I have a 13 hp Honda engine. I want to get the most out of it. What is the most cost affective way of supping up a engine like that. My budget is $500.
If it is a combination of things please list.



Thanks

 

is it on a riding mower? whats it gonna be used for?

 

Have it rebuilt and bored out, depending on the engine, kohler, tecumsah, b/s,...

 

Its for a go-kart. What does bored out meen?

 

Have the cylinder made bigger, which then means you have to get a bigger piston, crankshaft, and possibly a new cylinder head. For my kohler engine it cost $400 to have all that done.

 

why would you have to get a bigger crankshaft? Boring and engine doesnt affect the stroke. Also, there arnt exactly a wide range of performance parts for hondas, let along 13hp hondas... 5hp briggs are really the only engines you can rebuild fully with race components, because of the demand from circle track kart racers.

sell the honda engine, and get a blueprinted B/S 5hp... running on methanol they can make something like 16 hp and its a much smaller package.

Jim

 

What does blue printed mean and how do u get it to run on methanol? So if I run it on methanual on a 5hp briggs it should give me 16hp?

 

blueprinting, is measuring, and making sure everything is in spec. to run on methanol, just run it on it, but no it alone won't give you 16hp, your going to have to get a racing carb, racing head, billit connecting rod, racing valves and valve springs, etc. may find something to piece together one on ebay..... though if you go with a 5hp briggs, they sell a nice raptor block http://www.briggsracing.com/display/...p?Docid=101376
or one already to go.......
http://www.briggsracing.com/display/...p?Docid=101375
though it sounds like you don't know much, i would just get a regular 5hp briggs engine. more then powerful enough to do the job

 

I meant, that if you also shave the head, you get the full potential of the engine by using a new crankshaft.

 

You mean by using the same crankshaft?

If you shave the head your reducing the combustion chamber volume, increasing compression ratio. Its like running a stroker crank... a longer connecting rod is only usefull if you have a crank with more offset.

 

On top of what V8 said,

Blue printing is technically bringing the engine back to manufacturing specs using closer tolerances than the factory, making more power. Aka bringing it back into the specs + tolerance specified in the engines "blue prints"

Whether its karting or drag racing, when we say blue print we mean not only bringing it back into spec, but also balancing the crank/rotating assembly, usually new main bearings, alot of times, depending on the level of work being done, new forged rods/wrist pins and pistons. Also, Block is usually decked a few thousandths and the head is shaved an additional few thousandths. Heads are usually ported/polished, cylinders bored... a whole realm of things Many times a new cam(s) and valve train is installed.

Basically, speed=money... the more you spend on the motor work the more power your going to make, however running methanol and making more power reduces the life of the engine, so it will need to be inspectedand "freshened up" more often

Jim

 

Well my uncle knows a lot about engines he used to be the manager for mechanics at Chevrolet. I was just wonderin whats the best engine I could get for under $700. It doesnt have to be just a stock engine. If it is a like say a raptor but like supped up I want to know whats the best way of supping up the engine. EX: Could I have a wesbsite that gives me all of performance parts for briggs?

 

Knowing about engines and building high performance are two different things.

www.tsracing.com has briggs raptor3's on sale for af ew hundred, dont remember the exact price but its a good one. Also, Briggs World Formula(If you can find one used) or Animal engines are all great. Raptor3 is a flathead/lhead, the others are OHV motors

Jim

 

you can try searching google, for 5hp briggs racing parts, raptor engines, etc. though its gonna be pricey, ebay has a few racing parts. mind you, it is different, may be a small engine, but its a high performance engine, its built to race, and withstand alot more rpms.

 

Why would you go from a 13hp Honda to a 5hp Briggs just to supe up the Briggs? You'd be working backwards. Even though there aren't many parts for the Honda, there are things you can do that don't need parts, and other parts can be adapted or made. Here's what you can do-you'll need a good engine performance guy to help you, but you'll save money on buying things you don't need and keep from screwing it up.
-mill the head for higher compression
-polish the ports and maybe reshape them for better flow
-try to find a bigger and better carb(might even see if a briggs will swap)
-free flow exaust
-high flow air filter and airbox

All that stuff can be done cheap. You might even try running methanol, but you'll have to rejet the carb.

 

Yea he has a point. I am not building a racing go kart i am building an offroad one with high performance. I need the higher torque. And more hosepower to make it faster.

 

You cant just shave the head on an OHV engine... then you need to either get different ratio rocker arms or shorter pushrods. It will cost alot of money, especially because its a honda engine. Your not goign to be able to get a better carb really, carbs are usually smoothed out to begin with, and you probably wont be able to get any after market performance parts for a honda.

You can buy a racing briggs motor meant to run on alky from ebay for less than what you could sell that honda for.

Jim

 

I was just offering up some possible suggestions to increase power. I could make them work, but it would require a little machining and ingenuity to locate and adapt parts. Even if you can't tweak a little more power out of your Honda, I think you're better off sticking with it than buying a 5hp B&S and modifying the hell out of it. Right now you have a mildly tuned motor that was built for delivering good useable power, being reliable, and lasting a long time. It has useable torque right off idle and delivers smooth power through the mid range all the way up to its 13hp peak, with 13hp being nothing to laugh at. Now if you were to take a smaller 5hp motor and try to get the same hp or more, you'd have to modify the engine to the very limits of it's design, making it a highly tuned motor. This will rapidly increase engine wear, decrease reliability, and greatly affect the power delivery curve. To get 13hp out of the smaller briggs, you will lose low and mid-range power and torque in exchange for high RPM horsepower, which is good for racing on pavement but not very useful for dirt riding.
13hp really isn't bad. I'd stick with the Honda for the time being until I could find maybe a used 20 or 30 hp 250cc dirt bike motor that could be modified to swap. Try for some real horsepower instead of piddling around with lawnmower engines. I ride a 2001 Honda CR500 with 64 horsepower.

 

since it's for off road, keep the honda, lots of low end, go with a larger 'driven' sprocket or a smaller 'drive' sprocket. if you're gonna modify a 5hp b&s you will lose reliability and driveability. i do kinda like the motorcycle engine idea. 5 speed, clutch, electric start. should be able to pick one up at a decent price.

 

Take your $500 and buy a motorcycle engine like a 250 or 500. More than twice the power of your 13hp honda and made to do what you are asking of it all day long.

 

Yea thats a good idea but do u need to modifie it to be able to run it on a go kart?

 

1. engine mounts, not to tough
2. throttle, easy
3. clutch, easy
4. shifter, solid linkage, a little tougher
5. fuel supply, ? has to be gravity fed
6. electronics, depends on the engine
7. big concern, air flow
8 through 76 the unknown that always pops up when doing something like this,
if it was easy, it wouldn't be fun and everyone else would have one.

 

There would be little, if any, modification to the motor itself. Flopshot summed up all the basic needs. You'll have to set the motor up so cables and levers can be run up front to set up your controls. You'll have to decide how you are going to shift. A ratchet type hand shift with foot clutch, or a motorcycle style foot shift with a hand clutch. I guess you could try to come up with an auto setup like one of the higher power torque converter kits for karts, but you're talking extra money there. A gravity feed fuel tank and a "pod" type air filter on the carb.

 

Thanks! Alot!

 

You can also try an old snowmobile engine. Lots of HP there and you can whole, although old, ones for cheap and use the tans too.

 

Hi, Save your time and money on engine mods and try changing gears {sprocket} in drive line to increase speed.
Best regards, Jeff