GZ250 power increase. - Page 4

trykemike · 03-02-2009, 12:32 PM

Hey Quimrider re: the "choke" use your tach for this test. When the engine is warm and at idle
with the choke off move the lever slightly until the rpm just starts to increase. Take a test ride
it may/may not improve the performance. I have the spot marked so I use it on most cooler days and when I run on the freeway because acceleration improves on my bike. Try it.

:??:

Quimrider · 03-02-2009, 02:06 PM

Thanks for the tip. I've tried messing with the choke and couldn't really tell a difference. When it gets warmer, I'll have to do a couple checks of the spark plug at freeway speed to see if I'm running rich or not. I suspect I may be a tad rich since there is more carbon build up on the exhaust that I would expect and the enricher aka "choke" seems not to make a difference.

Quimrider · 03-26-2009, 11:13 AM

I changed my needle shim a little. I have excessive carbon on the end of the exhaust which made me think it might be slightly rich. I moved the washer back to the stock position, went to lowes and bought some #4 stainless steel washers. They are almost exactly the same size as the carb's washer, but approx 1/2 as thick. I used one of these as a needle shim. It ran about the same. We'll see how it affects my mileage. Now on to my point... When I put things back together I forgot to tighten the boots between the airbox and engine. It ran fine at low speeds. I got on the freeway and it must have been sucking air around the boots. I could barely hit 60mph. I tried your choke trick and it sped up to 65-68ish. I guess with the boots tight my bike was already running rich enuff that the choke made no difference.

trykemike · 03-29-2009, 09:49 PM

Hey Quimrider. Thanks for the feed-back re: the "choke test" I was contemplating changing the main jet before I read your posts. I just took the bike out of storage. I set the fuel to prime for 5 secs then used normal starting procedures . The bike started right away and settled down to idle approx 1400-1500 rpm. I used the choke trick moving until rpm rose to 1750. The bike accelerated briskly ( easily left all cars way back off the line at the intersection. I went onto the main hwy ( our equivalent to the inter-state ) I took 3 rd to 65k 4 th to 90 k and 5 th went easily to 110 k . I kept rpm under 7000 about 6500. She is running perfectly. With fresh oil rapid shifting in either direction was smooth. Tried a speed shift @ 6500 all gears from a stop light after the hwy run. Not a "jet-bike" but quick enough. Now waiting for more warm days for the run to the lake and some lazy 80 k cruising in the country side.

MadCityRider · 06-11-2011, 06:19 PM

Anyone looking to switch to the 130 Main Jet (or wanting to swtich back) I've got some extras:

viewtopic.php?f=11&t=4616

:rawk:

geezer · 07-23-2011, 10:23 PM

well i decided to do what jaime did and move the needle over a ton. tomorow ill see what it does. ill be on a nice long ride with a chick on a suzuki 800cc. i still out ride her on the little gz! :rawk:

Water Warrior 2 · 07-24-2011, 04:09 AM

Quote:

Originally Posted by geezer

well i decided to do what jaime did and move the needle over a ton. tomorow ill see what it does. ill be on a nice long ride with a chick on a suzuki 800cc. i still out ride her on the little gz! :rawk:

Does that include very long hills with a headwind ?? Yeah, I had to say it. :lol: :lol: :lol: :lol:

geezer · 07-24-2011, 08:12 AM

HA! shes a beginner so around turns and stuff i can!

GinetteHuber · 03-15-2013, 09:25 PM

I will install the

main jet this weekend.

burkbuilds · 03-15-2013, 09:58 PM

Hey GinetteHuber,

Although this is a fairly old thread, I'm glad you resurrected it. The original poster's pictures and explanations of how to do this are the best I've seen, and I somehow missed this when it started and stayed active for a long time originally.

Good luck with your mod and let us know how it works.

