By MaxRules (Brandon_price) on Unrecorded Date: Edit

I have done a lot of mods to my 14hp Briggs. It turned out great but of course I still wanted more. I bought all the stuff needed to put dual exhuasts on it, but later decided it would not be a very good set up to run duals out the back. It would make more power but all that pipe just didn't look good. Today, with a hacksaw and a little elbow grease, I cut the muffler off my Max. I cut it an inch after the flex pipe connects to the muffler. It took me 45 minutes to cut that thing off. After the muffler was off, I put an exhaust tip in its place to make it sound good.
Now for the fun part... start it up and see how it runs. I cranked it up and was suprised on how quiet the idle was. I hit the gas and WOW!!! It rumbled like a 454 with Flowmaster exhaust! It sounded so good I already had a smile on my face before I even rode it!
I dropped it into gear and drove down a woods trail. I expected a slight power increase, but nothing like what I felt when I nailed the throttle. It took off like a rocket with power and accelleration like never before. It buried 4000 RPM like nothing and was climbing fast. Well I could go on and on. It is so fast it gets completely out of hand on woods trails.
The Ultimax
Bored .030"
Planed heads
Ported and polished
32mm Mikuni snowmobile carburetor
No governor
Unmuffled pipe with exhaust tip

MaxRules!

By matt435 on Unrecorded Date: Edit

Brandon, That is what I am talking about!!!!!!
Will you bring it to the Attica ride in a few weeks? My 1968 argo that I put the 18 vangaurd has the muffler to close to the body and it gets hot. I might say the heck with a muffler and take mine off too!!! I will try it this weekend and let you all know. Remember brandon, I have a 18 vangaurd with no gov. from the factory and a old machine with small sprokets. I just might leave you in the dust at attica in the sand dunes. Up for the race? Matt

By Smokey 2 Cycle on Unrecorded Date: Edit

Do you guys running w/o mufflers have any problems with requirements in your states that you have an approved spark arrestor installed? Many states require spark arrestors on outdoor equipment. Just wondering about this.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

State parks and some riding areas might require it. All the areas I ride at, with the exception of Turkey Bay, have no muffler requirements. On my own property it doesn't matter. I was out at 11pm last night running it around, breaking the silence...

MaxRules

By mr. philip osborn on Unrecorded Date: Edit

so brandon, that was you i heard last night, all the way up the ohio valley into so. ont.
well sumptin us old guys learn't in the 70's was less sound equalls more (riding) ground. another thing we learned in the 80's was tuned muffled motors made more power.
"definately" check out supertrapp* for puurrformance silencers.
p.s. sorry to hear about yer hustler!

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Hey Phil, I have my pipe set up so that with a small adapter piece I can put the muffler back on. I can use the muffler and lose my power if I go back to Turkey Bay. But then again, those people don't look at it. My Max is quieter than most of those sport quads, so they would not know it didn't have a muffler.
I completely disagree that a performance muffler would make more power. This would make more power than a stock muffler, and still be quieter. My set up makes more power than a performance pipe, but with more noise. Take a look at some pulling trucks or dragsters... no mufflers on them.

MaxRules

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Matt, I'm game for that one. I really want to see if I can pass that 25hp Max IV. I'm sure I can but with all this racing I'll end up blowing the motor up!
People tell me the Vanguard can handle 6000RPM. I've had mine, before taking off the muffler, to 4800RPM. That thing was rapped out big time.
Only three more weeks!

MaxRules

By Steve J on Unrecorded Date: Edit

Brandon,

Some engines are set up to run with a certain amount of back pressure. The Briggs engines are designed to have some back presure primarily because of the head design. In contrast a dragster or pulling tractor may have domed pistons and larger valves in conjunction with an internal cam shaft. That is why these types of engines make more power unrestricted. Keep in mind the length of the exhaust makes a difference also and the Briggs engines don't have much pipe for restrictions.


Steve

By mr. philip osborn on Unrecorded Date: Edit

brandon,
the idea behind the backpressure & megaphone design of the SuperTrapp* is suppose to scavenge exhaust gas out quicker, thus allowing better cylinder head breathing.
think of blowin out air from your mouth through a straw, then try it with restricting it at the end with your finger. you will have created a small amount of pressure that will release the air faster.
they come in 7/8" inlet and up, in all popular sizes.
an if you take your max2 to a 'rave party, simply remove all the disc's and blast away!

