Mirage Replacement Sprockets have Too Small Holes

Hi.

Both of my Mirages (Outback and Sport) came with drives that I later found out had misdrilled flipper mast set screw holes. After one failed I took the problem to my dealer and Hobie was kind enough to send 4 corrected replacement sprockets (though I had hoped they'd include installation as well).

When I got the replacement sprockets home I found that my existing mast set screws would not thread into any of four new sprockets. Back to the dealer I went, where they made the set screws holes slightly larger. They now accepted the set screws very well, so back home I went to put my drives back together. But now I find that in addition to the set screw holes being too small, SO IS MY FLIPPER MAST HOLES! I'll have to return to the dealer this next week once again to have those reamed as well.

Hobie, what's going on here!

And should I attempt to ream the holes myself?

(Note: The set screw and flipper mast holes were too small in ALL 4 replacement sprockets.)

Thomas

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Absolute kayaking corrupts absolutely.

You want the mast holes as tight as you get get them. Helps prevent wobble that may lossen the set screw.

I'd try a VERY small dap of vasaline around the mast and see if it "screws" in underpressure. Or try very light taps to the end of the mast.

Make sure before doing the above that first you fingernail polish the mast opposite side of the flat grove so you can line up to the set screw

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Hi Thomas,

The set screws aren't too small, but just not pre-threaded. They can be a bear to install without a power driver! The reason for this is that the older screws could get loose and back out. These stay in place much better, once you get them threaded! Be sure to thread them in all the way into the notch.

The new holes are tight, but the masts will fit. This is to insure a snug fit. THEY SHOULD NOT BE REAMED IN ANY WAY! Once the mast starts wobbling, it will eventually wear out the hole.
Here are a few tips that may be helpful:

1. Make sure the hole is clear of plastic shavings

2. Pre-mark the flat spot on your mast with a sharpie so you'll know where it is when the fiat spot is hidden.

3. Use a little soapy water to help the mast slip in (the soap will leach out later).

4. Using padded pliers, twist the mast as you insert it. When you get it in as far as you can, line it up (with the pliers if necessary) using your mark and tap it a few times to seat it.

5. If your screws are loose, now that the dealer "fixed" them, use a drop of Loctite blue to keep them in.

6. When you think the screws are tight, try rotating the mast with pliers. Tighten the screw until the mast no longer rotates, but don't over tighten.

7. If the screw is recessed when finished, you did it right. If it still sticks out, the screw may be hanging up on one of the ledges (if there is an option, I use the single flat spot; if the flat spot is split, I file off the middle ledge, as my screws tend to hang up on it).

With practice, it's easy to know what to look for, but the first time, it can be difficult to get it right! Good luck!

Thanks for the great tips. I'll try the soapy water and also mark the masts. BTW, I mentioned that the dealer widened the set screw holes, but I think technically he just retapped the hole's threads a bit.

Just a heads-up: Before I took the drive apart, I took a sharpy and marked the chain link that went onto the center sprocket tooth for each flipper assembly. THAT was a big help in putting the components back together again.

I should also mention that the newly installed Turbo STs I now have on one of my two drives is really neat. Yes, I peddle harder but I also go faster. In a hard peddle it feels like the flippers are actually lifting my Outback up a tad and that causes the boat to bob a bit in smooth water! When I go back to my standard flippers (on my 2nd drive), it's like they are not even there and it all feels like mush.

Thomas

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Absolute kayaking corrupts absolutely.

Thomas,

I have read a few discussions on the "bobbing" thing and what I heard made a lot of sense from an engineering point of view. The theory I heard was that if you are stroking the full allowable stroke, the last bit of the fins movement is almost verticle which would pull the boat down. The beginning of the next stroke would cause an apposite effect with the fins going down almost vertically at first, pushing the boat upwards for a very brief period.

I have shortened up my stroke a bit, have lost no speed, but have noticeably less of the "bobbing".

Roger

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Roger
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