cylinder head mod! carb mod! muffler mod!

pentax2 · 02-17-2010, 05:51 PM

This is my first bike a 2001 gz250.

And after a few months I decided to start making some changes, most of them came from this great site. (Thanks, very well done!).
Here are some of the things i have done:

-16t front sprocket.
-new exhaust, or as I call it "sound system".
-alarm system.
-free flow air filter.
- A much needed carb mode due to the exhaust and filter mods…

And it's great it really made a difference !!!

burkbuilds · 02-17-2010, 06:32 PM

Great looking bike! Tell us about the "differences"! A lot of folks mess with this model often with exhaust mods, carb re-jetting, etc, but most report that it didnt' make a lot of difference in performance. So what significant differences did your mods make? Like, are your zero to 60 times faster, do you have more top end speed, does the bike handle hills better, changes in fuel economy, stuff like that. If you have actual specs that's even better, but just your impressions would be good to hear if nothing else. Thanks for sharing, and by the way, how about telling us exactly what those mods were, like what exhaust pipe did you go with and what exactly did you do to the carb and the air intake? Even stuff like, how much it cost you to do this and how much time/trouble it was to do the mods would be appreciated, thanks.

pentax2 · 02-19-2010, 02:02 PM

Well the first thing after buying it was to change the cylinder head because I bought mine with a cracked one… I bought a racked GN250 and took its head…

The second thing I did was the 16t front sprocket- made a noticeable difference in long cruses. It improved the fuel consumption to from 27(km/l) to about 31(km/l) (63.5 mpg to 73 mpg).
But the acceleration suffered due to the longer gear ratio, overall it's worth it.

The third thing was the "sound system" aka free flow exhaust no change in performance but a huge difference in the "look at me I'm driving a thunder" effect.

The forth thing was an alarm system nothing to say about it, it works.

The fifth thing was the free flow air filter and crab's main jet replacement (took a while to find the right one, 130 in my case) the bike became edgy (in a good way) and more responsive and another cool sound was add from the crab over 3/4 throttle open (sound of the engines breath).

pentax2 · 02-19-2010, 02:27 PM

But the last mod was the biggest one, during the overhaul I performed on the engine (due to smoking and "oil drinking" from the engine) I decided to port the cylinder head, it improved the fuel consumption further to 35 (km/l) (82.3 mpg).
I took some photos of the process:

pentax2 · 02-19-2010, 02:47 PM

And now the after:

bonehead · 02-19-2010, 02:50 PM

What did you use to port the head?

pentax2 · 02-19-2010, 02:57 PM

and the installation:

pentax2 · 02-19-2010, 03:02 PM

I used two similar tools for the job one the first is a micro air grinder and the second is regular air grinder.

burkbuilds · 02-19-2010, 03:24 PM

Great pictures, amazingly clear details! Thanks for sharing your work on the engine, nice job!

pentax2 · 02-19-2010, 05:36 PM

I'm glad i can share it with people who can appreciate the work that's been put in to this bike.

02-17-2010, 05:51 PM	#1
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	cylinder head mod! carb mod! muffler mod! This is my first bike a 2001 gz250. And after a few months I decided to start making some changes, most of them came from this great site. (Thanks, very well done!). Here are some of the things i have done: -16t front sprocket. -new exhaust, or as I call it "sound system". -alarm system. -free flow air filter. - A much needed carb mode due to the exhaust and filter mods… And it's great it really made a difference !!! Login or Register to Remove Ads
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02-17-2010, 06:32 PM	#2
burkbuilds Senior Member Join Date: Mar 2009 Location: Shannon, Georgia Posts: 1,268	Re: A 2001 gz moded to the bone... Great looking bike! Tell us about the "differences"! A lot of folks mess with this model often with exhaust mods, carb re-jetting, etc, but most report that it didnt' make a lot of difference in performance. So what significant differences did your mods make? Like, are your zero to 60 times faster, do you have more top end speed, does the bike handle hills better, changes in fuel economy, stuff like that. If you have actual specs that's even better, but just your impressions would be good to hear if nothing else. Thanks for sharing, and by the way, how about telling us exactly what those mods were, like what exhaust pipe did you go with and what exactly did you do to the carb and the air intake? Even stuff like, how much it cost you to do this and how much time/trouble it was to do the mods would be appreciated, thanks.
	0

02-19-2010, 02:02 PM	#3
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... Well the first thing after buying it was to change the cylinder head because I bought mine with a cracked one… I bought a racked GN250 and took its head… The second thing I did was the 16t front sprocket- made a noticeable difference in long cruses. It improved the fuel consumption to from 27(km/l) to about 31(km/l) (63.5 mpg to 73 mpg). But the acceleration suffered due to the longer gear ratio, overall it's worth it. The third thing was the "sound system" aka free flow exhaust no change in performance but a huge difference in the "look at me I'm driving a thunder" effect. The forth thing was an alarm system nothing to say about it, it works. The fifth thing was the free flow air filter and crab's main jet replacement (took a while to find the right one, 130 in my case) the bike became edgy (in a good way) and more responsive and another cool sound was add from the crab over 3/4 throttle open (sound of the engines breath). Login or Register to Remove Ads
	0

02-19-2010, 02:27 PM	#4
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... But the last mod was the biggest one, during the overhaul I performed on the engine (due to smoking and "oil drinking" from the engine) I decided to port the cylinder head, it improved the fuel consumption further to 35 (km/l) (82.3 mpg). I took some photos of the process:
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02-19-2010, 02:47 PM	#5
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... And now the after: Login or Register to Remove Ads
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02-19-2010, 02:50 PM	#6
bonehead Senior Member Join Date: May 2009 Location: elgin,tx Posts: 907	Re: A 2001 gz moded to the bone... What did you use to port the head? __________________ Standing with the PGR until they stand for me.
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02-19-2010, 02:57 PM	#7
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... and the installation:
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02-19-2010, 03:02 PM	#8
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... I used two similar tools for the job one the first is a micro air grinder and the second is regular air grinder.
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02-19-2010, 03:24 PM	#9
burkbuilds Senior Member Join Date: Mar 2009 Location: Shannon, Georgia Posts: 1,268	Re: A 2001 gz moded to the bone... Great pictures, amazingly clear details! Thanks for sharing your work on the engine, nice job!
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02-19-2010, 05:36 PM	#10
pentax2 Junior Member Join Date: Nov 2008 Location: israel Posts: 9	Re: A 2001 gz moded to the bone... I'm glad i can share it with people who can appreciate the work that's been put in to this bike.
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