By Attex Bob on Unrecorded Date: Edit

"The Briggs engines are designed to have some back presure primarily because of the head design" Say what??? Since when??? An engine is an air pump, it's that simple. Brandon is dead on, the less restrictions you have the more power you make. Brandon, you can move your torque curve around by lengthing the pipe or by shorting the pipe. As a general rule, the longer the pipe the lower the RPM the torque curve comes in. Brandon, the pipes we run out here on the racing 5HP Briggs have a pipe that is about 12" long.(Thats a guess) Don't get too short with the pipe or you will start to lose low end torque. They run these pipes for the venturi effect that they have, not for backpressure. If you look at some racing Briggs stores they will have some of these pipes. They are really pricey though. I'm not surprised that you picked up a bunch of power. To pick up a bunch more, try an K&N intake filter, you will like it!!!

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

HEY BRANDOM: watch out with this "free flow" exaust system.... you can burn your exaust valve...they can only accept certain amount of heat...."extra" rpm on engine and richer gas mixture produce more heat on combustion chamber but less "heat transfer time" between exaust valve
and his seat......after burned you get low compression on engine or complete exaust valve's head off...(ummh..piston and cylinder head doesn't like that!!)........

By Sidney Webb (Sidneywebb) on Unrecorded Date: Edit

I'm not an expert in these type engines, but I DO know that with very small 2-cycle engines such as used for model airplanes, running methanol, and similar size 4-cycle engines running gasoline, a tuned exhaust system actually forces some of the unburned exhaust back into the cylinder through the exhaust port when the engine "comes on" to the pipe. A standing wave develops in the pipe and unburned fuel is reflected back into the engine to be burned. The power range is therefore very "peaky," only a few hundred rpm wide, but the power gain is on the order of 100% (in that narrow rpm range). I ran RC boats with such tuned pipes back in the 70's. Not very useful if you need a wide range of throttle, but amazing how much difference it makes at top rpm when the engine gets on the pipe. Perhaps that's what the writer was referring to.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Thanks for backing me up Attex Bob. I use an Uni filter right now but have considered getting a K&N. I got a carburetor for my Hustler today and it came with a K&N. I should have it running this weekend.
Isaac I am aware of the valve problems you are talking about. I should be ok since i am using the stock manifold. Damaged valves would result from taking off the manifold completely. Having my pipes way too short might do it also, but like Attex Bob said, my torque would decrease and I don't want that to happen.

MaxRules

By fred sain on Unrecorded Date: Edit

Gentlemen: The small engines that are in the Max and Argo are not set up to run over 4000 RPM,s.
You need to check with the manufactor about the kind of RPM,s you are setting them up for. This could turn into a very short lived power boost, and a very costly one.

By MAXEUROPE on Unrecorded Date: Edit

The Vanguard's are good for 6000rpm when un governed - don't worry!!

By Attex Bob on Unrecorded Date: Edit

Hey Brandon: You sound like the type of person that is handy with a welder and has alot of time on his hands. Try this. Make a pipe about a 1/2" long with a flange that fits the exact I.D. of your Briggs head (port match it). Now weld a washer on the flange next to the head that is 1/4" bigger than the O.D.of the first pipe. Now weld a header pipe to that washer.You should now have a pipe within a pipe with a 1/4" airgap. Get what I'm trying to say? This pipe design is called a anti-reversion pipe or AR pipe for short. With a big overlap cam it will help your power out some, and with a stock cam it will probably do nothing for power; but it will not hurt it. I knew a guy that flat tracked Harleys and it helped his power a bunch. Or you can forget all of this weanee power stuff and buy a nitrous kit. One word of caution: Brandon I think you already know this but I will say it again: Be careful with mixture!!!!!! This is an air cool motor and they don't like getting really hot!!!! With all your exhaust and intake work this thing is going to run lean!!!! I have been following the build-up you have done and I don't want to see you burn this thing down!!!!! If you get these things on the edge they have a tendency too........well.........blow up!!!!!!!!

