1980 Suzuki GS1000E - Help Determining Needle Jet Size

[Guest]

1980 GS1000E / Mikuni BS34 Carbs


4to1
K&N Pods
45 Pilot / 1.5 turns out
137.5 Main


In the process of fine tuning my carbs (BS34SS). At 4 notches down on the needles (half way down), 1/4-1/2 throttle is lean bogging. Only way I can remove the hesitation/bog is by richening the needles all the way + a washer, but then my 3/4-full is too rich and won't pull through redline. I ordered some smaller mains to see if I can get her to appreciate full throttle, but I'm worried about 1/8-1/2 being too rich because of the needle height.


I've tried resolving the issue with a DynoJet kit. No luck. Same hesitation if I don't raise the jet needles. Only way to resolve it with the kit is to richen them all the way +2 washers, but then the bike is a rich slug from 1/8-full.


It seems I'd do well to raise my needle jets 1 size. Stock in these carbs are Suzuki "318 X-7" needle jets--~41mm overall height. Can't tell exactly the inner diameter, but it seems to be about 2.68mm. When looking at the charts I found, it looks like the Mikuni 176/270 P-7 needle jets are a match, but I'm not positive.


Anybody know what the Suzuki 318 X-7 needle jets translate to in Mikuni's world or how to figure it out? Looks like the 176 series to me, but I want to be sure before I throw green paper at anything...


Here's some links for research's sake if anyone wants to play sleuth with me:

[1980GS1000E]

CV carbs are never going to operate properly with pods.

[GSX1000E]

Too rich on the pilots and mains. I am surprised that it runs. Do you have some kind of air injection pump system hooked up?

[Phaedrus]

Too rich on the pilots and mains. I am surprised that it runs. Do you have some kind of air injection pump system hooked up?

Gonna drop back down to 42.5 pilots. Couldn't get her to hold idle with stock 40s.

What sized mains do you recommend? She seems to like 137.5s with the needles @ 4 notches. Was gonna try 132s with the needles all the way up.

[GSX1000E]

Those carbs need to be thoroughly cleaned to begin with. If the muffler has any packing at all in it, 40 pilot jets, raise the stock needle with ONE 3mm flat washer and install 127.5 or 130 main jets.
ONLY, AFTER you THOROUGHLY clean those carbs. You can choose to find problems that don't exist if you wish. I prefer to ride them myself. CLEAN THOSE CARBS. (<did I forget that part?)

[Phaedrus]

Those carbs need to be thoroughly cleaned to begin with. If the muffler has any packing at all in it, 40 pilot jets, raise the stock needle with ONE 3mm flat washer and install 127.5 or 130 main jets.
ONLY, AFTER you THOROUGHLY clean those carbs. You can choose to find problems that don't exist if you wish. I prefer to ride them myself. CLEAN THOSE CARBS. (<did I forget that part?)

I'll give it a shot. The muffler is part of the old ProSport 4to1, no baffling at all. Upgraded from **** emgo pods to K&Ns when I was building the bike, idle went bye-bye--too much air. After another thorough clean, I'll try the 40 pilots again, see if they'll take.

Now, this is something I've been confused about since I picked up this bike. Never worked with CV carbs before, but the needles that were in my set look like this:



Except, mine are even more tapered. So pointy, they almost look like toothpicks... The PO had obviously been in the carbs before, but it wasn't clear to me what had been changed. I cleaned and rebuilt them, but left the needles not knowing any better.

After so many hours trying to get this bike to run right, it became apparent that I might have the wrong needles and that these 5D50s are what should be in there:



The 5D50s look a hell of a lot more like the DynoJet needles that came with my kit too...

You told me to raise the needle using 1 washer, which again raised a flag--my needle has clip positions. Am I right to conclude that I've been running the wrong stock needle this whole time?...

[GSX1000E]

By running it ONE washer higher, I meant to replace the factory plastic spacer with (4) 3mm flat washers which effectively raises the stock jet needle ONE washer or .048-.052mm
Sorry for the confusion.

[Phaedrus]

By running it ONE washer higher, I meant to replace the factory plastic spacer with (4) 3mm flat washers which effectively raises the stock jet needle ONE washer or .048-.052mm
Sorry for the confusion.

Got it. Still, which needle of those pictured is the one that I should have in my BS34 carbs?

[GSX1000E]

I would start with the factory needle as that is what I was working around with my suggestions. With the various different needles that you currently have on hand,
I would think that you have plenty of fine tuning options besides those.
I have a Dynajet replacement kit that I bought years ago (practically free) to compare what they suggest with what works for me and have yet to have the desire to do a thorough investigation.
Some day I will get out the micrometer and compare the parts myself. I just have no immediate need to do so.

[rapidray]

CV carbs are never going to operate properly with pods.

This is flat out a LIE!!! Please have experience before you spout off stuff you don't know about.
Ray.

[chef1366]

Use stock 45 pilot jets, three up on the DJ needle, (stock exhaust?) 132 DJ main.
Take the idle mixture screws out 3.5 turns out.
If the carbs are dirty none of this will work.

[GSX1000E]

You DO realize that he has a 2-valve 1000 engine that came with 40 pilot jets, right?

[chef1366]

You DO realize that he has a 2-valve 1000 engine that came with 40 pilot jets, right?

Wow
Sorry but saw 1100e

[ozman]

This is flat out a LIE!!! Please have experience before you spout off stuff you don't know about.
Ray.

ray is correct its just more of a pain getting CV carbs setup but it can be done

[GSX1000E]

The only ones that say it cannot be done without a kit are typically those that have difficulty making a stock bike run.
Remember that often times free advice on the internet is worth exactly what it costs and usually comes from those with NO first hand experience.
"Chose wisely grasshopper".