Irregular engine at low speeds

Jam24 · Yesterday, 12:40 AM

I recently noticed irregular RPM on my bike at low speeds and when idling. It seems to have gaps in its rhythm. At higher speeds, everything seems to work fine. I haven’t noticed any other strange sounds (clanking or knocking or anything like that). Does that sound like spark plugs or a carburetor problem? Any suggestions about what might be wrong or how to accurately diagnose the problem would be greatly appreciated! Thanks!

Vegas Street Rider · Yesterday, 01:57 AM

You might have a petcock diaphragm with a hole in it or the vacuum hose from the petcock to the carb going bad or loose. Fuel flow depends on good vacuum. Best I can come up with. Good luck.

alantf · Yesterday, 04:31 AM

Don't forget that idle revs should be set at 1200-1400 revs. Not 800 like a car.

Jam24 · Yesterday, 12:30 PM

I think this might be it. The bike came with an aftermarket replacement peacock that definitely isn

Jam24 · Yesterday, 12:33 PM

Quote:

Originally Posted by Vegas Street Rider

You might have a petcock diaphragm with a hole in it or the vacuum hose from the petcock to the carb going bad or loose. Fuel flow depends on good vacuum. Best I can come up with. Good luck.

I think this might be it. The bike came with an aftermarket replacement peacock that definitely isn

Vegas Street Rider · Yesterday, 06:09 PM

You might check a site called Partzilla if you need to replace it with an OEM fuel petcock. They have quite and inventory for the GZ 250. If you have problems finding one, let me know as I have a rebuilt one that I might be willing to part with for a fair price.

Yesterday, 12:40 AM	#1
Jam24 Junior Member Join Date: Mar 2024 Posts: 4	Irregular engine at low speeds I recently noticed irregular RPM on my bike at low speeds and when idling. It seems to have gaps in its rhythm. At higher speeds, everything seems to work fine. I haven’t noticed any other strange sounds (clanking or knocking or anything like that). Does that sound like spark plugs or a carburetor problem? Any suggestions about what might be wrong or how to accurately diagnose the problem would be greatly appreciated! Thanks! Login or Register to Remove Ads Last edited by Jam24; Yesterday at 12:42 AM.
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Yesterday, 04:31 AM	#3
alantf Senior Member Join Date: Nov 2008 Location: Tenerife (Spain) Posts: 3,720	Don't forget that idle revs should be set at 1200-1400 revs. Not 800 like a car. __________________ By birth an Englishman, by the grace of God a Yorkshireman. Login or Register to Remove Ads
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Yesterday, 12:30 PM	#4
Jam24 Junior Member Join Date: Mar 2024 Posts: 4	I think this might be it. The bike came with an aftermarket replacement peacock that definitely isn Last edited by Jam24; Yesterday at 12:33 PM.
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Yesterday, 01:57 AM	#2
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,110	You might have a petcock diaphragm with a hole in it or the vacuum hose from the petcock to the carb going bad or loose. Fuel flow depends on good vacuum. Best I can come up with. Good luck.
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Yesterday, 06:09 PM	#6
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,110	You might check a site called Partzilla if you need to replace it with an OEM fuel petcock. They have quite and inventory for the GZ 250. If you have problems finding one, let me know as I have a rebuilt one that I might be willing to part with for a fair price.
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