By Steve J on Unrecorded Date: Edit

Attex Bob,

Sounds you are trying to make a hacked up piece of nothin to me......weld this, cut that, Nitrous, what are you talking about? This is a 6x6 not a drag car. Call Briggs and ask them if they recommend running back pressure on their engines.

Steve

By mr. philip osborn on Unrecorded Date: Edit

attex bob, if you feel that exhaust scavenging and back pressure are nonfunctional in 4 stroke exhaust evacuation, then why are you telling brandon to build a reversion pipe?

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Attex Bob, I'm about done with the mods on this engine. There is really nothing more I can do and still have it reliable.
Steve, I'm sure Briggs would say they must have back pressure and I have to use the stock muffler. Also, the engine can't be run over 3600RPM, you should never put a bigger carb on it, and you certainly shouldn't shave the heads. Keep it stock.

I've put about two hours on my Max since I cut the muffler off. It still runs better than ever. I've got some leaner main jets coming in tomorrow. I've needed them for a long time. Once I get the carb tuned in it should be even better. I might advance the timing if I get board over the four day weekend.

MaxRules

By Attex Bob on Unrecorded Date: Edit

Steve: I'm not trying to build anything. I have a 500cc two stroke that does not need any power improvements. 45 MPH is more than enough for me. Brandon has been improving the power of his max for along time (and doing a good job in IMHO) and I am simply suggesting a simple modification for someone who "knows" how to improve on power. If you call a simple modification that does not hurt reliability any a hack job well.....ha ha ha ha. If you have no intrest or the aptitude for power improvements; so be it. Brandon loves power; and from the previous posts he has written, I'm sure he can handle this modifiction if "he" so chooses. Brandon answered the Briggs question for me. Mr. Osborn: Where did I say that exhaust scavenging does not work on a 4 stroke? Exhaust scavenging is critical on a two stroke; and is wanted on a 4 stroke for optimum performance. Back pressure and exhaust scavenging are two different things entirely. Ex: Back pressure is always bad; exhaust scavenging is always good. Backpressure contaminates the incoming mixture by letting the burned exhaust hang out in the combustion chamber. Scavenging pulls the burned exhaust out of the combustion chamber, letting a new fuel air charge to fill the chamber. Reversion also contaminates the chamber (Hence the mod) but happens very little with a stock camshaft. I hope this cleared things up for you.

By john prince on Unrecorded Date: Edit

Attex Bob or whomever??? I'm running a 16hp B&S in an Argo...didn't know you could get a K&N airfilter? Where did you get it or did you have to cut it to fit? Also, would like to see that engine have a little more pulling power uphill. Any ideas?

By Attex Bob on Unrecorded Date: Edit

John: I know what you mean. I have a Argo 8X8 and it has a Tecumseh 16 HP like yours. I Hunted for a 1/2 hour and found my K&N filter book. They make a ton of different filters. I don't know the dimensions of your Briggs filter. If you can post those I would be glad to match one up for you. About the power thing........Thats a tough nut to crack....If you up your compression then you can't run pump gas. You could change out your muffler......but then things get loud. You could change to a better cam than what the factory makes. But that is difficult and can get expensive. When I rebuilt my engine, I did what Brandon did and blueprinted everything I could. I hate to say this, but if I had to do it over again I would have put a big motorcycle engine in the thing. Fortunately you said " a little" more power and that is what you are going to get. I would 1. Install a K&N filter. 2. Install a good preformance muffler. 3. Make a fresh air ducting (to the Carb.)for your Argo. 4. Run a full sythentic oil. Together, all four are going to to make a fair size preformance increase without hurting the reliability of your engine; in fact it will make it last longer. John; only you can answer the question if this is enought power for your liking. If you are only putting out 16HP to begin with, a 5 horsepower increase is hard to get without getting wild with the modifictions. One word of caution; if you decide to make a fresh air package for your Argo, make sure you make a water drain for the intake. Or if you have a roll bar you can put the airfilter on the bar and ducted it to the engine. Like Hummers do. Good luck with the mods John; I think you will like the results.

By john prince on Unrecorded Date: Edit

Attex Bob. I am going to take this info to my motorcycle mechanic(I don't have great mechanic exp). Meanwhile I'll measure the airfilter size and get back. About the only thing I think difficult would be the fresh air ducting. I am guessing tweeking this 16hp to get closer to 18hp performance would radically change my situation since I am so often in steep terrain.

