350CC Rossi- Gearbox - Gas Tank

[Dave M]

Are the 350 guys using the Yamato Hatchet unit under the Rossi 350CC ? If so, would the horizontal (Straight Cut Gears) gearbox hold up ? Or is the Vertical Split (Spiral cut gears) the choice with Yamato Hatchet units.

Also, what gear ratio is prefered ?

Also, what kind of gas tanks are used ? I have seen everything from a fishing 5 gallon tank to a Dick Ficket tank. What is optimal for size and is anything needed for it ? I see people blowing up the tanks prior to starting the engine.

[diamondprohydro]

Dave,

Some seem to prefer the Yamato foot for a touch more control but both the Konny & Rossi foot works well too. 12:15 is the preferred for a lot of reasons but mostly rpm range. We can talk about what & why the foot fails.

As far as fuel tanks, because the system is pressurized using a check-valve set at 2.5 lbs., you need a good tank that will hold the pressure and hold about 4 gal of fuel for those long heats on either a record course or nationals.

Call me anytime to talk about it.

Bill Diamond (253) 377-6493

[Mike Schmidt]

Yamato Gearcases

You need 12:15 spiral cut gears. The staight cut gears just will not live under a 350. (They won't live under a good 250...) Either case design is O.K. It is all how you shim them. Konny builds a prop shaft for the Yamato unit that is stronger than the stock Yamato one. If you run up high with more than 4 blades, the Yamato unit seems to be more stable than the Konig / Rossi style unit.

The oil tanks are nice, but I like welded aluminum ones that fit the boat. Dick Fickett tought me how to weld many many years ago.

Give Rex Hall a call and ask him about the 350 twin Rossi. If you get one, call me and I will give you a prop # that works very well.

Say Hi to your dad for me.

Michael D-1

[Steve Johnson]

Got tank?

Just so happens I have one for sale; Alum needs cap $ 40.00 9524404744

[Dave M]

Pressurized

Is there a special gadget used to pressurize the tank ? I assum if you have a 4.5 gallon fuel tank (fuel becuse it is not a dam gas burner...hehehe) this will leave enough volumn for pressurizing and a little extra methonal.

Any reccomendations on mixes and oil ?

[diamondprohydro]

You just use a check-valve and crankcase pressure. Get the check-vavle from Rex Hall so it is pre-set. Make sure that if you use a shallow tank, your air comes in on opposite end or not on top of where fuel pick-up is.

[Al Peffley]

Oil Choices and More Fuel Info

Oil -- Some of us use the Redline 2-Cycle Alcohol (alky) Fuel Mix (AFM) like me (comes in 1-gallon jugs), others use pure castor oil (leaves a nasty, sticky residue), or still others use the Blenzoil(sp?) mix oil. Mix one quart of any of these oils to 5 gallons of Methanol fuel for a 20:1 ratio. Some racers are using less than 1 quart per five gallons, so check with your oil manufacturer's technical department (through their Website) and your motor manufacturer rep for mix options. Clean your carb float bowls out with a gasoline/oil fuel mix and fog your engine down with Marvel Mystery Oil (pull the plugs and kill switch - crank the motor over and watch for oil mist coming out of the plug holes and then stop cranking) after every race. Plug up carb throats with caps or good quality towels (that don't shed), cap exhaust pipe tips, and plug all fuel lines to the tank after racing (especially the check valve line, according to Ed Thirlby).

Fuel -- Be sure that the source you buy your methanol fuel from has "fresh" RACING fuel (they need to sell enough fuel to replace an opened supply drum in a reasonable time period -- say 6 months, or less.) Mark your mixed oil and fuel jugs as "Mix" so you don't make the mistake of running straight methanol out of a reserve fuel jug by accident! Methanol draws water from the air every time the container is opened and also from the ground through porous storage containers. I store my fuel in plastic jug containers that are made for racing fuel storage (like the 5-gallon thick plastic ones sold at most motorcycle and kart stores.) I keep a board under my containers (when they are in storage in my garage) between the jug and the cement floor to reduce moisture draw. Some racers have a meter to check the water content in their stored fuel.

I tried a new alky oil mix formula that Redline sent me for the AOF Nationals that really worked well and left much less gray residue in the motor. I hope they replace the existing AFM oil formula with this newer formula. Methanol reacts with aluminum and sometimes leaves a gray residue in the fuel system.

Filters -- Use (1) the in-line, Mercedes plastic fuel filter, OR (2) premium (aluminum canister metal container) kart fuel filter with a replaceable, fine porous ceramic core in your transparent fuel lines made for methanol -- check your local kart racing pro shop for these filters and line material as they also use both of these filter types for the large 125cc pro kart engines.

Check Valve for Yamatos: I use two Ford check valves mounted in series in the tank pressure line (for my full-pressure Yamato 250) in case one valve becomes defective during a race. Stick with the Konig low pressure style if you run a Rossi or a Konig/Konny. TMI???

Al Peffley
15-R/R-25

[iyoder]

I'm from michigan also and have found Ed Thirlby alot of help getting started.

[Dave M]

Thanks All

This is great info I needed.