HCR 2011 creek and river crossing modifications are suggested for a trouble free event ride. Here are some of the previous posts on the subject which may be of assistance.
Given the ride is early April it may be dry however there will still be creek and rivers to cross in the high country.
HCR Course enquiries-Tim Dykes
To prevent a bike from stopping during river corssings, here some info on how to fix that.
When the tubes that go to the bottom of the bike go under water it stops atmospheric pressure from pushing on the fuel in the bowl. There is a lower than atmosphere pressure in the venturi. The fuel moves from the higher pressure in the fuel bowl to the lower pressure area in the venturi. The amount of fuel that moves is controlled by the different jets in the fuel circuits.
I'm fairly sure the most bikes WR's DR's etc run the same carb as the 05-07 Husqvarnas, if so your carby should look more or less like this.
On each side of the carb there are breathers, that way it doesn't matter which side you drop the bike on the excess fuel will overflow from the lower side.
Looking at the pictures below and using my yet to be cleaned from the weekend Husqvarna as the example. The Husky has a T piece on each side of the carby with two hoses coming out of it that both originally went down to the bottom of the bike.
I took the one that was facing up from the T and ran it up and down the main tube like this.
This is where there was five tubes, one radiator overflow, four from the carby, now only three.
HCR Course enquiries WR's
Yamaha WR250 and 450s are exactly the same as what Tim has shown above. Once this mod is done there are no more problems going through deep water, so long as you don't drop the bike!
Older WRs also needed a mod to the crankcase breather that comes out of the top of the cover over the cam shafts. Later models have this breather routed to the air box, so no problem, but earlier models like the 03, 05 and maybe the 05, this breather ran down the front of the engine down into where it could easily be under water. To fix this all you need do is cut the hose up near the top and with a "T" piece add a second bit of hose that then breaths up under the tank or seat - well out of the water. I found that watering sysytem plastic fittings and hose were just the right size.
Dennis Dorman
AMTRA.com.au