By Argotony on Unrecorded Date: Edit

Fresh air duct...that sounds like a good idea..thx Bob..


Tony

By john prince on Unrecorded Date: Edit

Attex Bob: my air filter is 7" diameter round, 2.25" deep. Where would you look for after market extractor type muffler system?

By George on Unrecorded Date: Edit

Bob,

I have a chief. There appears to be an air filtration system right behind the carb. It's part of the ATV and is tear shaped. Is this part of the filter system? Does any other filter go over the Carb?


Thanks,
George

By john prince on Unrecorded Date: Edit

Attex Bob...ordered K&N filter(special order...but priced right)...still wondering where to look for aftermarket extraction type muffler(small scale ofcourse). If all this works, probably happy with Van 2...if not I'm looking for the next up model with bigger engine. Hard to beat cchorsepower. A bigfoot with a Kawasaki sounds deadon.

By Attex Bob on Unrecorded Date: Edit

John: What # is your filter? My K&N filter book says it should be a #E-2540 or a #E2490. When you get it, please post the # so other AATV owners can enjoy clean air for their motors. About the muffler: Thats another tough question. I don't personally like super traps. They are very restrictive with their plate type system. I like flowmasters.......but they don't make a small engine muffler to my knowledge. You say that you have a motorcycle mechanic. They make some really really nice preformance mufflers for them. Talk to him and he will be able to set you up. Be sure he is knowledgeable about preformance engines and that it is type approved for where you are going to ride. George: I have a super Chief and my air box is fitted with a bellows hose that goes to the carb. My filter fits in that airbox. If I remember right, the air is ducted through slots in the back of the body. That is a good setup from the factory. It keeps the hot air out of the engine by ducting it from the outside. I think Richard has these bellows if you are missing yours. John: One more thing: I think it was Brandon that said that he uses split fire plugs in his engine, and he really liked them. I think this is another good idea. (thanks Brandon) It might give you just alittle more power? Can't hurt. All of these little "tricks" can really help the power situation out. I'm sounding like the tool time guy now...."More power". Good luck, and have fun......thats what these things are for!!!!!

By john prince on Unrecorded Date: Edit

Okay...won't get filter for a couple of weeks I'm told. My motorcycle mechanic kind of rolled his eyes yesterday and he fined tuned the Harley on his table, thinking why am I bothering to make a lawnmower go faster. But he's thinking about it, talked about kicking the governor up a bit, already adjusted the carb so I wouldn't lose fuel on steeper up slopes. I've got a couple of other guys to talk to this week who have run small engines in go-cart racing...see what they have to say. I'll post this and that advice I hear. I bet Richard knows all this stuff already.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Those are all good ideas but if you really want more uphill speed, the 14/16hp engine is going to need more than that. I did the mods to my engine because I wanted more wheel spin in mud and more accelleration uphill. The much higher land speed is only a good side effect!
You should just bypass the governor. I have found the stock 14/16hp engine can barely pass the 4000 rpm mark. Flat ground full throttle for several seconds and it might make it to 4000. You don't have to worry about blowing it up.
Bob, the K&N air filters might help a little but I doubt you would be able to tell the difference. You can run it with no air filter and that is about the change you will get with a K&N. Also, the K&N does not get cleaner air to the engine, just more air than other filters. It actually lets much more dirt through. If you run your 6x6 in very dusty places you are doing more harm than good.
You can get a lot of power with the stock carb but I prefer my Mikuni snowmobile carb. It is only $90 for a brand new one. It allows you to easily bypass the governor and it won't ever choke out on hills.
More compression: you can do that like I did by shaving the heads and putting on a thinner head gasket (or gasket only, less money and work but not so much compression). You can still run regular el cheapo pump gas. Lowest octane is fine.
I use Bosch Platinum +4 spark plugs (#4418).
Exhaust is where all the real power comes from. You can cut the muffler off and put on an exhaust tip like I did. If that is too loud, put about six bolts in a star pattern in the end of the tip. Now pack the tip with steel wool. The more you put in the quieter it will get. A quieter yet more powerful muffler... make your own cheap Flowmaster!

