Thursday, June 17, 2010

Honda hobbit variator 'notching'

I started making hobbit weights a few years ago for friends and such, because there is really nothing on the aftermarket, and the stock weights are hard steel, which is tough to modify, and the chincy little plastic nubs on them fall off. I started with a few different metals and ended up using a very hard acetal polymer.

I have since learned other moped wizard guru types have been doing this much longer than i have, and came to the same conclusions. I've sold a few through Treatland now, of my best design and manufacturing methods, and there have been some complaints. One of the first test sets i made, had the same problem. The weight pushes out too far and gets pinched, with the sharp steel outer plate digging into the plastic and jamming it in fully variated position. Some R&D confirmed this was due to people improperly 'notching' their variators, so I made a note to doccument it the next time i did it. Peter's Blog has a ton of great info on hopping up Hobbits, including info on variator notching. You should read all of that first, but in how it directly relates to 'Moped Factory' Slick Rick Rollers, I would like to add a bit of detail.

The very important first step in the process is carefully measuring a line around the variator 10 mm from the outside edge. I've done this with a caliper, but if you dont have one a wrench might work well. the exact number isn't super precise (+/- .2 maybe) but making sure its even will keep things balanced and make sure it variates precisely.
From Hobbit Vario Notch


Tape off the line so you can see it and make sure its dead-on. Then get your dremel cut-off wheel out and start cutting just above the taped edge, along where the roller 'track' goes through.
From Hobbit Vario Notch


Next, cut the rest of the window out, along the edges of the roller 'track'. I use the hacksaw because its way faster than the stupid dremel wheels, but maybe you're turbo lazy or something. Either way, cut that out of there.
From Hobbit Vario Notch


You will probably be left with a little material in the corners holding it in, a quick tap tap taparooo with the hammer will bust those chunks out.
Before:
From Hobbit Vario Notch


After:
From Hobbit Vario Notch


This is what it should look like from the inside. Note the fact that the cut edge sticks above the top of the roller track by about 3 mm. This is about the thickness of the cut area... coincidence? i think not!
From Hobbit Vario Notch


Now you just take your grinding bit and extend the ramp through the wall of the variator.
From Hobbit Vario Notch
The key is that you aren't grinding down the original ramp at all, just extending it. What you dont want to do is cut off flush with the top edge of the ramp, and then grind it down, you are changing the clearance between the two ramp surfaces, and now the rollers dont fit. Maybe i'll do a diagram of this later.

When you're finished it should look like this: (or maybe even prettier, if you want to go nuts with fine bits... not that important)
From Hobbit Vario Notch


The key is first and foremost making sure everything is exactly symmetrical with respect to the 3 roller tracks.

For those of you who already screwed up your variators, i'll be shipping out some 'oversized' rollers as soon as i can test them. Hopefully we can save the variators.

14 comments:

  1. Nice work on this, but Stop notching the hobbit variators, WINDOWS is where its at!!!!!

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  2. Yeah, its everyone else fault your product doesn't work right!

    Wow.

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  3. ^^yea, it's your fault for putting it in a poorly notched variator. these are made for a stock variator. not a modified stock variator. graham had to do this whole tutorial for you idiots because you were crying that your weights were getting wrecked, but it was your own fault.

    notch it this way, and theres no problems. if you already notched it the wrong way, theres oversize weights available now.

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  4. i hadn't heard this windows business. put up a post and i'll make this one into one giant link to your blog.

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  5. its the same as notching....but you just leave the whole outer edge intact, so it doesnt slice your leg up if you fall on it while its turning.

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  6. I've made several like this, but instead of just having it open like that we bolted little strips of stainless steel outside the notches. you could just bolt a ring around the whole thing even, just made a nice way to make sure the weights stay in place

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  7. Could I have a somewhat closer-up view of the ramps and a notch in the final product? I'm working on mine now and am still not 100% in what my final product should look like. (If I understand correctly, the final notch bottom should be even with the nearest points on the ramps, but not scarfed in?)

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  8. what are you talking about ? scarfed in ? go back to your MA thread. I explained it there, and gave you the pretty pictures you asked for. http://www.mopedarmy.com/forums/read.php?7,3029446,page=2

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  9. First thank you to share your experience in this tutorial :)

    While you grind the extention of the ramp, is it very important to respect th 10mm dimension of the window or you can grind a little bit more to get a smoother ramp angle ???

    Vince

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  10. Can someone make a blog on installing and tuning honda performance vari like this one http://www.1977mopeds.com/derbi-variant-honda-hobbit-tjt-race-variator.html

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  11. I have a 1979 Honda Camino PA50 Dx (same as the Hobbit) fully restored by me and mostly my father. And I have a problem with worn variable weights not allowing top speed etc. Of course I have seen no after market pieces. My father has connections and will/may be able to get the end plastic nubs/end caps (now worn and cracked) replaced with copper or brass, using a lave at his work. Will this work as the softer metal ends are a lot less likely to crack or wear (itself or the the roller assembly) ? I am weary of cutting the roller assembly wall. Any feedback would be helpful.
    Thank you.

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    Replies
    1. https://www.treatland.tv/

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  12. Pa50ii stock kit with a hobbit black pipe. Topping out at 37-40mph but lost all low end because of pipe. Any quick mods I can do to increase acceleration? Timing change? Or do I just port it hopefully increase power in general?

    ReplyDelete