The rod doesn't really make it any faster or more powerful, just a hell of a lot harder to blow up.. A big cam and carb and exhaust are probably the easiest way to make it a lot more powerful and give it more top end like an actual racing engine.. Theres a lot of dumb little stuff you can do to them with a file or two and make em run a lot harder just out of the box though..
A good head that's been milled and fire slotted, on Evilbay used parts for 15 bucks to the door, might not be a bad investment either.. lol... Yeah, and the right valves and lifters to match the cam and probably a rod if you're going with a bigger cam.... A stock motor holds together pretty well but ya go throwing a 6,000 rpm cam in a 1/2 worn stock rod motor she might come apart on ya :stuart: I would say look around for an entire kit that has everything you need.. :shifty:
I have a briggs 5 horse and I want this cam in it...... wheres the one with lifters and valves, springs, keepers, that all match itself ??? If you are changing the cam and rod ya might as well hone the cylinder and throw some new rings in it... Port polish at least the intake side if you're trying to go pretty fast.... :doah: Now it's getting complicated huh? :lol:
I have a briggs 5 horse and I want this cam in it...... wheres the one with lifters and valves, springs, keepers, that all match itself ??? If you are changing the cam and rod ya might as well hone the cylinder and throw some new rings in it... Port polish at least the intake side if you're trying to go pretty fast.... :doah: Now it's getting complicated huh? :lol:
lol, I give them port polish jobs with heavy springs and GOOD carburetors and all kinds of tricks on old junkyard rototiller engines with hundreds of hours on them and burn them wide open down the open road for as long as it takes to get where I am going, or wide open in the yard shooting huge rooster tails... and I've never broke one... :shrug: Several several engines... Some with 1/8 inch of up and down play in the crank shaft.. 3 horse turning 4,500 and never broke one. :shrug: They are tough, original cam and some oil in the lower end = you are fine.. :thumbsup:
like i told you once before check your valve clearances and shave your eyebrows its free and easy. every briggs i ever had was way out of spec on the clearances and that affects compression and power alot! Carb and pipe. You dont need a rod if you keep the revs under control. If you keep the stock springs itll keep you from blowing it up too. cams are cheap so you might as well but then you probrobly need springs and a rod
Cheap, and not a lot of labor....air filter and adapter, header, re-jet, lap valves, set valve clearance, de-carbon, get a new exhaust spring, and use your old one on the intake. Since you're installing a billet rod, make sure that the bore is in good shape. If it is, either throw it back together, or ball hone it and replace the rings. If it has points, you can probably pick up a used electronic coil for next to nothing. You should have a peppy little bass then. Maybe someone else will chime in with some more freebie mods. Good luck with it. Scott.
2-3.5 horse power flywheel WILL help your engine build RPMS faster AND get higher TOP END RPMS... BUT TWO things to keep in mind... #1 IF you ad a 3 horse flywheel to a 5 horse engine.. Your coil WILL NOT work... YOU WILL NEED a 3 horse Coil as well to match the radius of the flywheel..(I'd buy a EIC) THEN you have to mount it some how... I just re-drill NEW holes and call it great... you can ALSO drill the NEW holes to the right just slightly and advance you timing all in one shot.. :thumbsup:
.. #2 thing to keep in mind... I saw ONE guy was trying to sell a 3 horse LAWN MOWER ENGINE ALUMINUM flywheel for briggs 5 horse engines. :thumbdown: 20 dollars will buy 7 of those ENTIRE MOTORS from the junkyard.. BUT the worst thing about that is they are WAY TOO lightweight and if your engine isn't totally junk.. the flywheel will not be heavy enough to roll the engine to compression unless it idles at 10,000 rpms.... and IF you DID manage to GET the thing to run... You run the risk of exploding that super thin chinsy POS lawnmower flywheel into about 90 pieces...
.. IF you buy a lightweight flywheel, BUY AN IRON flywheel that BELONGS on these horizontal crank motors, AND an EIC coil to match it....
