different exhaust on a g9

[KFX700#319]

I was wondering if anyone has put a different exhaust on a g9?...I have my stock exhaust from my kfx 700 and it looks like it will mount right up to the engine the flanges look the same. would this make the engine run better and what kind of jets would be in the carb because it will probably need rejetted? just looking for some opinions on this..thanks

[sho305]

Lots of people have, many put a motorcycle muffler on them. It should flow better and might require a richer jet in the carb. You can also improve the intake side, and if you are do them both so you only have to jet once. Far as power it does not do much, I mean even if you pick up 10% that is one HP but I doubt it helps that much.

[rokcrlr]

Taking the stock muffler off a 5hp briggs and adding a header will make a 20% power boost.We take the 6.5 clones ,throw the stock exhaust and air cleaner away. Add a header , K&N style air cleaner, rejet and reset the valves to 0 lash cold and they almost double in power ,up into the 10hp range. I don't see why these engines would be that much differant.

[sho305]

Well, try it. Part of the issue is except at max speed the engine runs on the CVT at say 2500-3500rpm, so only a power increase there will affect how the cart runs. Sure you can wind it out to 4500+rpm and maybe you get a couple more mph out of it if you wait long enough. People been messing with these things forever and the only way to get significant power is a cam, and you have to have that specially made. Sure you can get a little it just makes a limited difference, its real hard to tell. Not that there is anything wrong with fiddling with them, it is fun. Problem is you buy some parts and next thing you know you could have bought a new clone 16hp that will blow it into the weeds, but yes you have to fab stuff to install one. Your gokart/minibike its all about rpm while the cart at 30mph on 22s is all tapped out looking at 5K and has nothing left at that rpm and more drag. I've spent my hours on the 4cycle forums looking for info but with a cart you need 2,000-4,000rpm power for most things, that means torque. A 16hp clone smokes the tires on a kart, but in a GC its just enough to spin some up a hill with 22s. I hate to sound like a jerk if I do, its just that nobody has every come up with much with a stock engine in a yamaha 4 stroke. I've been on this site for a while and BU for years before that. A couple times someone did build up a stocker, but at great cost that was not worth doing for the rest of us. Of course for some it would be worth it to make it sound different, nothing wrong with that. Unfortunately where I ride I have to keep it quiet, what I really need is a valve in the exhaust....

[rokcrlr]

Then you should get one of them new engines Plowman has, A rotary, them you could go HMMMMMMMMMM, instead of GGGRRRRRRRRRRWWWWW. Just funnin ya,Yea the cams are pretty lame on these

[sho305]

I'll have to check that out not been on plowmans site in a while. He has some great stuff no doubt, but it can add up. This clone I did has about double the power and runs near exactly like the stock engine, starts the same, tops out near the same. I want to try to get a little more rpm out of it. But now it has enough power to spin up dirt hills and loft the front end over the top, a stock cart (I compared) barely crawls over the top of the same hill. (a steep ditch about 6'+ high). Have <500 into it, had to make the mount on the stock one, used the stock clutch and generator and that is an electric start in case we want to use it later. On top of all that this cart blew the oil ring and it was something like 700 for a rebuilt block from the dealer if we installed it. Yeah I could have rebuilt it myself but hey, hp is king lol.

The nice part about putting an exhaust on your G9, is you can mod it to fit a larger engine later. I hogged my airbox out and rejetted, I did try a muffler once but it didn't seem to do much and was too loud. Working on the clutches seemed to help more than anything.

[KFX700#319]

Ok so from whst i am seeing om here putting the other exhaust on the stock engine is not gonna do much as far as power gain...just make it sound better..dont think i am gonna do it then....atleast not now. ....I am gonna look into getting a bigger engine in summer ot next winter thanks for all the input..

[sho305]

My guess is it might help your top speed a little, but I've never seen any proof of anything pro or con....so I don't know. I do know you can put a different intake filter and exhaust on it and it is hard to tell a difference. I hogged my airbox took the silencer off and hogged the jet and I always raced another cart, it made hardly any difference but might have helped top speed a mph or something. That was with stock muffler.