My GZ 's top speed seems low - Page 2

paulisnofun · 08-23-2012, 12:08 AM

I don't have a history on the bike, but incan ask the guy I bought it from a few questions.
I took the filter out, and banged it around a bit and shook out any debris that was in there. I am going to pick up some some seafoam and dump it on the gas tank. I am also going to try to research a little more about vacuum leaks, and how to find them.

**jonathan180iq** · 08-23-2012, 09:33 AM

There are only a couple of hoses on the bike.
Someone correct me if I am wrong, cause I'm just going by memory.

There should be 2 lines running between the gas tank and the carb. And 1 or 2 between the crankcase and the air box.
That's it, unless I missed one. So you basically just check that those hoses are connected and snug and that the rubber isn't degrading.

That being said, if you aren't getting any rev lag, popping on deceleration or crazy bucking while trying to accelerate, then you are most likely ok. It's good to give them a once over every now and then though.

Try the seafoam. These carbs can be persnickettey with even the tiniest amount of debris in there.
Also, slosh the gas tank around a bit. I know this sounds ridiculous, but those petcock screens can develop a varnish that will impede gas flow.

Lots of little things to try.

paulisnofun · 08-23-2012, 09:47 AM

Last night when I started the bike, it would run for a second, then stall. I think the rpms were a little too low. I turned...ummm...screw thing that changes the idle speed and increased the idle a bit. I don't have a tach so I was kind of listening to how mine sounded against what other GZs sounded like on Youtube. After increasing the idle, the revs were hanging up for longer than they were when the idle was set lower, and I have been hearing popping.
I will check the hoses and see how they look. I watched a few videos, and read a few posts, that said to spray WD-40 on the carb and the connections and to listen to the rpms to help find the leak. Is this good advice, or is the internet lying?

fatoldfool · 08-23-2012, 10:04 PM

If there is a vacuum leak the engine will rev up a bit when the WD40 is sprayed there. It gives the engine more fuel.
My GZ runs great, no missing or popping but it will only run 65 on level and drops to 60 or 55 quickly on a grade.

Be sure and check that tire pressure, and with your weight, I would run about 2 psi above the recommended pressure on the front

Good luck!

paulisnofun · 08-24-2012, 05:10 PM

I checked for vacuum leaks. It looks like all of the hoses and clamps are new. I sprayed WD-40 on the hoses and boots and the rpms did not change. I poured some seafoam in the fuel tank and took it for a quick ride (have not checked tire pressure yet), but didn't get it over 35 mph due to speed limits (25) in my borough.
I wasn't able to find any vacuum leaks, but I recorded two short videos of my bike idling, with a few revs. I hear some popping, but you guys probably have better mechanical hearing than I do. Can you give me your opinion on if you hear any rev lag and/ or popping when the rpms decelerate?
Also, does it sound like my idle rpm is high, low, or about right?

Video 1
[youtube]http://www.youtube.com/watch?v=Rg7i5ug4epY&feature=context-cha[/youtube]

Video 2
[youtube]http://www.youtube.com/watch?v=PRrEZyCVPNk&feature=context-cha[/youtube]

Thanks again for your help everyone. I really do appreciate it.

Sorry...couldn't get the videos to embed.

vikz250 · 08-24-2012, 07:18 PM

Mine can go 40 to 45 mph on 3rd gear and can easily hit 50 to 60 mph in 4th but I have only done it once on a highway but typically I stay on 3rd most way and have no problem hoing 40mph..

raul10141964 · 08-28-2012, 12:26 PM

open the choke a little if the power increase install a bigger main jet

Kcarvajal · 08-29-2012, 12:14 AM

One suggestion... Check your throttle cable to make sure it's not too loose to the point where it isn't opening the carb enough. Another thing is your clutch cable. Make sure you have enough slack. You can adjust his from the lever. Make sure the lever has a gap about the space of a dime.

I had a similar experience before a long ride and thought I'd have to back out. Come to realize I tightened the cable too much and wasn't getting all of my clutch.

Try those out and let us know.

Ken

b1pig · 08-29-2012, 02:45 PM

Paul,

my wife's GZ goes much faster than 50. medium saddle bags, a small windscreen and my 5-10, 215lb self can see 70+ on flat ground. fastest i've riden her bike was an indicated 75-ish. her carb gummed up the first winter we had it. i removed it and cleaned it, but it still had idle issues with some loss of power. i adjusted the pilot screw and its a whole different animal now along with the new front sprocket.

you should read this thread:
viewtopic.php?f=8&t=617

my thread where i had a similar issue
viewtopic.php?t=3888

paulisnofun · 08-29-2012, 04:21 PM

Thanks for the advice Kcarvajal and B1pig. I will take a look at the throttle and clutch cable, and make sure they are just right. I dumped some carb cleaner in the engine hoping to clean the carb up a bit. Since I am not mechanical in any way, I probably shouldn't take the carb off and clean it.
One other question. When I ride to work and I am going around 45 or 50 and need to stop at a traffic light, when I stop the bike the revs seem really high. I mean really high. I don't have a tac, but it sounds like the engine is still running does when riding at a higher speed. That's not good, right? What could be causing that?

