hay as a high school project in my mechanics calss whe have to disasemble car engines and stuff but i wanted to do something kinda cool but i wanted something smaller so it would be cheaper so............................................i had a 4 hp brigs from a rotetiler i fixed up in junior high. anyways i did a port and polish on it this weekend,welded up a strait pipe,polished the head. kinda cool i have pics up in about a day. the port and polish turned out pretty dam good.

 

try to focus on English class now...but sounds cool cant wait to see the pics

 

LOL Mn.[img]i/expressions/face-icon-small-happy.gif[/img] I was thinking the same thing.[img]i/expressions/face-icon-small-wink.gif[/img]

 

cant figure out how to add pics so check out my profile.

 

uhhh... call me crazy, but don't you want the exhaust only to be polished? I mean, on a carb engine, you need some intake turbulence for better fuel/air mixing, right? Exhaust polish, now that's the tickey. High flow=higher power. I'd think you could get almost 8 hp out of a little briggs 5 horse with decent exhaust and a better carb. Wonder what kind of throttle response, though? They have pretty heavy magnetos.

 

i read on the net and i thought that you do both. your suposed to take all of the rough cast out and polish. because the aluminum is cast in sand it leaves it rough. and you take sharp corners off and unnescesary curves exept those that induce swirl. i just didnt do the exhuast yet. didnt have time. more air more fuel lest restrictive breathing= more power right. i cound have got it wrong but anyways who cares its my fool around engine anyways.i also ported out the carb boot that connects to the block. it was smaller than the opening on the block and the carb opening. some people were doing it on their lt250rs i heard. i have a pipe for it to.

 

You can also put a degree key in and change your ignition timing, you can get an adapter and run 3hp flywheel. Aluminum(?) flywheel is lighter and 3hp is smaller. Increases throttle reponse a bunch, less to get moving. Take govenor out and plug hole if you have not already. We used to race go-karts and would jet for race fuel, run 4 degree key(amounts to a partly sheared key), Take starter off of blower housing so you can remove it after starting. Will kick like a mule if you aren't ready for it. I used to mix 3quarts of 20w50 oil with 1 quart of STP for oil and only use 12 oz instead of 16 or 20. My engine set up like above except I had the cast 5hp flywheel would rap out at about 6700 RPM.

 

Back in the day when i was young me and my friends would get riding lawn mowers gear them up(top speed 10-25mph)lol and try all kinds of wacky ideas, porting,ram air etc...

its a great way to learn...

nice photos

TrailRider

 

i did the exhaust port today and will have pics up soon

 

Allright if you want to talk lawnmowers look in my pictures . . A friend of mine in Boise has a Jr Dragster built for his daughter with a 5 Hp base Briggs it pumps out 52HP . No take into account there is nothing on it thats briggs .She went to the Nationals and there was well over 5000 in that engine alone .
And it sounds sweeeeeeeeeeet .
If you ever heard of the Neiborhood knock out thats the car