Carb jet needles/ front vs rear

[Thunderbirds1]

Hey all,

It’s been years since my last post, but I am reviewing all posts regularly.

Recently I went through my carbs for some cleaning and other stuff. The bike is a 1993 1400, Vance and Hines pipes, K&N drop in filters, other than that the engine i stock. The bike runs pretty good, but just not as good as before.

Now I have a suspicion if I didn’t swap the front and rear jet needles, by accident. Does anyone have experience in that aspect? What would happen, are there tell tale symptoms? What are the size difference of the needles?

I thought I check here before I open them back up.

Thanks in advance.

Lee

[sgtcall]

Welcome back!
I don't have a answer for you but just in case here are a couple of things to check out.

INTRUDER MANUALS AND INFORMATION
viewtopic.php?f=19&t=14168

POSTING PICTURES ON INTRUDERS ALERT
viewtopic.php?f=19&t=13992

[Herb]

https://www.motosport.com/oem-parts/suz ... 28front%29

according to the parts fiche above, they are not the same part number. How much difference in performance it might make is anyone's guess.

[Thunderbirds1]

Thanks @sgtcall and @Herb for your input.

UPDATE: I just can’t stand having open questions, so I opened th carbs back up. Turns out there is a difference. It is so subtle, but for a carb probably huge.

Also, turns out I have a setup for the US model 1996 and later. Also jet sizes are for that setup. The bike is a 1993, and I’ve owned it since 2001. So the carbs have been rebuilt or replaced between 1992 and 2001, with parts for a later model. Now I will research if the carb bodies have changed after the 1996 changeover.

So, measurements and markings for the

front needle:

Marking 5D51
Overall length 52.52mm
E clip length 49.41mm

Rear needle
Marking 5D35
Overall length 52.38mm
E clip length 49.13mm

Diameter at tip 2.15mm same on both
Diameter at head 2.54mm same on both

So there is a difference, now I should find out if the 1995 and earlier model are how much difference.

More to follow. And thanks for all the input.

Lee

[hillsy v2]

While you are in there - check out the needle seats as well for signs of wear. The front carb on the VS lays relatively flat and the needle has more of a tendency the cut into the seat compared to the rear carb setup.

[Herb]

Thanks @sgtcall and @Herb for your input.

UPDATE: I just can’t stand having open questions, so I opened th carbs back up. Turns out there is a difference. It is so subtle, but for a carb probably huge.

Also, turns out I have a setup for the US model 1996 and later. Also jet sizes are for that setup. The bike is a 1993, and I’ve owned it since 2001. So the carbs have been rebuilt or replaced between 1992 and 2001, with parts for a later model. Now I will research if the carb bodies have changed after the 1996 changeover.

So, measurements and markings for the

front needle:

Marking 5D51
Overall length 52.52mm
E clip length 49.41mm

Rear needle
Marking 5D35
Overall length 52.38mm
E clip length 49.13mm

Diameter at tip 2.15mm same on both
Diameter at head 2.54mm same on both

So there is a difference, now I should find out if the 1995 and earlier model are how much difference.

More to follow. And thanks for all the input.

Lee

Yeah, there is a difference and you have them swapped. Since the rear does run richer than the front it could be causing a rich issue.

The following link takes you to the site where you can select the year and model. Then you can hunt up the part you want to find out about.

The OEM parts Fiche is a wealth of information.

https://www.motosport.com/oem-parts