08-23-2012, 12:08 AM	#11
paulisnofun Junior Member Join Date: Aug 2012 Location: South Eastern Pennsylvania Posts: 13	Re: My GZ 's top speed seems low I don't have a history on the bike, but incan ask the guy I bought it from a few questions. I took the filter out, and banged it around a bit and shook out any debris that was in there. I am going to pick up some some seafoam and dump it on the gas tank. I am also going to try to research a little more about vacuum leaks, and how to find them. Login or Register to Remove Ads
	0

08-23-2012, 09:33 AM	#12
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	Re: My GZ 's top speed seems low There are only a couple of hoses on the bike. Someone correct me if I am wrong, cause I'm just going by memory. There should be 2 lines running between the gas tank and the carb. And 1 or 2 between the crankcase and the air box. That's it, unless I missed one. So you basically just check that those hoses are connected and snug and that the rubber isn't degrading. That being said, if you aren't getting any rev lag, popping on deceleration or crazy bucking while trying to accelerate, then you are most likely ok. It's good to give them a once over every now and then though. Try the seafoam. These carbs can be persnickettey with even the tiniest amount of debris in there. Also, slosh the gas tank around a bit. I know this sounds ridiculous, but those petcock screens can develop a varnish that will impede gas flow. Lots of little things to try.
	0

08-23-2012, 09:47 AM	#13
paulisnofun Junior Member Join Date: Aug 2012 Location: South Eastern Pennsylvania Posts: 13	Re: My GZ 's top speed seems low Last night when I started the bike, it would run for a second, then stall. I think the rpms were a little too low. I turned...ummm...screw thing that changes the idle speed and increased the idle a bit. I don't have a tach so I was kind of listening to how mine sounded against what other GZs sounded like on Youtube. After increasing the idle, the revs were hanging up for longer than they were when the idle was set lower, and I have been hearing popping. I will check the hoses and see how they look. I watched a few videos, and read a few posts, that said to spray WD-40 on the carb and the connections and to listen to the rpms to help find the leak. Is this good advice, or is the internet lying? Login or Register to Remove Ads
	0

08-23-2012, 10:04 PM	#14
fatoldfool Member Join Date: May 2012 Location: southern WV Posts: 55	Re: My GZ 's top speed seems low If there is a vacuum leak the engine will rev up a bit when the WD40 is sprayed there. It gives the engine more fuel. My GZ runs great, no missing or popping but it will only run 65 on level and drops to 60 or 55 quickly on a grade. Be sure and check that tire pressure, and with your weight, I would run about 2 psi above the recommended pressure on the front Good luck!
	0

08-24-2012, 05:10 PM	#15
paulisnofun Junior Member Join Date: Aug 2012 Location: South Eastern Pennsylvania Posts: 13	Re: My GZ 's top speed seems low I checked for vacuum leaks. It looks like all of the hoses and clamps are new. I sprayed WD-40 on the hoses and boots and the rpms did not change. I poured some seafoam in the fuel tank and took it for a quick ride (have not checked tire pressure yet), but didn't get it over 35 mph due to speed limits (25) in my borough. I wasn't able to find any vacuum leaks, but I recorded two short videos of my bike idling, with a few revs. I hear some popping, but you guys probably have better mechanical hearing than I do. Can you give me your opinion on if you hear any rev lag and/ or popping when the rpms decelerate? Also, does it sound like my idle rpm is high, low, or about right? Video 1 [youtube]http://www.youtube.com/watch?v=Rg7i5ug4epY&feature=context-cha[/youtube] Video 2 [youtube]http://www.youtube.com/watch?v=PRrEZyCVPNk&feature=context-cha[/youtube] Thanks again for your help everyone. I really do appreciate it. Sorry...couldn't get the videos to embed. Login or Register to Remove Ads
	0

08-24-2012, 07:18 PM	#16
vikz250 Member Join Date: Feb 2012 Location: wenatchee Posts: 98	Re: My GZ 's top speed seems low Mine can go 40 to 45 mph on 3rd gear and can easily hit 50 to 60 mph in 4th but I have only done it once on a highway but typically I stay on 3rd most way and have no problem hoing 40mph..
	0

08-28-2012, 12:26 PM	#17
raul10141964 Senior Member Join Date: Apr 2012 Location: Elkhart, Indiana Posts: 369	Re: My GZ 's top speed seems low open the choke a little if the power increase install a bigger main jet
	0

08-29-2012, 12:14 AM	#18
Kcarvajal Member Join Date: May 2011 Posts: 61	My GZ 's top speed seems low One suggestion... Check your throttle cable to make sure it's not too loose to the point where it isn't opening the carb enough. Another thing is your clutch cable. Make sure you have enough slack. You can adjust his from the lever. Make sure the lever has a gap about the space of a dime. I had a similar experience before a long ride and thought I'd have to back out. Come to realize I tightened the cable too much and wasn't getting all of my clutch. Try those out and let us know. Ken
	0

08-29-2012, 02:45 PM	#19
b1pig Senior Member Join Date: Mar 2010 Location: ray city, ga Posts: 121	Re: My GZ 's top speed seems low Paul, my wife's GZ goes much faster than 50. medium saddle bags, a small windscreen and my 5-10, 215lb self can see 70+ on flat ground. fastest i've riden her bike was an indicated 75-ish. her carb gummed up the first winter we had it. i removed it and cleaned it, but it still had idle issues with some loss of power. i adjusted the pilot screw and its a whole different animal now along with the new front sprocket. you should read this thread: viewtopic.php?f=8&t=617 my thread where i had a similar issue viewtopic.php?t=3888
	0

08-29-2012, 04:21 PM	#20
paulisnofun Junior Member Join Date: Aug 2012 Location: South Eastern Pennsylvania Posts: 13	Re: My GZ 's top speed seems low Thanks for the advice Kcarvajal and B1pig. I will take a look at the throttle and clutch cable, and make sure they are just right. I dumped some carb cleaner in the engine hoping to clean the carb up a bit. Since I am not mechanical in any way, I probably shouldn't take the carb off and clean it. One other question. When I ride to work and I am going around 45 or 50 and need to stop at a traffic light, when I stop the bike the revs seem really high. I mean really high. I don't have a tac, but it sounds like the engine is still running does when riding at a higher speed. That's not good, right? What could be causing that?
	0