PS.... MORE free mods... Pull your valves out.. Port/Polish at least the intake port. That allows air to be sucked into the motor faster. I do exhaust too because it's easy and although the stock cam will never feel an ehhaust port job, it makes them BARK like a bitch. My motors are stock cam that sounds like an airplane going by. :freakout: That makes a BIG difference for free. It's kind of a trick but it's actually very simple if you have a router bit made for steel that goes in your drill.... You should look for a good (how to) video on youtube I'd say before attempting that. :hammer:
Then when ya put the valves back in, give them the standard lap them and make sure they seat good and set the clearance on them as you are supposed to, BUT you can grind the stem of the intake valve off a few thousandths over and it will drop the valve shut faster and make a HELL of a lot more compression. :thumbs: I never even measure the gap anymore because after doing enough of them you know what it looks like and I just go by feel by positioning the crank and cam shaft.. There is a certain point in the cam where the valve finally SEATS TIGHT and I roll the engine to that point and grind the stem to seat there and it's done. :shrug:
.. But when I am building a Hillbilly Racer I will take the intake valve off a little extra like a couple thousandths (I should actually measure one I guess for reference) But I will seat the valve at the end of the first drop in the lobe. There is a point the valve drops to BUT remains OPEN some as a built in compresion release.... The piston actually makes compression most of it's travel with a VALVE OPEN.. It's just a fraction but it's enough to be a leak. :doah:.... I would jut say for best guess roll the piston in the right direction until your intake valve is closing and the piston is traveling towards top dead in the compression stroke... I would say roll the piston to about 1/4 of the way up the cylinder then LEAVE the motor sitting just like that.... THEN seat your valve to where it is JUST BARELY starting to be closed completely... I mean you want to hit the mark EXACTLY... I will make 9 or 10 trips to the grinder and barely nibble off like 1/5 of the width of a dollar bill, at a time.. Being sure not to OVER do it... :hammer:
Make sure every time you drop your valve in the hole, MAKE SURE to wipe the end of the valve AND the end of the lifter off CLEAN CLEAN with your finger... If ya get a tiny little anything in between them it will TOTALLY throw off your measurement.. :doah: THEN..... when you have your ports done and valves right... Do like ole boy said and get new exhaust spring (or just another from another motor) and use EXHAUST springs on both valves because they are FAR stronger and will keep the valves from floating.. Those changes will allow the engine to breathe much batter make far more compression resulting in a gain in power, not twice the horse power BUT a big difference... It will have more torque, accelerate faster, get higher RPMs.. :freakout: You can also shave off your flywheel key to advance the spark and gain RPM's but that makes them run kinda rough at low speed ESPECIALLY with Hillbilly intake valves.. :shrug: Get everything perfect and HOLY CRAP you won't believe the difference...
Another thing you can do is throw that briggs carb in the garbage or on Evilbay to get money for a GOOD carb of almost ANY other design that is for the correct horse power, AND has TWO fuel mixture screws. I use a LOT of the Tecumseh bowl style ones because a good one runs EXCELLENT... With two fuel screws you can meter the fuel for the entire power band.. Idles perfectly clean and is perfectly responsive then the high speed dialed in for the perfect amount of extra when you DUMP the air to it... A good one of these backyard racers will low idle as as hell for 11 hours on your go kart... walk up to it, sit down mash the gas and instantly start shooting a loud as hell 42 4,400 rpm rooster tail to hell wouldn't have it...
.. ANOTHER trick for more snap and power is a good head. I use the old 4 horse heads because it's factory old school briggs racer parts.... But you can get used take off parts, aftermarket shaved down fire slotted racing heads for pretty cheap too.. Huge exhaust huge carb mega compression and turned wiiiiiiide open makes them go pretty good. :thumbsup:
.. #2 thing to keep in mind... I saw ONE guy was trying to sell a 3 horse LAWN MOWER ENGINE ALUMINUM flywheel for briggs 5 horse engines. :thumbdown: 20 dollars will buy 7 of those ENTIRE MOTORS from the junkyard.. BUT the worst thing about that is they are WAY TOO lightweight and if your engine isn't totally junk.. the flywheel will not be heavy enough to roll the engine to compression unless it idles at 10,000 rpms.... and IF you DID manage to GET the thing to run... You run the risk of exploding that super thin chinsy POS lawnmower flywheel into about 90 pieces...
