Pilot air jet confusion

Tarzan · 08-10-2014, 05:53 PM

I completely disassembled, cleaned and reassembled my carb and have flat acceleration. I am thinking I may have switch the two jets.
1 is in the inlet side of the throat of the carb. 2 is inside under the diaphragm on the side. Can anyone tell me the size of each jet? Or at least tell me which one is larger than the other?

I will try and post a pic of what I am talking about.

**jonathan180iq** · 08-11-2014, 08:46 AM

your images are blocked via my work server. I should be able to recognize what's what once I get to a different computer.

Don't let me forget.

**jonathan180iq** · 08-15-2014, 09:55 AM

Sorry for the delay - props to 5thBike for getting my ass in gear...

#1 is a front main fuel jet, its an 87.5 from the factory.

#2 is a pilot air jet, it's a 120 from the factory.

They should be slightly different in pitch, but they would fit into each other's slot, so it's possible that you mixed them up. If they are factory parts, you can look on the end of each of them and see their number stamp.

Describe your flat spot in acceleration. It's also easy to pinch the rubber diaphragm on top of the carb and that would cause some a pretty big flat in the mid range.

Tarzan · 08-18-2014, 08:53 PM

Thank you for the information. I pulled the carb and the jets were in the right places. So I will pull the top and check the diaphragm. That thing is a pain to get to stay. It seems to have shrunk a little while apart.

**jonathan180iq** · 08-19-2014, 08:31 AM

You can wet it with a little gas or use some kerosene. The moisture will let you play with it a little more during the install without the risk of tearing it. A hole of any kind means you have to replace it.

08-15-2014, 09:55 AM	#3
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	Sorry for the delay - props to 5thBike for getting my ass in gear... #1 is a front main fuel jet, its an 87.5 from the factory. #2 is a pilot air jet, it's a 120 from the factory. They should be slightly different in pitch, but they would fit into each other's slot, so it's possible that you mixed them up. If they are factory parts, you can look on the end of each of them and see their number stamp. Describe your flat spot in acceleration. It's also easy to pinch the rubber diaphragm on top of the carb and that would cause some a pretty big flat in the mid range. Login or Register to Remove Ads
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08-19-2014, 08:31 AM	#5
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	You can wet it with a little gas or use some kerosene. The moisture will let you play with it a little more during the install without the risk of tearing it. A hole of any kind means you have to replace it. Login or Register to Remove Ads
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08-10-2014, 05:53 PM	#1
Tarzan Junior Member Join Date: Apr 2014 Location: Chandler,Az. Posts: 5	Pilot air jet confusion I completely disassembled, cleaned and reassembled my carb and have flat acceleration. I am thinking I may have switch the two jets. 1 is in the inlet side of the throat of the carb. 2 is inside under the diaphragm on the side. Can anyone tell me the size of each jet? Or at least tell me which one is larger than the other? I will try and post a pic of what I am talking about. Login or Register to Remove Ads Last edited by Tarzan; 08-10-2014 at 05:58 PM.
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08-11-2014, 08:46 AM	#2
jonathan180iq Super Moderator Join Date: Jan 2007 Location: Dalton, GA Posts: 3,996	your images are blocked via my work server. I should be able to recognize what's what once I get to a different computer. Don't let me forget.
	0

08-18-2014, 08:53 PM	#4
Tarzan Junior Member Join Date: Apr 2014 Location: Chandler,Az. Posts: 5	Thank you for the information. I pulled the carb and the jets were in the right places. So I will pull the top and check the diaphragm. That thing is a pain to get to stay. It seems to have shrunk a little while apart.
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