03-02-2009, 12:32 PM	#31
trykemike Senior Member Join Date: May 2007 Location: toronto ont canada Posts: 177	Re: GZ250 power increase. Hey Quimrider re: the "choke" use your tach for this test. When the engine is warm and at idle with the choke off move the lever slightly until the rpm just starts to increase. Take a test ride it may/may not improve the performance. I have the spot marked so I use it on most cooler days and when I run on the freeway because acceleration improves on my bike. Try it. :??: __________________ sds4 Login or Register to Remove Ads
	0

03-02-2009, 02:06 PM	#32
Quimrider Senior Member Join Date: Jun 2007 Location: Toledo, OH Posts: 198	Re: GZ250 power increase. Thanks for the tip. I've tried messing with the choke and couldn't really tell a difference. When it gets warmer, I'll have to do a couple checks of the spark plug at freeway speed to see if I'm running rich or not. I suspect I may be a tad rich since there is more carbon build up on the exhaust that I would expect and the enricher aka "choke" seems not to make a difference.
	0

03-26-2009, 11:13 AM	#33
Quimrider Senior Member Join Date: Jun 2007 Location: Toledo, OH Posts: 198	Re: GZ250 power increase. I changed my needle shim a little. I have excessive carbon on the end of the exhaust which made me think it might be slightly rich. I moved the washer back to the stock position, went to lowes and bought some #4 stainless steel washers. They are almost exactly the same size as the carb's washer, but approx 1/2 as thick. I used one of these as a needle shim. It ran about the same. We'll see how it affects my mileage. Now on to my point... When I put things back together I forgot to tighten the boots between the airbox and engine. It ran fine at low speeds. I got on the freeway and it must have been sucking air around the boots. I could barely hit 60mph. I tried your choke trick and it sped up to 65-68ish. I guess with the boots tight my bike was already running rich enuff that the choke made no difference. Login or Register to Remove Ads
	0

03-29-2009, 09:49 PM	#34
trykemike Senior Member Join Date: May 2007 Location: toronto ont canada Posts: 177	Re: GZ250 power increase. Hey Quimrider. Thanks for the feed-back re: the "choke test" I was contemplating changing the main jet before I read your posts. I just took the bike out of storage. I set the fuel to prime for 5 secs then used normal starting procedures . The bike started right away and settled down to idle approx 1400-1500 rpm. I used the choke trick moving until rpm rose to 1750. The bike accelerated briskly ( easily left all cars way back off the line at the intersection. I went onto the main hwy ( our equivalent to the inter-state ) I took 3 rd to 65k 4 th to 90 k and 5 th went easily to 110 k . I kept rpm under 7000 about 6500. She is running perfectly. With fresh oil rapid shifting in either direction was smooth. Tried a speed shift @ 6500 all gears from a stop light after the hwy run. Not a "jet-bike" but quick enough. Now waiting for more warm days for the run to the lake and some lazy 80 k cruising in the country side. __________________ sds4
	0

06-11-2011, 06:19 PM	#35
MadCityRider Member Join Date: May 2011 Location: Madison Posts: 47	Re: GZ250 power increase. Anyone looking to switch to the 130 Main Jet (or wanting to swtich back) I've got some extras: viewtopic.php?f=11&t=4616 :rawk: __________________ :rawk: - MCR Login or Register to Remove Ads
	0

07-23-2011, 10:23 PM	#36
geezer Senior Member Join Date: Mar 2011 Location: dahlonega GA Posts: 563	Re: GZ250 power increase. well i decided to do what jaime did and move the needle over a ton. tomorow ill see what it does. ill be on a nice long ride with a chick on a suzuki 800cc. i still out ride her on the little gz! :rawk: __________________ 99 gz 250 and a currently dismantled fzr 1000
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07-24-2011, 08:12 AM	#38
geezer Senior Member Join Date: Mar 2011 Location: dahlonega GA Posts: 563	Re: GZ250 power increase. HA! shes a beginner so around turns and stuff i can! __________________ 99 gz 250 and a currently dismantled fzr 1000
	0

03-15-2013, 09:25 PM	#39
GinetteHuber Junior Member Join Date: Mar 2013 Location: 137 W San Bernardino Rd Posts: 4	Re: GZ250 power increase. I will install the main jet this weekend. __________________ It is easy for you to buy dvd online here and watch the seires with high quality DVD!
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03-15-2013, 09:58 PM	#40
burkbuilds Senior Member Join Date: Mar 2009 Location: Shannon, Georgia Posts: 1,268	Re: GZ250 power increase. Hey GinetteHuber, Although this is a fairly old thread, I'm glad you resurrected it. The original poster's pictures and explanations of how to do this are the best I've seen, and I somehow missed this when it started and stayed active for a long time originally. Good luck with your mod and let us know how it works.
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