UPDATE - New K&N Filter, Emgo Muffler, and Carburator Mods

[masterkeosk]

Sounds like good advice, thanks guys!

[dannylightning]

if you buy the jet for 10 bucks and do it your self witch looks really easy, it may be worth it if and if you don't mind a bit less gas milage.. there is a great how to on this site for this mod and some other things to increase power..


viewtopic.php?f=8&t=617..

[David Bo]

Here is the reality... My new jet cost $2.99. I bought a new one with a 145 oriface. I also spend about 30 cents on two new brass washers for my shim mod. By the time I drilled out that little plug out of the bottom of my carburator to get to the IDLE screw, did the needle shim mod, and replaced the jet, I probably invested about 45 minutes of time into this modification. $3.29 and 45 minutes to gain 5 to 7% horsepower ain't too bad.
Now, I did replace the exhaust system last weekend which took about 1 hour or so. I also bought a new K&N Filter. That total came to about $125.00 so I guess I am actually up to just under $130.00. I am not a big fan of highway driving. I get nervious going faster than 60 MPH on my GZ. I feel as though the bike is too light or something and sometimes it feels like I am going to fly away (does anyone else get that feeling?). I do, however, notice a big difference in the acceleration of the bike. I can get up to 40 or 45 mph much quicker than when the bike had all stock parts.
Yes, Blackbird, I did re-install my 16 tooth sprocket. That seems to help with the acceleration and "easier cruising speeds" as well. All and all I am VERY happy with these modifications... -Dave Bo

[mrlmd1]

Does anyone actually do time trials or runs with a good stopwatch or dyno testing to see if these mods really give the claimed improvement? Everyone says "I notice a big difference", "it has much more power now", etc, etc. How much of this is real and how much is the louder exhaust and poorer gas mileage and ego involved in reaching these conclusions? If all those mods gave a 5 or 7% power increase, do you get 5 or 7% faster acceleration, or how much, what percentage increase do you get, and how much do you shorten the life of the engine by increased wear, and by how much do you decrease the resale value of the bike when the next owner realizes you are screwing with it to get it to go as fast as you can? I'm not criticizing anyone who does this, after all I have Saw boxes for bags on my bike, I'd just like to know. Do you think you are really improving on the Suzuki engineers who designed and developed this thing? If they could get 22hp instead of 20 out of the engine without seriously diminishing it's life and reliability, don't you think they would have done that? Would be a great selling point to have that increase in power at no real downside cost. I'd just like to see some objective data that shows that this effort and expense accomplishes something.
The 16T sprocket is another story, some like it, some don't, depends on riding style and use of the bike.

[David Bo]

I am one who personally does not give a crap about the resale value... I bought this motorcycle as a toy and I always liked to tinker with my toys . I only use top quality FULL SYNTHETIC engine oil (currently running with Royal Purple 10W-40). I also don't think the modifications I did are all that drastic.

On your question about why Suzuki does not make all of their GZ 250 bikes with full blown horsepower... I think all of the bikes that come over here to the US from Japan have to meet up with the high "California Emissions" laws. I am not an expert on this subject but why else would they send them here with tiny exhaust pipes and "air intake reducers" on the GZ air filters? As many people have mentioned in previous posts - the stock GZ's run VERY lean... It must have something to do with less emissions coming out of the exhaust pipe to meet the high California standards. I don't think Suzuki makes "special motorcycles" for the state of California and "regular" motorcycles for the other 49 states. I'm sure they think of us as one big bunch and make their bikes to met the emission standards for the whole country.

Finally, the idea is to have "fun" on your ride... If the modifications that I and some of the other guys on this forum have made means that the engine life will be reduced to 35,000 miles instead of 40,000, so what? I believe in quality not quantity... When my bike reaches 35,000 miles and breaks down, I will cut it in half and make two kick-ass wheelbarrows !!! :tongue:

[mrlmd1]

There are different emissions equipment on CA bikes - refer to to other threads on here about their canisters. And one bike in Spain has a possible EGR valve on it. There are a number of different bikes for different countries/states.
And lean may be on purpose, for fuel economy and compromise of power/displacement etc. I am aware of that. And what is this lean compared to, other bikes, to how rich it can be made? Was it not designed like this? The bike is what it is. I'm not trying to start an argument, I'm asking a question -
I was asking if any of these mods have objectively been shown to produce any HP or power benefit of significance, other than the owner's subjective perception. I have no problem with anyone doing any mods to anything they own, I would like to know if they really work and how do you know? Just by the throaty and louder exhaust which can be measured by your ears, or is there another way to prove what you are doing works? Not such a hard question to answer.

[marmar1982]

Ok.. so I just got my GZ and it REALLY needs some sound.... help me with a loud exhaust for it!

[dannylightning]

Originally Posted by marmar1982

Ok.. so I just got my GZ and it REALLY needs some sound.... help me with a loud exhaust for it!

so far all the pipes i have heard sound clips of sound terrible. they still sound like deisel tractor or something chugging down the street to me just a little louder and a little different tone. but still just go put put put put put put put put put. i did hear one piple that sounded more like one of those sport compact cars but unless you get a bike with a twin it's probably never gonna sound good. i did not know that when i got my gz. i wanted some sound to mine too but i give up on that. dont think it gonna happen. plus it sounds like you need to rejet and all that to to make the bike run right after installing a muffler with a large diameter hole..

[music man]

Originally Posted by marmar1982

Ok.. so I just got my GZ and it REALLY needs some sound.... help me with a loud exhaust for it!

It is also not gonna get you anywhere to post the same question over and over again in different threads, the answer is not gonna change if you do that, I promise .

[David Bo]

mrlmd1 - I guess the best way to find out is to try them out on your own machine and then go for a ride. Everything that I did on my bike is reversable (except for the new exhaust I guess). I am certainly not an expert but I do know enough about carburators to know that if you have a greater quantity of air and gas of going into the cylinder, more power it will produce. But, of course, there is a limit. That is all we are doing with these mods, a little more fuel going in and a little less resistance going out. I know this bike "is what it is". I just feel that these simple modifications can "tweak the performance" a little bit... I certainly do not have a Dyno Tester to prove anything.

As far as the gas mileage going down- yeah, I am sure it has. But again, that is not as important to me as it might be to the next person. I also feel that running the bike with the throttle constantly wide open may, over the course of time, be harmful to the engine if a person should go ahead with all of these mods. I wouldn't recommend over doing the throttle action all of the time. Anyway, I finally got up the courage to do all of this stuff on my machine and, so far, I am glad I did. - Dave Bo