CIS K-Jet Air/Fuel hex tool
#1
Drifting
Thread Starter
CIS K-Jet Air/Fuel hex tool
My understanding is that the k-jet Air/fuel mixture adjustment for my ‘78 requires a longer-than-normal hex wrench. What’s the minimum acceptable length for the tool to work without removing the air box? 9”? 12”?
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Thanks all.
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Thanks all.
#2
Pro
Here's one that is 6", but I seem to remember seeing one that looked longer than normal in the manuals.
https://www.aasesales.com/products/da2l-i61-4i-113880
Looking in the K-Jet workshop manual, it has the part number for the 911/924, but the 928 is just specified as "manufacturer tool", which is oh so helpful.
It does state that it should be a ball-end wrench, though.
K-Jet CO2 calibration snip
https://www.aasesales.com/products/da2l-i61-4i-113880
Looking in the K-Jet workshop manual, it has the part number for the 911/924, but the 928 is just specified as "manufacturer tool", which is oh so helpful.
It does state that it should be a ball-end wrench, though.
K-Jet CO2 calibration snip
#3
Drifting
Thread Starter
Yeah MrMerlin and I were chatting at the Rendezvous 928 event and he mentioned that the regular 6” version won’t work unless you modify the handle to make it longer. I found a 9” version on amazon with a ball end for <$10 so I’ll try that.
#4
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
The one I have has a screwdriver handle rather than the T, and a flex section just above the hex. Had it since the late 1970's so can't point to a source. It does not have a ball end.
Reminder that you MUST remove the tool after adjusting, before you ref the engine. Else the tool or the arm will get bent.
Reminder that you MUST remove the tool after adjusting, before you ref the engine. Else the tool or the arm will get bent.
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#6
RL Community Team
Rennlist Member
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If the airbox is out of the way, any 3mm hex will work. My setup is non-standard so I don't know how long an adjusting wrench you'd need leaving the stock airbox in place, but the info provided by others below should provide that.
To understand how it works, this assembly has a 3mm hex in the top. When you put your wrench into it and push down to compress the spring, the other end under the plate actually mates with the real 3mm hex mixture adjustment screw, where turning the top section then turns the mixture screw. The spring puts upward pressure on the o-ring at the base when your not adjusting to seal the adjusting mechanism to the shoe so you don't have a vacuum leak. The bottom of the extension piece often gets worn and then doesn't engage well with the mixture screw. In that case you might need to remove the assembly and grind off a little of the bottom piece to get a clean engagement again.
To understand how it works, this assembly has a 3mm hex in the top. When you put your wrench into it and push down to compress the spring, the other end under the plate actually mates with the real 3mm hex mixture adjustment screw, where turning the top section then turns the mixture screw. The spring puts upward pressure on the o-ring at the base when your not adjusting to seal the adjusting mechanism to the shoe so you don't have a vacuum leak. The bottom of the extension piece often gets worn and then doesn't engage well with the mixture screw. In that case you might need to remove the assembly and grind off a little of the bottom piece to get a clean engagement again.
#7
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My understanding is that the k-jet Air/fuel mixture adjustment for my ‘78 requires a longer-than-normal hex wrench. What’s the minimum acceptable length for the tool to work without removing the air box? 9”? 12”?
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Thanks all.
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Thanks all.
Air/Fuel Adjustment Tool for the Porsche® 928
Application: Porsche® 928 78-84 K-Jetronic (CIS) and L-JetronicThis is the perfect tool to adjust the air/fuel ratio (also referred to as CO in the manual) on the 928. For both K-Jetronic and L-Jetronic equipped cars.
ItemPart NumberPrice(USD)Shipping*Availability
Standard Air/Fuel Adjustment Tool for the Porsche® 928TOL-AFAT$14.20U.S. Only: $8.00
All Others:
Ships in 1 Week or Less
* Domestic US shipping shown. International shipping will be calculated based on location.
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