yamaha or tohatsu?

[Neil_M50D2]

alrighth eres another question, I need an explination of ports and porting, for example on a square port motor, do ya make prts higher or wider to get different types of power out of them, that kinda stuff neone here go any basic explinations of that kinda stuff?

A couple of rules of thumb. Make small changes as you can quickly ruin a block. Find a book on the subject (Two-Stroke TUNER’S HANDBOOK By Gordon Jennings). Talk to someone who has modified the same engine you are working on so you can get the benefit of their mistakes (Fast Fred). Never make a port width more than 65% of the bore. HP is gained by making improvements throughout the engine. All engines have week links, and there is always room for improvement. Probably more and some hilarious stories.

Usually, increasing the port width usually increases torque. Increasing the port height usually increases max RPM. More RPM is usually more HP. Engines have RPM limitations based on rod to stroke length, piston ring type, material strengths and weight of moving parts. The piston’s mean speed should never exceed 3500 ft/min. At high RPM the is a very rapid de-acceleration as the piston stops at the top and comes back down. Depending on the ring type and thickness, at some RPM the ring will lift off their seat and will flutter. This usually breaks a cast iron ring into pieces about 1/16-inches long, just before the engine explodes into pieces. Ductile iron rings do not break, but the lube is blown past the cylinder walls and the engine sticks. There are equations of motion for these subjects that you can get from the named book, or other resources.

This is just the beginning, break a few engines, I did.
Neil Bass

[iwanajohnson]

hah I like tie title on that one, I don't wanna know how to break one I need to know how to keep it togeather, just playin, thanks for the info. where would I be able to find one of those books is it old or would it still be somewhere on the net. thanks

[iwanajohnson]

does that book have some good info in it, it better for as expensive as it is.

[Neil_M50D2]

does that book have some good info in it, it better for as expensive as it is.

If you are worried about the cost of a book, you cannot afford to start modifying an engine.

[iwanajohnson]

If you are worried about the cost of a book, you cannot afford to start modifying an engine.

Yea, good point there, I'm gonna get it I was just kinda shocked, that's as much as my college text books, it's one I acually want though.

[iwanajohnson]

You may be right on that, but iwannachamp just sounds like rockn´roll and then U need,
...well have a look at the small pic below after switching the brand you could then be iamchamp, if you do not switch then you are iamchimp, simple.

Happy tuning

chimp huh, if I switched to a motor that small it'd be slow enough I could have a chimp drive it hehe!!!!

[tthibodaux]

chimp huh, if I switched to a motor that small it'd be slow enough I could have a chimp drive it hehe!!!!

IWANA YAMAHOTSUOMC.. You like that Andrew?

[iwanajohnson]

IWANA YAMAHOTSUOMC.. You like that Andrew?

I like my name, it don't need to be changed, lol, I need to figure out this performance tuning so I can be out threre runnin with yall, how do you pronounce that anyways, it's creative.

[Fast Fred]

Super, Super with carbs, = 46-47+hp per hole with carbs, seems them numbers are not easy to throughdown, no matter how big or how many cyl's it's got. no spray, all Moda, outboard moda on gas

[tthibodaux]

BRF has a rule about not postin pictures of yourself.