Tuesday 22 September 2009

I give up.

Damn that Pareto guy and his damned 80-20 rule. You know the one that states that "80 percent of a company's revenue comes from 20 percent of its products" or "80 percent of all speeding violations are committed by 20 percent of the drivers" etc, etc. In my case it's: "80 percent of the build time is taken up by 20 percent of the components". Make that "stupid small stuff that I hadn't expected to be such a hassle".

At the moment it's the speedo issue that's driving me crazy. The speedo drive turns the cable 2,8 revolutions for every revolution of the wheel (I've measured it). When I mention this fact to people who sell speedos, the line goes quiet. Then they start babbling that "Most Harley Davidsons..." or "I know that old Shovels use a 1:1 ratio..." or something else irrelevant (99,999 % of all aftermarket speedos are for Harleys, it appears). And when I add that I now have a 19 inch wheel (rather than the 17 inch wheel of the Ducati 996 that the speedo drive comes from) they tell me – in order to make me go away – that I will never be able to get the correct gearing ratio. And without the correct ratio the speedo won't show the correct speed. And that means I won't be able to get my M.O.T.

"Well, change the speedo drive then", I hear you say. But, alas, I can't. The front spindle is 25 mm and the only speedo drive large enough is the Ducati one I already have. I've thought about some sort of solution where I could machine the spindle down to something like 20 mm (so that I can use some kind of jap speedo drive), but then I need some sort of sleeve to thread over the the end of the spindle, in order for it to fit the forks, and I don't like that thought at all. And besides, I don't want to throw away my exquisitely machined, hollow, stainless spindle.


So. Enough is enough. I've decided to eat my words, and go with an electronic speedo. I've found one from trailtech. It's called Vapor Stealth, it's black and it's OK looking. The superbly helpful technician I spoke with (why are all US help line operators so genuinely helpful and friendly BTW?) informed me that the installation is quite easy and even the RPM tachometer graph works on my Husky (despite the fact that it didn't come with a tach to start with), using a simple lead that wraps around the spark plug lead.
Looking at my front disc I now realise that the good people at Braking had foreseen my failure to sort the mechanical speedo and have machined a little eyelet for the sensor magnet into the disc carrier. Hm...

7 comments:

  1. I've been thinking about getting one of these too, after having some rotten luck with an expensive analog tach/speedo unit made by SPA (~$400USD). Honestly the fault is mine for screwing up the install, but it uses a magnetic pickup much like the trailtechs do. I just prefer a nice round analog readout over LCD.

    Everybody says the Trailtechs work great so you're probably going to be fine. What kind of bracket does the Stealth come with?

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  2. I totally agree. A classic speedo is much nicer. I've ordered mine from the UK distributor, but the black one I wanted doesn't arrive in the UK until next week. The guy I spoke with recomended an angled bracket. I'll see if that works out. Otherwise I'll do one of my own.

    To bad that your expensive speedo didn't work out. What went wrong?

    /D

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  3. My first one got fried because I'm colorblind and crossed the supply/ground. they tried to fix it but couldn't. replacement sent to me in mail was stolen from my doorstep.

    Alack, I'm looking into a nice analog speedo made by VDO as a possibility. cost is a lot less anyway...

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  4. I talked to the VDO distributor in Los Angeles, but you can get them other places (I think summit racing has 'em). Here's the speedo that I like:

    http://www.nhspeedometer.com/vision.htm

    He said that the sender part #340020 here would work with a magnet attached to my wheel:
    http://www.nhspeedometer.com/senders.htm

    I don't know about that sender, it looks pretty clunky 2" long and 3/4" threads. Maybe it's okay because I'll need it to reach inward from where I'd mount it off of the axle bracket on my fork.

    I've priced the guage at places for around $120USD and the sender in the $60 range.

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  5. dUCATI SPEEDO DRIVES COME IN TWO RATIOS , ONE FOR A 60 PROFILE TYRE (748) AND ONE FOR 70 (916) THIS MAY HELP ?
    #59

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  6. Thanks Outtacontrolla, but the problem is that I can't find a speedo that matches the Duc speedo drive. The only ones are those mounted to Ducatis and I don't really like those. And they won't have the right ratios for my 19 inch front wheel anyway...

    /David

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