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Discussion Starter · #1 ·
So I picked up this HR21. Seems to work pretty well, but I cant get the "3- Speed" shifter to do much of anything. I bought it from a sweet little old lady who said she always found that Speed-1 was more than fast enough for her, so she never used the other speeds. In my first use, seemed too slow for me, but speed control very stubborn to move- not surprising considering that it had not been used in a couple decades. So I lubed the cable, still really stiff and not "shifting". Then removed the drive belt cover to see generally what was up at the business end of it. Got the cable action loosened up enough now that it seems to do all it was ever meant to do, but surprised to find that all the speed control does is to adjust tension on the drive belt. Wondering: how could tightening the belt affect speed, unless the theory is to allow the belt to slip in the lower speeds so that it’s basically just getting less traction on the pulleys? Could that be? Am I missing something?
 

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Echoman or ShawnLB (and any other snowmobile folks)--Take a look at the left photo.

Looks to me to be very similar to the clutch setup on a snowmobile. As you tighten up the belt, it pulls it into the pulley on the right further, in essence making it a smaller diameter, thus changing the ratio. The pulley on the left looks to be a 2 pc setup, with that spring on the top.
 

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Very well could act that way. Not too sure with that set up. Never seen one before. Maybe the top pully sheve is stuct and not riding freely on the spring loaded shaft.?
 

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Lawn-Boy fan
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Echoman or ShawnLB (and any other snowmobile folks)--Take a look at the left photo.

Looks to me to be very similar to the clutch setup on a snowmobile. As you tighten up the belt, it pulls it into the pulley on the right further, in essence making it a smaller diameter, thus changing the ratio. The pulley on the left looks to be a 2 pc setup, with that spring on the top.

I agree. It should operate similar to a gas powered scooter or John Deere gator and all the other vehicles that change transmission speed automatically without any actual gears.

Echoman is probably right. The pully with the spring is probably seazed onto the shaft. Try taking it apart and freeing it up. You may have to play with the tension of the spring on the pully to get the tension right though.


On this link is a picture of a scooter transmission and it looks very similar to that Honda mower setup. There is also a detailed explanation of how it works.
http://www.scooterunderground.ca/knowledge/faq/CVTScooterTransmission.htm
 

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iused to have this same mower-the pully is supposed to open and close up to change the ratio of the ground speed-just like the lawnboy 5 speed . mine worked great . prob the pully halves are stuck together as she never changed speeds. slick desighn -leave it to the japanese. the plastic gears on the drive wheels are the weak link in this otherwise fine desighn
 

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Yep, looks like the "driven pulley" on the inside of scooter "transmissions" I've worked on. Free it up, I'd toss in a new belt, and it'll probably give you a run around the yard.
 

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Lawn-Boy fan
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Actually, maybe just spraying the pully that has the spring with penetrating oil and tapping it with a hammer will free it up enough to get it working again. Of course, you will get oil on the belt, so either take it off, or wipe it down with brake cleaner or something afterwards.
 

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Years back, when I was an employee of the rental business I subsequently bought (and sold), we were a Honda mower dealer. They were very easy to sell, but the speed differences in the drive system were almost negligible. One customer really complained about it, and Honda didn't want to know him, which was typical at the time. AFA I'm concerned, the mower's only redeeming quality was the engine and the BBC, the rest of it was nothing to write home about. Honda also used to run a tremendous paperwork mill, they probably had their own forest to supply the paper. You got the equivalent of the new health care bill about every two months. One day we got the letter that we were no longer a dealer and that was the end of that.
 

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Discussion Starter · #9 ·
Thanks guys. That helped me over the hump and explains the spring on the top of the pulley. Almost surely right that the action on the driven pulley is stuck. The bearing on the idler pulley was stuck solid too, but that was a lot more obvious on my first pass. Armed and dangerous now for the next pass.
 
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