try and put a set of 22's on it on the same hill. It will still bog down some but should crest it faster, should this be the case the G gear set would be the way to go though it would slow your top end speed down. An M set of gears would work enough for a happy medium if you ran 22's and/or on open flat trails or dirt roads enough to justify the happy medium.

This applies to all pre 2003 Bigfoots and V2's

[snorth88]

Hello ArgoJim,

Thanks for your insight.
No offense but I can't see this as being the case for a few reasons ....
-I have driven the machine with the firewall off and can see how the clutch reacts. The belt will not come back up out of the sheves when its under load. unless I stop and rpms come down then it will.
-From a dead stop on a hill I can actually accelerate for a distance (even in high range)...until the belt bottoms in the sheves then it will eventually power out and lug the rest of the way.
- if I go up the hill slowly and don't allow the belt to drop (or upshift too much), by keeping rpms low I've got all kinds of climbing power. ( again even in HIGH range)
The H gear set in the transmission is fine if I can accelerate from a dead stop on a hill in HIGH range for a distance. (engine is not stock)
Gotta be a clutch design flaw or problem with the clutch because of either upshifting too quickly/to far, and/or for some reason not being able to backshift when under tension.
Thank-you

[ARGOJIM]

Ok if you feel it is in the clutches an easy try is a new spring to replace the nearly 20 year old spring, you could also try to put the spring in hole one.
I would still try 22's if you have them for a slight gearing change test.

[JoeMeg]

Could it have something to do with the springs in the primary? I thought they had influence on opening the primary when the secondary "senses" the torque requirement increasing.

[JohnF]

You said you have a new spring, cleaned, lubed; so probably not binding.

I'm going to guess you didn't wind far enough when you put it back together 'cause I heard that can happen.

Certainly try hole 1 as your description is classic "not enough spring" in the secondary.
Make sure your new spring is the right new spring.
You could also try hole 0 if it doesn't bind the spring.

There is no design flaw. What weights are in the drive pulley?

[SHOTGUN]

Quick test for you, crank up the secondary spring with as much tension as you can get, this will give you the most reduction and least speed. Also what do you have for an engine and primary, do you have the proper belt deflection, still kinda sounds like your belt is too short and your primary at full shift will force the secondary open too much. Just throwing out ideas, hope it can help.

[Coast2Coast]

I believe when I took my secondary apart a few months ago, I wound it up wrong at first. There are some youtube videos on this, check youtube, compare to your procedure. I agree with the others you will be looking for maximum spring tension to achieve slower acceleration shift and quicker backshift to improve hill climbing.

Also if you're running in the mountains at high altitudes argo sells lighter primary clutch weights that will help with that. The reduced power of the engine due to loss of air density would require lighter weights to allow the clutch to shift at a higher rpm to get closer to it's new torque curve.

I tried the adding a spacer to the primary spring trick, but I believe that served only to increase the engagement rpm of the primary clutch but didn't do a whole lot for the shifting part of the primary. It made it jerky and hard to control when doing slow work like loading it on a trailer or driving it onto a hoist, so I want to remove the spring spacer now so it will engage at the low rpms again.

An old worn out engine at normal altitudes might also benefit from lighter primary weights but I'm only guessing here . Of course that may be the highest priced 3 chunks of lead ever sold to any man anywhere, so being redneck as I am I'd just drill some out of each weight and make sure they're all equal weight. If that didn't work, I'd melt an old wheel weight into the drilled holes to replace the missing lead. This is something I might actually do myself if I feel like banging on my argo with wrenches and hammers again any time soon.

[ARGOJIM]

[QUOTE=JohnF;203246]You said you have a new spring, cleaned, lubed; so probably not binding.[QUOTE]

Crap missed that line somehow.

I'm going to guess you didn't wind far enough when you put it back together 'cause I heard that can happen.

Certainly try hole 1 as your description is classic "not enough spring" in the secondary.
Make sure your new spring is the right new spring.

Right on there.

[snorth88]

I really appreciate you all trying to solve this one for me and I will try all your suggestions.

I'm not sure what size weights are in the primary...but I did clean the primary, and did the "Rockdoc mod" and it does engage at a higher rpm.(not sure if I like that yet)
I am certain the secondary spring is the right one....but not 100% on the spring winding. The manual states" turning the movable
face counter clockwise 120 degrees, or one cam notch past the first cam shoe" which I thought I was doing...but If I can wind it further I will try.
The engine is a Vanguard 18 HP, 160 PSI comp on both cylinders & the new belt matches the number specified in the parts manual. ( I also tried my spare)
I know running 22's will affect ratio, and I have them for running tracks but its a Bigfoot and I want it to be able to work with the 25's , it's so much better for ground pressure and clearance.

Thanks I will report back!!

[snorth88]

quick update:
The clutch was wound correctly...I tried winding tighter but If you do it breaks the cam shoes off....
The new spring may have been the wrong one so I put another one in from a spare clutch I got out of an older machine...its blue in color, just like my old spring. The new spring I put in was black in color but the dealer told me they changed the new springs replacement to black in color.
I put the spring in the #1 hole this time.

Result: an Improvement for sure (better low end) but you still have to be careful not let rpms climb too high when going up hills, if that happens it will gear up and begin to slow down...the only way to get it to gear down is to backoff on the throttle considerably

Thanks