Modifying The Staton Gearbox For 5:1 Gear Reduction

Discussion in 'Rack Mounted Engines' started by 5-7HEAVEN, Nov 16, 2008.

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  1. 5-7HEAVEN

    5-7HEAVEN Guest

    The Staton gearbox has three gearshafts inside. The first connects to the engine's clutchdrum. That shaft's gear meshes with a 5:1 intermediate shaft which then meshes with the output shaft for an 18.75:1 gear reduction.

    There is only one output shaft on the older-style gearbox, either on the inside or outside of the box. Then the updated gearboxes evolved with output shafts on the left side, right side, both sides AND where the 5:1 intermediate shaft locates.

    Instead of buying a newer gearbox with the 5:1 output shaft, it would seem to be a simple matter to bore a 5/8" hole thru the gearbox left-sidecover. Then you just buy Staton's 5:1 intermediate shaft with 3/4" output shaft for the sprocket.

    For that matter, you could bore the opposite side cover at the main output shaft, buy Staton's later-model output shafts and convert from one-side output to dual sprockets. Orrr, converting the outside drive gearbox to inside drive. You could also bore four holes in the left-side cover to remove the engine's mounting bolts. If you own an older-model Staton gearbox, you KNOW what a PITA it is to remove the engine.

    In other words, upgrading and retrofitting to Staton's newer output shafts and options.

    I had mulled over buying another gearbox with inside drive, especially while dreaming about a NuVinci conversion. This option is WAYYY cheaper than a new box, as the Staton's output shafts are only $29.95. His gearboxes sell for $240-$290.

    On paper, it seems do-able. I want to tap off my Staton gearbox for 5:1 gear reduction to run my 100-watt miniature alternator. The dynamo puts out its power at 1,000rpm, so I need to gear it down from my engine's 8,000 rpm spins.

    So the BIGGG question is.....has anyone modified their Staton gearbox for 5:1 gear reduction?:scooter:
    Last edited by a moderator: Nov 16, 2008

  2. kerf

    kerf Guest

    I've been pondering doing the same thing for an inside drive. Hole needs to be a few thousandths over 5/8 could use the bearing with a bushing to drill pilot.
  3. 5-7HEAVEN

    5-7HEAVEN Guest

    kerf, I'd send it to the machine shop if someone's done it before.

    I'll ask Dave Staton. He'll void my lifetime warranty, but heck it'll cost me $100+ in shipping to him anyway.

    I can swap parts and repair his gearbox. :hammer:

    There's really not much in there.
  4. loquin

    loquin Active Member

    Could you buy a new gearbox cover, as well as the gear with the output shaft? Probably cheaper than sending the old cover to the machine shop...
  5. 5-7HEAVEN

    5-7HEAVEN Guest

    I could ask Dave Staton, but I have a hunch it might be expensive. You can buy all the gears and clutchdrum in the gearbox for $106, which leaves $183 for both covers.

    And his shipping absolutely KILLS me.
    Last edited by a moderator: Nov 19, 2008
  6. Happy Valley

    Happy Valley Active Member

    Oh well 5-7, there's a price for living in paradise.

    It was 14 degrees here last night which is killing me.:elf:
  7. 5-7HEAVEN

    5-7HEAVEN Guest

    Happy, it's 69 degrees now at 4:55am, with todays high and low temps at 79-63 degrees, respectively. Weather is clear and 56% humidity. It rained quite a bit these past few days, but we needed it.

    Many 2-wheel riders here dress in t-shirt, shorts and sandals, no helmet. Crazy fools. I always ride with 3/4 helmet, fluorescent vest, full leather gloves, shin pads and steel-toe boots...and the t-shirt and shorts.:scooter:
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    This 5:1 output shaft is to spin a 100-watt mini-alternator and power my 55-watt headlight, tail and brake light.

    My alternators arrived, and with the proper pulley I should be able to gear it down to 8:1 reduction.

    First I need to find pulleys and a belt to apply what seems to be correct on paper.
  9. 5-7HEAVEN

    5-7HEAVEN Guest

    Staton Said It Could Be Done!

    Well , today I asked the man himself, David Staton, if it was possible to retrofit his 5:1 output shaft onto one of his older model gearbox...

    He said YES!!

    As suspected, ya just have to drill thru the left-side cover and swap in his 16-tooth gearbox cog with extended shaft. No other parts needed except his $26.95 output shaft, and using the existing bearing.

    Dave said it was a simple procedure, and he was not interested in selling his side covers.

    I'm so happy.
  10. kerf

    kerf Guest

    Glad it all worked out. Don't worry, be happy.
  11. 5-7HEAVEN

    5-7HEAVEN Guest

    Hats off to you, kerf. Staton advised me to drill the hole exactly as you mentioned with your good idea.:clap:
  12. kerf

    kerf Guest

    Please let me know how it turns out, it sounds like an option that would be useful.
  13. 5-7HEAVEN

    5-7HEAVEN Guest

    kerf, I actually thought of buying an inside-drive gearbox, so this is a MUCH cheaper alternative. Ya can't go wrong with the cost of Staton's gearbox cogs.
  14. mlcorson

    mlcorson Member

    A technical question: How would you (exactly) match the hole you'd have to drill in the case with the gear shaft? Does the shaft need a bearing in the case?
    Last edited: Nov 22, 2008
  15. 5-7HEAVEN

    5-7HEAVEN Guest

    Kerf had a suggestion on the first page, which was exactly what Staton suggested. I was thinking about having a competent machinist drill the hole.

    Then you replace the existing intermediate shaft with the $29.95 Staton extended shaft and re-use the same bearing.

    This saves you $260 plus shipping, the cost of a newer Staton gearbox model.:clap:
  16. loquin

    loquin Active Member

    Is there a seal around the 'new' shaft?
  17. 5-7HEAVEN

    5-7HEAVEN Guest

    Well, I haven't pulled the gears out, but I can't see any seal from the outside. Dave Staton did not mention any, and I haven't seen any on his website.

    FWIW, there's grease in the Staton gearbox and I haven't seen any leak out.
  18. kerf

    kerf Guest

    Ah yes, a seal, answer is no. The bearing is sealed and and has an interference fit to the housing but not the shaft. If oil lubed, oil will leak between the shaft and inner bearing race, the reason Staton uses grease. I've mixed the Staton grease with a couple of ounces of 90w gear oil to thin it out a little. Seems to help keeping lube on the small cogs and I've seen no ill effects from lube in my clutch. DetonatorTuning wet lubed his box and I think it worked ok.