.. IF you buy a lightweight flywheel, BUY AN IRON flywheel that BELONGS on these horizontal crank motors, AND an EIC coil to match it....
PS.... MORE free mods... Pull your valves out.. Port/Polish at least the intake port. That allows air to be sucked into the motor faster. I do exhaust too because it's easy and although the stock cam will never feel an ehhaust port job, it makes them BARK like a bitch. My motors are stock cam that sounds like an airplane going by. :freakout: That makes a BIG difference for free. It's kind of a trick but it's actually very simple if you have a router bit made for steel that goes in your drill.... You should look for a good (how to) video on youtube I'd say before attempting that. :hammer:
Then when ya put the valves back in, give them the standard lap them and make sure they seat good and set the clearance on them as you are supposed to, BUT you can grind the stem of the intake valve off a few thousandths over and it will drop the valve shut faster and make a HELL of a lot more compression. :thumbs: I never even measure the gap anymore because after doing enough of them you know what it looks like and I just go by feel by positioning the crank and cam shaft.. There is a certain point in the cam where the valve finally SEATS TIGHT and I roll the engine to that point and grind the stem to seat there and it's done. :shrug:
.. But when I am building a Hillbilly Racer I will take the intake valve off a little extra like a couple thousandths (I should actually measure one I guess for reference) But I will seat the valve at the end of the first drop in the lobe. There is a point the valve drops to BUT remains OPEN some as a built in compresion release.... The piston actually makes compression most of it's travel with a VALVE OPEN.. It's just a fraction but it's enough to be a leak. :doah:.... I would jut say for best guess roll the piston in the right direction until your intake valve is closing and the piston is traveling towards top dead in the compression stroke... I would say roll the piston to about 1/4 of the way up the cylinder then LEAVE the motor sitting just like that.... THEN seat your valve to where it is JUST BARELY starting to be closed completely... I mean you want to hit the mark EXACTLY... I will make 9 or 10 trips to the grinder and barely nibble off like 1/5 of the width of a dollar bill, at a time.. Being sure not to OVER do it... :hammer:
Make sure every time you drop your valve in the hole, MAKE SURE to wipe the end of the valve AND the end of the lifter off CLEAN CLEAN with your finger... If ya get a tiny little anything in between them it will TOTALLY throw off your measurement.. :doah: THEN..... when you have your ports done and valves right... Do like ole boy said and get new exhaust spring (or just another from another motor) and use EXHAUST springs on both valves because they are FAR stronger and will keep the valves from floating.. Those changes will allow the engine to breathe much batter make far more compression resulting in a gain in power, not twice the horse power BUT a big difference... It will have more torque, accelerate faster, get higher RPMs.. :freakout: You can also shave off your flywheel key to advance the spark and gain RPM's but that makes them run kinda rough at low speed ESPECIALLY with Hillbilly intake valves.. :shrug: Get everything perfect and HOLY CRAP you won't believe the difference...
Another thing you can do is throw that briggs carb in the garbage or on Evilbay to get money for a GOOD carb of almost ANY other design that is for the correct horse power, AND has TWO fuel mixture screws. I use a LOT of the Tecumseh bowl style ones because a good one runs EXCELLENT... With two fuel screws you can meter the fuel for the entire power band.. Idles perfectly clean and is perfectly responsive then the high speed dialed in for the perfect amount of extra when you DUMP the air to it... A good one of these backyard racers will low idle as as hell for 11 hours on your go kart... walk up to it, sit down mash the gas and instantly start shooting a loud as hell 42 4,400 rpm rooster tail to hell wouldn't have it...
.. ANOTHER trick for more snap and power is a good head. I use the old 4 horse heads because it's factory old school briggs racer parts.... But you can get used take off parts, aftermarket shaved down fire slotted racing heads for pretty cheap too.. Huge exhaust huge carb mega compression and turned wiiiiiiide open makes them go pretty good. :thumbsup:
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