MaxRules

By john prince on Unrecorded Date: Edit

So what I hear out there is that if you run a "hot" muffler, or no muffler, you automatically heat up the engine, engine runs leaner(not necessarilly meaner). You have to open up the combustion side of the engine to allow for same. Haven't got definite recommendations yet except you don't do one without the other.

Another interesting tactic is to change gearing, either lower(if you want max power uphill), or higher(if you want flat speed). Now you don't have to mess with the engine.

By john prince on Unrecorded Date: Edit

A local guy who races Briggs/Straton on go carts looked the whole set up over, said change the sprokets at the chain, either more teeth for better lower end pull up the hills, or less teeth, higher gets better...and chain accordingly.

I'm running in a lot of dust...something to think about I guess with K&N. I like your cheap flowmaster idea. Maybe I'm just being too picky...I transported maximum load(600 lbs) up a 30% slope for a 1/4 mile...sure I was at the full rpm under that load but never really thought I'd falter.... Adjusting the float in the carb I have had no problem cutting out up steepest slope.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

That's not at all true John. Having no muffler will not make the engine hotter, it will get cooler if anything. It might lean it out a little but that can be easily made up by rejetting the carb. I had mine running so rich before that I will have to lean it down even more after taking off the muffler. Just look at the spark plug. Black - rich, brown - perfect, white - lean. Too rich will just make it lose power while too lean can damage the engine.
I did some heavy mods to the intake side of the engine before I did the exhaust. I already got a lot of power out of the intake side only. Fixing up the exhaust side was just icing on the cake.
On the other hand, Bill from Illinois (Bigfoot), has dual exhaust and stock carb. He hasn't done much of anything to the intake side and his Bigfoot really runs. Therefore, you can do one without the other.
Gear changes are really not a good idea. Gearing it higher might give you a good top speed but you really couldn't do any real off roading. It would take a big engine to even get it to top speed and to pull any kind of hill. Gearing it low would be nice for power, but aren't we already slow enough?

My Briggs turned 3650 RPM in thick mud today. It can finally throw a nice roost and clean out the tires. That is about 500 RPM higher than it could do with a muffler on it. Wow!

MaxRules

By Steve J on Unrecorded Date: Edit

Let me get this straight..You hack off the muffler, Hack the head, put on a thinner gasket, and change the carb. Ok Got that but why would you stuff steel wool in the muffler and restrict the exhaust flow you just created? Why couldn't you just by pass the governor using the stock carb and put a straight exhaust pipe on? John I can tell you this, if you up the compression and hack the muffler off it will be louder that a 2 stroke engine and you won't have half the horsepower. There are companies that make high performance parts for you engine. You can get the K&N filter, which does filter fine as long as you use the pre-filter oil recommended from the company. The oil helps pick up the fine sand and dust that might get by without. I would not recommend shaving the head. Some people talking on this page may have gotten lucky for the time being but these are air cooled engines, it is just a matter of time before something gets too hot. You might want to think about selling your 16hp engine and upgrading to a 20hp model.

Steve

By Attex Bob on Unrecorded Date: Edit

John: If you make the engine breath better on the exhaust side then you have to richen up the intake side......or you will get burn down!!!! Brandon: They run those air filter on everything in the Bahja race. Now those engines see alot of dirt!!! The people I've talked to say that they can supply more air and filter better than any paper filter. Look at some pictures of choppers in desert storm. See those big black things on the intake side of the turbin?? Those are K&N filters as big as a max!!!! Now thats a filter!!!! By the way Brandon; do you think you picked up any power with those plugs? And have you ever tried the split fires? You try more things then anyone on this forum and you would know. Also, tell me how you like that new carb. Do you feel that it gives you alot more power? Do you have any problems with it?

By john prince on Unrecorded Date: Edit

there's a local motorcycle specialist fabricator that does spectiality piping and mufflers. But my concern would be that I would be opening up the exhaust end without compensation at the other end. I was advised the engine would immediately run leaner and hotter, that I would have to compensate w/changes to carb etc, that it would be expensive, troublesome. changing the sprockett at the chain would be a better solution, either more low end or more high w/no changes to engine.

