My G14 Experience in Modding

[hiatt65]

Hey fellow members i thought i would chime in and tell everybody what i have done to my cart and what i have found to be beneficial. My findings are not an exact science because i did not do any tests before the changes, but are pretty much by the "seat of the pants" opinion and GPS facts. First thing is i bought my cart stock straight off the course and built it to a 6" lifted, 22" tire wheel combo, back seat installed, custom painted, plowman carts performance kit, equas tach, grant steering wheel, all sports short windshield and rocker panels, brush guard with lights, k&n filter with filtered crankcase, modded engine,---- fun mobile! Sorry i went on so long but i wanted you to get the picture of what i have installed on my machine Like any other guy i wasnt happy with the stock performance, so i started my endeavor to build a better machine. I have pretty much built up every small engine toy i have ever owned, lastly being my 2006 Polaris Ranger 700XP. Anywho, for my first performance upgrade i talked with Don Plowman(very acknowledgeable Yamaha guy) and he recommended his performance kit which consist of the shaved secondary clutch with new spring, new main and pilot jet, and of course the performance exhaust. With this kit installed i gained good hill climbing ability and a top speed of 26 mph. Not bad, but not good enough. I could do the "big block" engine, but i really didn't want to get away from the true "Yamaha Experience". I wanted to stay with the stock engine as long as there was power to be gained from it. The engine was tore down, the head was sent to the machine shop for a .025 mill job and polished ports, the cam off to California for a torque grind, and the pick up coil adjusted to some kind of advance(not sure of the degree). A K&N filter and prefilter was added along with more hogging of the main jet. Tried to index the plug but the threads were not allowing it. With the Plowman's kit i noticed an increase in torque and some throttle gains throughout the rpm range due to increased exhaust flow, but no difference in top end. Now with the modded engine, there is a noticeable(seat of the pants) throttle response throughout the rpm range with a "pulling feeling" all the way to the top speed of 32 MPH!!!!(GPS) That is a 6 mph gain people. My equas tach for some reason is acting faulty, i didn't have it on before the mods but after the mods, so i cannot compare rpm readings. Still working on that issue. But as far as wanting to keep your original engine and stay yamaha, it can be done with noticeable gains. The total price for just the internal mods for me was 160.00. Just letting the people who want to stay original know. Thanks--If you want to see a picture of my cart look under the thread "Say hello to black magic".

[Mike Mac]

Hiatt, very interested!! Want to know more about the cam! Where and how much!

[smallblock450sl]

Did you do anything with the valve springs? Heaver replacements or shims? Would hate to have valve float with a larger cam grind and higher rpm's.

[hiatt65]

Mike i sent you a PM. Smallblock, i kept the stock springs for now because i was unsure of the rpms i would be reaching. I wasnt even close before the mods even with the govenor disconnected. My tach right out of the box, set to 500 rpms will read around 2500 running at idle. If i set the tach to 1500 rpms it will read around 800 rpms at idle and around 3000 rpms at full throttle, so im not sure what is wrong with it or if im doing something wrong. Anyway, choosing the later setup in nuetral i can start to hear the valves wanting to float at around 3500 rpms, so im shy 500 rpms at full throttle. In other words tach working or not working i still have around 500 rpms to go before valve float, which i assume realistically to be around the 4500 rpm range. What are your thoughts on that?

[Doug c]

How is the volume on the performance exhaust? How much louder is it than stock?

[hiatt65]

The exhaust is not any louder then the stock one......it is a plowman's exhaust.

[sho305]

I think its great when people mod carts, whatever engine. Its my experience the cam is the largest factor holding the stock engines back plus poor flow through the head. Unless you change gearing or tire size, you need more rpm to get more speed. Some have ported the head and welded them back up (where they ported out the side).

I would tell anyone to put a clone in if they want power, but rpm is about the same far as top speed unless you do gears or larger tires like 25 or better which are difficult on some yamaha. But its some work putting it in you need to fab up a lot of stuff, the plumbing itself is hard enough. It will do a donut from a dead stop, toss a huge rooster off one tire in dirt, has around twice the power I'd guess. But it shuts down at speed and runs around the 30gps my G9 will do it just gets there much faster. The block/head/carb is completely stock on this one aside from no governor, so more rpm might be had with some mods which I plan to do when I put one in mine. I'd say its doing around 5K rpm.

The clone is cheap as dirt, but a v-twin is larger and will rev higher they do 6K no problem with a cheap rev kit, have more power yet and cost a lot more new. The clone you really need a flywheel, rod, cam, springs to get more power and rpm. It might have more power than a stock v-twin but possibly the same money by then. This was the 420cc.

On the other hand if you mod a stock engine you don't have to fabricate a bunch of stuff, its a lot less work.