Register Community Calendar Today's Posts Search

Go Back   GZ 250 Forums > GZ250-Specific > Instructional Articles

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 02-15-2007, 01:37 PM   #11
Jordan310
Senior Member
 
Join Date: Feb 2007
Location: Los Angeles
Posts: 122
After conversing with several very knowledgeable people en here on this board.on this board, and with the EDGE motorcycle club in Lawndale, California, I proceeded to complete some mods described here on this board.

1. The Free Flow Air Filter Mod

This modification did not require a K&N, or any other aftermarket filter. I will eventually get around to replacing the modified stock filter to a K&N, but in reality, not much improvement as far as horsepower would be gained. Looks wise, yes, performance wise, .. not really. So I removed the seat, took a look at the restrictive airbox, and proceeded to find an easy way to remove it. I found one - A big hammer. After (very carefully, and after removing the air filter) smashing the crap out of it, it slid quite nicely out of the frame (in a few pieces). Ok, so with that done, I looked at the rubber connecting tube that once led from the carb, to the airbox. Ok, so it looked as though I could take the stock air filter and place it flush against the rubber piece. There are 4 little nubs on the air filter where the diverter piece used to be. I sliced them off with a razor so that the face of the filter was flat, and would sit against the rubber hose flush. If you don't do this, you WILL get some leakage, a good seal wont be made. I then wedged the air filter in-between the carb, and the toolbox/storage compartment, and tada! a free flow air filter. =)

2. The Holes In The Stock Exhaust Mod

Ok, so all looked good, I put the seat back on, proceeded to clumsily drill 8 1/8" holes around the outside ring of the baffle plate on my stock exhaust.
I hit a sort of flange cutting into it, but didn't cut through it. In any case the holes were in, and my 1/8" drill bit, and 9v drill were exhausted. I promptly returned them to home depot =) ... and then ran back home. Turning the engine on, I got a roar. not a tiny one, but a good sized growl. Wow. All I can say is wow, what a difference. But I did get a little popping. It sounded great overall however, and concluded that this mod was worth it. I considered de-flanging the pipe, but was advised my a great motorcycle mechanic against it. Not enough back pressure, an odd sound, and just not worth the trouble. I think for now I'm fine with this until I get a new bolt on pipe all together.

3. The Carb Adjustment

Well, it was time for the test ride, and WOW. After riding this new set up, .. it ran like ... Shit.
Literally a piece of dung. In fact, it seemed to change the way everything ran altogether. Not great. It was running way too lean, and this was not good at all.
Taking it to Edge Motorcycle Club in Lawndale, Ca fixed all of this. In an hours time, my buddy opened everything up, and proceeded to modify the carb.
Now I described what many have said on this board as far as how to rejet their carbs, and went into detail as to how he should go about it. The only problem is, that the carb needle was stock, and did not have grooves to move the washer, or slider down into. If I would have had a jet kit, this might have been different, but it was stock, so he decided to do a few other things. First, he drilled out the main jet to make it a 150th jet. He then adjusted the air screw to tune the pilot jet circuit. He had to make several holes where there weren't any, to access the adjustment screws, but he decided that this tune would be just fine and didn't require the needle adjustment.

Now came the road test. He started it up. Woosh! Vroom! MUCH DIFFERENT. The bike, I kid you not runs MUCH better than stock, my top speed has increased from a stock 55-65 to 65-70. The power boost is amazing, and It is a much better ride in every way. I am impressed. Wow.

The next mod I was suggested to give it was an upgrade from a 15 tooth front sprocket, to a 16 tooth. With this upgrade, I will gain a better top speed, and the loss of low end power will be so slight that wouldn't matter. Especially for a 250cc bike. I'm told I should hit 75-80 after the sprocket mod, a K&N, and a new pipe. This is good enough for me, as I will be riding this on the highway in Florida where the speed limit is 55mph. Most people cruise at 65. That's all right with me.

Removing The Rear Seat Mod:

Too easy to explain.

I do ahve a question. Does anyone know of the largest, and best K&N to use on this bike, the size needed, and any adaptor hose used?
As well, what bolt on pipes would look/work best on this fun little bike? I have head a lot about straight pipes, and others, but can anyone reccomend a few? I dont want it much louder than it already is now, and it does not need to be a Harley, but some more free flow, as well as a deep rumble sound as opposed to a 250cc sound would be awesome.

Anyone?

Thanks guys. =)

I love my bike, and as a fist time rider, Im already outgrowing it. My next bike I think is going to be the Suzuki M50 for sure.









Login or Register to Remove Ads
Jordan310 is offline  
Reply With Quote
 




Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:52 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.