By john prince on Unrecorded Date: Edit

Best power improvement is to get the Bigfoot, replace the 9" rims and 25" rawhide III's with 8" rims and 22" rawhide III's. Now you have 18hp working for you instead of for bigger wheels.

By MaxRules (Brandon_price) on Unrecorded Date: Edit

Steve, the steel wool thing is for those who want more power with less noise. You can take off the stock muffler (which has way too much restriction), and quiet it down with the steel wool. The more you put in the quieter it gets, but you will also lose some power.

"If you up the compression and hack the muffler off it will be louder that a 2 stroke engine and you won't have half the horsepower."
This tells me you don't have a clue what you are talking about. I happen to own a 440cc 2-stroke in a Hustler. My Briggs could never match the tremendous noise level of the 2-stroke.
I raised the compression and hacked off the muffler on my Briggs. Strange how it got more powerful and faster than ever before. Biggest and cheapest horsepower gain you can get. Experience knows all.

K&N filters do let more dirt in than other filters. It probably won't ever hurt your engine but it's still eating dirt. I've seen it in tests. You can do your own test by putting a small dab of grease right inside the carb intake. Run the stock or other good quality filter in a dusty enviroment. Now look at that grease mark and see how much dirt is on it. Do the same with the K&N and you'll see just how much more dirt gets by.
The Bosch plugs mostly improve throttle response.

MaxRules

By johnprince on Unrecorded Date: Edit

Sure would like some consistent advice on what to do about a 16hp engine(besides replace it). Guess I'll do K&N, Bosch plug, see if that provides any worthwhile tweek. What are you setting governor to? As for intake vs exhaust changes, everybody has a different story.

By MAXEUROPE on Unrecorded Date: Edit

John - I've read with the posts above.

Everybody is right in their own way.

My view is as follws:-
The Briggs engines (con rods) are fine up to 6000rpm. If you take the governer off (don't forget to fit a positive retun sping if you do), the way the valve springs are set up you'll only get 5000rpm anyway. Trick is to shim the springs to get the extra 1000rpm. Try using bolt on mods to start with - you want to get AIRFLOW - i'll say it again AIRFLOW. If you want to stay 'stock', change your carb for the double barreled carb as used on the 20hp vanguard (part no. 808278 - and adjust the jetting for best power), K&N Filter, Bosch +4's BUT MOST IMPORTANTLY - change the exhaust. I run a double 'Supertrap IDS2' setup with a dead straight large bore (2")from the stub manifolds. There's no reason why you can't use a single can - just make sure you pipe work is as straight as possible. The high flow muffler is the key to power gain. Sure it'll never be 'quiet', but we're doing lots of trades here. With all these bolt on Mods there's no reason why you shouldn't increase your power by at least 20%.

These mods are easy and reasonably inexpensive. To go furthur why not port and polish, regrind the cams, balance the crank, lighten the flywheel - this is where it'll run into 1000's not 100's - BUT, I've had a measured 22% increase in power on my 18hp with bolt on mods and a 60% increase with my 'special' treatment.

OK, we are going to trade engine life and reliability in the long run by doing any of these mods, but is the trade worth while on a block that's so 'bullet proof' anyway?? Personally I think so!!

Modify and enjoy - release the power of the choked Vanguard!!

By Steve J on Unrecorded Date: Edit

Brandon,


I think you are the one who does not know what your talking about. I have seen go-carts that have 30HP and go 50MPH that are as loud as a 350 chevy! I have a 440 Argo and used to own an Attex to. Both machines were much quieter than the modified Briggs and both engines had much more HP. You prabably hacked the muffler on the Hustler too and forgot you did it!!! hahaha.

Steve

By john prince on Unrecorded Date: Edit

MAXEUROPE

I printed out your advice, will add it to the stack of letters/notes that I heap on mechanic's head. There is a custom muffler company here in my town for motorcycles...ships worldwide. From what you are saying, you can't just do the muffler alone without opening up the other end(at least carb)?

By MaxRules (Brandon_price) on Unrecorded Date: Edit

The comparisons you make have nothing to do with my Vanguard engine. I don't doubt the go-carts would be very loud. My Max is not a go-cart. Those carts are probably modified to put out up to six times more HP than stock and run the track one time. I can put my Hustler 440 right beside my modified Max. The only thing you can hear is a very loud and annoying 2-stroke.
Come to the Badlands ride and I'll show you.

