From: couyant@convex.com (George Couyant)
Subject: Submarines
Organization: CONVEX Computer Corporation, Richardson, Tx., USA
Date: Tue, 28 Jul 1992 06:09:19 GMT
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.


One fine poster emailed me reminding me that I promised to post instructions 
on making TT's go through anything deeper than ankle depth water.

These instructions may apply to other bikes if they just seem to stall for
no reason when the water gets to about carby height. TT's just happen to
be well known for it..

Firstly, the reason they stall is that the carby and overflow design doesn't
let it meter fuel properly once the overflow/breather tube is blocked or
if there's pressure pushing air back into the float bowl.

You have to modify the overflow so that it lets the float bowl breath _and_ 
so that it can let fuel out if needed.

The parts you need are:

	- few feet of plastic tube or fuel line of the same diameter as the
	  overflow. (typically 1/4")
	- 1/4" T piece
	- 1/4" low pressure one way valve
	- tiny bit of filter foam

What you'll do is route the tube from say, behind the headlight or high on
the frame backbone under the seat, down to the carby overflow outlet. Cut
the tube and insert the T piece as per the diagram below. Plug the one way 
valve in with the flow direction pointing down. ie. so that fuel can flow 
down but nothing gets up. 

Shove a bit of air filter foam into the top of the tube (but not too
tight) so that air can get through. This'll keep dust, stones and small
birds from getting into the tubing.

Use your common sense when routing and positioning the tubing. You want
the top of it as high up as you can go whilst keeping it away from water
and damage.

	     _   <-------  Up as high as you can go.
Bit of ---> | \
filter foam.    \
	          \
		   \
		    |
		    |
	      __    |
             |  |   |
	     |__|   |
Carby --->  |    |--| <---- "T" piece.
            |____|  !
	           |v| <---- One way valve to let fuel flow out, but
                   |_|       not let water up.
		    |
		    |

While I'm at it, a few pointers....

1. If you can't see the bottom, get off and walk the bike across with the
   motor off.

2. When you're walking it, stand downstream of the bike. The water will be
   pushing the bike against you and you can lean into the bike giving you
   good support.

3. Try and stand on the pegs with your weight back when riding through.
   This'll give you a number of advantages, such as being able to see
   better into the water ahead, unweighted front ready for you to gas it
   if you hit a hidden rock and of course, the bike can move around
   beneath you whilst you're still in control.

4. If you do drop it, pick it up straight away and don't try to start it 
   in the water. If it's taken a lung full of water, you'll only damage
   the motor.

5. If it has drowned, you need to check air box and filter, drain the carby 
   float bowl, fuel tank (water's more dense than gas, so it sinks) and pull 
   the plug out and dry it and kick it to get any water out from the 
   cylinder. 

   Cheers and happy submarining!
   George C.

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