Timing Questions

I have a Thunder Tiger 46 to convert to C/L.
What venturi insert inside diameter can anyone recommend.
and how many degrees exhaust timing and how many degrees for lift.
I have the same question for a OS LA 46.

Will appreciate any help.
Thanks
BobM

>I have a Thunder Tiger 46
>to convert to C/L.
>What venturi insert inside diameter can
>anyone recommend.
>and how many degrees exhaust timing
>and how many degrees for lift.
>I have the same question for
>a OS LA 46.
>
>Will appreciate any help.
>Thanks
>BobM

The Thunder Tiger uses a "true venturi" where the needle does not restrict the air flow. As such it uses a much smaller venturi than the OS, for instance. On this a .169 or .173 will be good for a start.

On the 46 LA a .282 is a good choice if you are using the OS needle valve assembly. If you go to a Super Tigre, then open it to about .298. This is what I have been supplying for this engine.

Timing is an individual choice, and I will let others comment on this one if they want to. For the LA, I, personally, wouldn't even bother to try to change it. Others may disagree, but this engine is missing the boost port. One thing I have learned in this business, if you have the same type of engine reworked by 5 different people, you will probably have 5 different solutions to the same problem. And a lot will depend on head shape (leave it alone or change it), whether or not you drop the sleeve--and how much, venturi size, fuel recommendations, prop recommendations, etc. It is kind of a complex question.