MaxRules

By MAXEUROPE on Unrecorded Date: Edit

John

There's no reason you can't sart at the exhaust.

The stock muffler is probably the worst design ever!! Straight 'T' joints and small bore just chokes the engine.

No reason in trying from this end - you won't get any bad results!!

By john prince on Unrecorded Date: Edit

maxeurope...can you buy a muffler out there at some online parts house or catalogue?? Got any suggestions?? I can get the pipe work done locally, and could go to this custom motorcycle place, but it would be better to hear which one to buy for a 16hhp?

By Bill Davis (Nvbigblue) on Unrecorded Date: Edit

Hello all. As a new MAX owner (new owner, old MAX), I have a couple of questions for the group. My MAX (unknown year) came with the Rockwell JLO 297 2-cycle engine. The previous owner removed the original carb and replaced it with a Keihn carb. It runs like crap, pukes fuel out the bowl overflow tube (into a 7-UP bottle!) and vibrates like crazy. I've only been able to drive the machine for about 10 minutes total since I bought it. And the fuel thing scares me as well. Sooooo....I found a Briggs and Stratton 18HP I/C twin cylinder engine for $325 (nearly new, 260 total hours). This isn't the vangaurd "V-twin", it's a flat twin. I'm wondering if this would be a decent engine for my MAX. I don't want to fly down the road, but I would like plenty of power for hills and such. I live at 4600' and most of my riding will be above the 5500' level. Has anyone out there used this engine before? It will be tight, but it will fit. Other than changing the drive clutch, what else should I worry about? Oh ya, I paid $750 for the machine, did I get ripped? I looked at one a couple days earlier that had a B/S 12HP AND tracks for $2500. But the body was torn to bits. Thanks for the help guys.

By MAXEUROPE on Unrecorded Date: Edit

John

My setup is 2 Supertrap IDS2's with straight pipewortk from the manifold to the back of each can. I made this myself - it's easy to do.
The cans are universal. The stub manifolds bought as a spare part from Briggs, and the pipework and support bracketry I did myself - easy!!

www.supertrapp.com/MotorcycleATV/atv/3inch_Ids_main.htm

Or just get your exhaust man to make one!!

Hope this helps

By mr. tinker on Unrecorded Date: Edit

bill,

i have a mid 70's max IV and it had a two stroke engine originally but was factory converted to a briggs lhead 18hp engine like you have.it looks like you have a maxII from the pic in profile.the maxII engine location is different from mine but im sure it will fit in there.be nice if you had another one to look at and see how its mounted.my exhaust is both sides going to what appears to be a expansion chamber and then to a small car type muffler then out the back.you will need to do a little modifying on the throttle hookup but mine still uses the governor. could send a pic of that if you need it.also make sure you use pulse type fuel pump not electric like somebody put on mine that i promptly removed.real fire hazard if you get a leak.

By mr. roadwolf on Unrecorded Date: Edit

bill davis, sounds like your float is set too high, kehin carbs are excellant "carbonators". get a good rebuild kit from a snowmobile or a motorcycle supplier and do your max a favour.

By john prince on Unrecorded Date: Edit

MAXEUROPE so you think I can just change out a muffler system without any other modifications and get better results?

By MAXEUROPE on Unrecorded Date: Edit

John

Yes. Essentially the stock muffler does the same for the engine as trying to breath through a pillow!! Free the airflow and you'll feel the power - it's the muffler that causes most of the obstruction.

I did all mine at once, but there is no reason why you shouldn't start at the muffler and work back. If I had to choose between any of them I'd Definitely change the muffler first.

Just make sure you get a nice high flow system. As I said before it'll never be quiet, but you'll be amazed at the increase.

Just make sure you try and do the others to get the full benefit as soon as possible. There are all sorts of carbs on the market. I went for an uprated Briggs just because I new it would fit and it pretty much guarantees a 10% increase in power straight off.

By Bill Davis (Nvbigblue) on Unrecorded Date: Edit

Mr. Tinker: Thanks for the info. A pic would be handy if you've got one. I dug through my parts bin and found a nice little pulse pump off a quad. I think it will work great.

