Poor performance, bike will not go over ~40mph?

kinetic · 07-12-2012, 01:42 AM

Hey guys,

Great forum, been lurking for a while now.

I have 2 GZ's one runs GREAT, the other not so much. Lets chat about the latter.

The bike was purchased after being stored for a few years and had not been started. I loaded it up on the truck, brought it home and started to inspect everything. I pulled the carb off and gave it a cleaning per the service manual on this very site. I reinstalled the carb and boom it started right up and sounded great.

I finally got the chance to take this one out after a few other minor repairs ( sticky throttle ). The bike will just not go over 40mph for anything. I have checked the vacuum lines, they are all connected correctly. I have great fuel coming from the petcock and a brand new air filter. Compression is ~150psi. I cant figure out what the issue could be, everything looks and sounds great. I can flick the starter on this bike and it starts right up.

My only reference to performance is the other GZ which has exhaust, K&N, and a rejetted carb. So I know the stock one I am working on will not have the same power but this is abnormal performance at best.

Sorry for the longwinded post, any insight would be greatly appreciated!

-Marc

Thumperville · 07-12-2012, 01:55 AM

hopefully its something simple, maybe the brakes are ceased?

blaine · 07-12-2012, 01:57 AM

Welcome.It sounds like you still have a carb issue.A dirty M.J,the needle diaphram not sealing properly,or the float set too low.

:cool:

dentheman · 07-12-2012, 02:15 AM

I had that exact problem with my Shadow. Two of the four plugs were fouled. Once they were changed it runs great. Also, did you dump the old gas?

bonehead · 07-12-2012, 09:30 AM

I'd reinspect the carb and make sure it is working properly.

raul10141964 · 07-12-2012, 01:00 PM

It sounds like your carb do not open all the way

kinetic · 07-12-2012, 05:45 PM

Hey guys,

Thanks for all the replies. The butterfly opens all the way, I am going to pull it off again and make sure there is no blockage. I will report back, thanks again.

07-12-2012, 01:42 AM	#1
kinetic Junior Member Join Date: Jul 2012 Location: Orange County Posts: 2	Poor performance, bike will not go over ~40mph? Hey guys, Great forum, been lurking for a while now. I have 2 GZ's one runs GREAT, the other not so much. Lets chat about the latter. The bike was purchased after being stored for a few years and had not been started. I loaded it up on the truck, brought it home and started to inspect everything. I pulled the carb off and gave it a cleaning per the service manual on this very site. I reinstalled the carb and boom it started right up and sounded great. I finally got the chance to take this one out after a few other minor repairs ( sticky throttle ). The bike will just not go over 40mph for anything. I have checked the vacuum lines, they are all connected correctly. I have great fuel coming from the petcock and a brand new air filter. Compression is ~150psi. I cant figure out what the issue could be, everything looks and sounds great. I can flick the starter on this bike and it starts right up. My only reference to performance is the other GZ which has exhaust, K&N, and a rejetted carb. So I know the stock one I am working on will not have the same power but this is abnormal performance at best. Sorry for the longwinded post, any insight would be greatly appreciated! -Marc Login or Register to Remove Ads
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07-12-2012, 01:55 AM	#2
Thumperville Junior Member Join Date: Jun 2012 Location: mid west Posts: 15	Re: Poor performance, bike will not go over ~40mph? hopefully its something simple, maybe the brakes are ceased?
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07-12-2012, 01:57 AM	#3
blaine Senior Member Join Date: Feb 2010 Location: P.E.I. Canada Posts: 3,784	Re: Poor performance, bike will not go over ~40mph? Welcome.It sounds like you still have a carb issue.A dirty M.J,the needle diaphram not sealing properly,or the float set too low. :cool: __________________ If at first you do succeed, try not to look surprised. Login or Register to Remove Ads
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07-12-2012, 02:15 AM	#4
dentheman Senior Member Join Date: Apr 2010 Location: Lubbock, TX Posts: 629	Re: Poor performance, bike will not go over ~40mph? I had that exact problem with my Shadow. Two of the four plugs were fouled. Once they were changed it runs great. Also, did you dump the old gas? __________________ 2007 Shadow Spirit 750
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07-12-2012, 09:30 AM	#5
bonehead Senior Member Join Date: May 2009 Location: elgin,tx Posts: 907	Re: Poor performance, bike will not go over ~40mph? I'd reinspect the carb and make sure it is working properly. __________________ Standing with the PGR until they stand for me. Login or Register to Remove Ads
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07-12-2012, 01:00 PM	#6
raul10141964 Senior Member Join Date: Apr 2012 Location: Elkhart, Indiana Posts: 369	Re: Poor performance, bike will not go over ~40mph? It sounds like your carb do not open all the way
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07-12-2012, 05:45 PM	#7
kinetic Junior Member Join Date: Jul 2012 Location: Orange County Posts: 2	Re: Poor performance, bike will not go over ~40mph? Hey guys, Thanks for all the replies. The butterfly opens all the way, I am going to pull it off again and make sure there is no blockage. I will report back, thanks again.
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