What The Heck Am I Doing Wrong?

[bmsgaffer 2,053]

This is all for an XI machine, thus the angled mule pulleys to change the belt for the front mount PTO.

[shallowwatersailor 3,214]

The 79365 is the single-stage snowthrower, and the 79366 is the two-stage snowblower.

[WNYPCRepair 1,923]

Ah, OK, I thought I got lucky and the older blowers would fit an xi series too.

[RMCIII 838]

Unfortunately the "XI" series attachments only fit "XI" tractors. That being said, I would guess you could modify an attachment to fit, but not without A LOT of modification. The "Attach-A-Matic" itself is slightly larger than even that of the 500 series tractors.

RMC

[WNYPCRepair 1,923]

Unfortunately the "XI" series attachments only fit "XI" tractors. That being said, I would guess you could modify an attachment to fit, but not without A LOT of modification. The "Attach-A-Matic" itself is slightly larger than even that of the 500 series tractors.

RMC

Yeah, I knew the decks were different, and assumed everything was, but then I( saw all of you talking about this blower and didn't realize you all had an xi. 

[shallowwatersailor 3,214]

The 79365 single-stage snowthrower (just like the 60" mower deck with a design includes rotating gage wheels and auxiliary wheel) is a different design for the 5xi than the 79360/79362 for the C-xxx/300/400/500. Not only is the drive and attachment different but the auger is as well with only a single idler pulley.

One of our members passed on to me the words of caution last year from a dealer about the 5xi snowthrower. They said to be cautious with engaging the drive as it has trouble taking the initial torque. I know I ran my 523Dxi at less than full throttle last Winter due to the additional torque it has over the gas engine versions. I had purchased a tach to install on the tractor (since then installed on my DC-105) so to arrive at a proper rpm for the engine but couldn't figure a decent mounting point. The issue is the rotational speed of the auger is high due to being a single stage.

[RMCIII 838]

I think this question may have been asked before, but it seems that the single stage on a "XI" machine turns faster than any other blower I have owned or seen in action. It appears to turn as fast as the engine rpms are turning, or possibly even faster. Just the air being forced out of the chute is enough to take a cap off if it is not on your head tight. Anyone know the actual rpm's the "XI" single stage spins at?

Rob

[doc724 925]

It is definitely NOT faster than engine RPM's.  It appears that the pulley on the blower jackshaft is about the same diameter same as the engine pulley, therefore speed reduction takes place in the chain drive.  I did not count the teeth on either the drive or auger sprockets, but it looks to be about 3:1 reduction (just by looking at the diameter).  It could be even 4:1.  So if the engine is turning at 3600 RPM, the auger is doing 900-1200 RPM.  This is probably no different than the speed of a single stage mounted to a 300/400/500 series tractor.  On the later machines, the drive and PTO pulley is about the same diameter and the chain provides the speed reduction.  Idler pulleys and idler sprockets are only there to keep tension and rotational direction and to optimize the "wrap" of the chain on the sprocket.  I am guessing that the higher torque and HP of the xi machines necessitates greater wrap of the chain around the auger lest the chain jump the teeth.  A bit of speculation on all this as I did not study the chain routing, count the teeth, or measure the pulleys.  Also, on the conventional machines, you can feather the PTO engagement, whereas on the xi, the electronic clutch goes from no engagement to full engagement in milliseconds, and yes, that torque gets transferred pretty quickly to the auger which has a lot of rotational inertia.  The result of all this is that while the belts may slip a bit, the chain can only stretch and stretch is what wears out the teeth on the sprockets.

[WNYPCRepair 1,923]

The 79365 single-stage snowthrower (just like the 60" mower deck with a design includes rotating gage wheels and auxiliary wheel) is a different design for the 5xi than the 79360/79362 for the C-xxx/300/400/500. Not only is the drive and attachment different but the auger is as well with only a single idler pulley.

One of our members passed on to me the words of caution last year from a dealer about the 5xi snowthrower. They said to be cautious with engaging the drive as it has trouble taking the initial torque. I know I ran my 523Dxi at less than full throttle last Winter due to the additional torque it has over the gas engine versions. I had purchased a tach to install on the tractor (since then installed on my DC-105) so to arrive at a proper rpm for the engine but couldn't figure a decent mounting point. The issue is the rotational speed of the auger is high due to being a single stage.

I was kind of surprised at the lack of gauges on the xi. I would have at least expected a tach. 
 

[shallowwatersailor 3,214]

I was told by a dealer that there was a Womens Advisory panel when the 5xi was being designed. The comparable John Deere models didn't have one either. It may have been a situation that the "Idiot" lights were sufficient considering that the tractors are designed to run at a wide open throttle setting.They do have a hour meter. Offering the diesel may have influenced to not install a tach as well if there wasn't a compatible tach. The dash would have needed to be larger as well.

[doc724 925]

OK, so I finally got around to counting the drive sprocket teeth and the auger sprocket teeth on the xi blower.  There are 12 drive sprocket teeth and 36 auger sprocket teeth for a 1:3 ratio.  Since the PTO pulley and the blower pulley are the same size, with an engine speed of 3600 RPM, the auger is spinning at 1200 rpm- Darn fast!  Also, the drive sprocket is welded to the jack shaft which makes it a costly replacement part. 

Last week I had my other tall shoot blower apart to replace one of the jack shaft bearings.  The drive sprocket is bigger on this model (14 teeth) and it is NOT welded on.  I did not count the auger teeth.

I guess the moral of this story is to make sure your chain is in good condition and not stretched.  A stretched chain will wear out the sprocket teeth and since the drive sprocket is getting more turns per engine rpm than the auger, it will be the first to wear out-a costly replacement proposition on an xi blower