Mr. Roadwolf: I thought that's what it might be too, but I already adjusted it lower. I really think it's the fact that the engine jumps all over the place causing the float to bounce. I torn down the engine today and had to re-gap the points and the timing was too advanced as well. I'll try to get it running again tomorrow. If I can get it to run well enough, I'll keep the 2cycle, otherwise it's out the door. Any thoughts on what the proper mixture for that engine would be? I've been using 32:1 to be safe, but I think that's a bit rich.
Thanks.
Bill

By liflod (Liflod) on Unrecorded Date: Edit

If you go to Briggs and Stratton's web site, there is a very interesting article about modifying a stock 5 HP engine and how much power is gained through the modification process. I will search for the link and post it.

By john prince on Unrecorded Date: Edit

uprated Briggs...can you point me to website or model?

By MAXEUROPE on Unrecorded Date: Edit

John,

The Carb I use is the twin barrel Briggs (part number 808278)- your local dealer shoud pull it right off his screen.

I used the word uprated just because it's better than the stock carb on the 16 & 18 vanguard. It's the standard carb that's on the 20hp vanguard.

The 18 & 20 vanguard blocks are IDENTICAL apart from the carb. Single barrel on the 18, double barrel on the 20. Simple maths - 10%ish power increase!!!!

By Brian whoeler (Victhedog) on Unrecorded Date: Edit

whats the easiest way of removing the govenor
looked at my 18hp max but didn't know what to remove?

By ARGOGERU on Unrecorded Date: Edit

HOW MUCH FOR THAT DOUBLE BARREL CARB IN DOLLAR AMOUNT THEIR MAXEUROPE?

By liflod (Liflod) on Unrecorded Date: Edit

http://www.briggsracing.com/tech_tips/briggs_stocker_blueprints.html

This is the site about blueprinting a stock 5HP Briggs engine. If it works on a 5HP it will work on a larger one. If you are thinking about modifying a Briggs check this site out.

By john prince on Unrecorded Date: Edit

MAXEUROPE

So I have the 16hp. Can you put that 2bar on the 16?

By MAXEUROPE on Unrecorded Date: Edit

John,

I would say 99% yes as all the main block components for Vanguards are the same.

Just check with your local briggs dealer to get the carb manifold dimensions to check.

You'll need the part number I've posted plus the numbers off your engine plate which is on the t-20 side of the block.

I pay £160 (UK) for the carb from my briggs dealer but have no clue what they are anywere else.

The best way to take off the governer is to get a work shop manual and read or take it down to the dealer. There are lots of spings and brackets to describe on a post that could lead to someone taking the wrong one off!!

If you guys want, let me know and I'll take some digipix and post them of the correct ones to do.

By Ted Stanfield (Ted) on Unrecorded Date: Edit

More Power Modifications: try www.hscsupercharger.com for Briggs superchargers and www.briggsracing.com for factory hotrod parts.

By john prince on Unrecorded Date: Edit

Have handed all this information & manual to my mechanic for his input. I'll post feedback & what I attempt to do.

By john prince on Unrecorded Date: Edit

checked out www.hscsupercharger.com; interesting but price & labor to install on top of still needing to open up exhaust and recommendations that the engine would need rebuild(blueprinting) sends one in the direction of a new engine or next model up.

By Brian whoeler (Victhedog) on Unrecorded Date: Edit

MAXEUROPE

ORDERED THE MANUAL BUT STILL INTERESTED IN THE PICTURES I THINK ALOT OF US WOULD LIKE TO SEE THE CORRECT WAY TO GO ABOUT THIS

By john prince on Unrecorded Date: Edit

My mechanic was rebuilding a Harley while I was showing him all these gadget add-ons for a 16hp Briggs. He no doubt thinks I'm a little daffy trying to get a bathtub to go faster.

By MAXEUROPE on Unrecorded Date: Edit

Thanks John,

Had a good laugh over that!!

By Brian whoeler (Victhedog) on Unrecorded Date: Edit

have the manual still need to know which spring to remove ? they all look to be return springs?
what if I just remove the blot that connect the govenor the the shaft that comes out of block?

pictures would be great