Jetting FYI on a 1980 GS1000E

[dorkburger]

Old thread. Could have been handy but didn't stay current.

https://www.thegsresources.com/_forum/showthread.php?225932-Carb-Jetting-List&highlight=

[salty_monk]

These aren't my carbs (think these are off an XS650 but it's the same carb) but you can see the air corrector jets here.. the bigger one on the left can be unscrewed and changed out, the smaller one on the right is fixed & the Dynajet kit for the 1980 GS1000 comes with a small brass bush that pushes in there & restricts the airflow...

[winmag4582001]

You can change the sprocket ratios to ANYTHING you want, it won't affect the speedo reading.

Your speedometer gets information from the front tire. Only three things might affect accuracy. 1. Improper size tire. Your best results will be with a 100/90-19. 2. Improper drive gear at the axle. Most GSes have a 19" front tire, and will have the same ratio. A few models had an 18" tire, a couple more models had a 16" tire. Use of any of those would slow down the speedo, not make it read faster. 3. The speedo unit itself. If it's a stock unit, it should not be a problem. However, if an aftermarket unit has been installed, there is no telling whether a correct ratio unit was installed. A speedo should not bounce. Try lubing the cable. If that does not help the bounce, you might have to open up the speedo so you can clean and lube it.

.

Again, a mistake on my part. In the rush to get it done, I only screwed it on the back of the speedo about 1 thread.

[winmag4582001]

I

These aren't my carbs (think these are off an XS650 but it's the same carb) but you can see the air corrector jets here.. the bigger one on the left can be unscrewed and changed out, the smaller one on the right is fixed & the Dynajet kit for the 1980 GS1000 comes with a small brass bush that pushes in there & restricts the airflow...

Ok, so they are blocking the lower right port. I may give that a quick try and see what it does. I installed new factory size little jets.

[winmag4582001]

Old thread. Could have been handy but didn't stay current.
https://www.thegsresources.com/_foru...ist&highlight=

Agreed. I didn’t see that thread on a search. I’ll add to it when I’m done tuning. TY

[winmag4582001]

So I blocked off the right side air jets(4mm hole) of the air intake side of the carbs and the midrange was better, so this morning I ordered 4 main air jet correctors from Dynojet (part# DC0301). They were only $2 each. I'll update when I install them to see if my saga is finally over. I'm starting to think CV carbs SUCK.

[steve murdoch]

Thank you for continuing to post your results in your search for the spot-on jetting.
Have a look at this article from Mike Nixon on CV carbs at altitude. He is a carb guru on a number of Honda sites.

https://www.motorcycleproject.com/text/carbs_altitude.html

[winmag4582001]

****FINALLY!!!!!****

155/152.5 main jets
Needles are up 1.5mm (two small washers on top of needle)
Idle fuel screws out 2 1/2 turns +/-
K&N pods
V&H 4into1
Float height factory
Valves are set at the high end of tolerance
Used DynoJet 4mm air jet plug (right side air port opposite of the jet on air intake side) Part #DC0301 $2 each

Installing the Dynojet plugs made a huge difference

[Nessism]

Are you using DJ jets? Reason for asking is because the numbering scheme is different from Mikuni.

[salty_monk]

****FINALLY!!!!!****

Used DynoJet 4mm air jet plug (right side air port opposite of the jet on air intake side) Part #DC0301 $2 each

Installing the Dynojet plugs made a huge difference

Woohoo, I'm glad I came across this thread then!

[winmag4582001]

Are you using DJ jets? Reason for asking is because the numbering scheme is different from Mikuni.

NO. I should have mentioned that. I got the main jets from 6sigma.
I've gotten other jets from JetsRus, it said they were for Mikuni carbs so I assume they are in line with Mikuni's numbering system...

[winmag4582001]

Woohoo, I'm glad I came across this thread then!

Also, I have went down to 1 shim on top of the needle e-clip. Basically up 2mm now on the needles. Running and pulling hard.

[winmag4582001]

OK. So the GS1000E is running 99.9%.
The last thing I'm looking for now are needles...... factory needles are as follows:
Length: 51.5mm
D1: 3mm
D2: 3mm
D3: 2.8mm
D4: 2.6mm
D5: 2.5mm

Wanting a little thinner needle, maybe something that starts at 3mm and tapers to 2.2mm. I've been combing the net and not finding any real numbers I can go off of and I dont have a lathe that can turn something that small. What have any of you used?
TIA

[GregT]

OK. So the GS1000E is running 99.9%.
The last thing I'm looking for now are needles...... factory needles are as follows:
Length: 51.5mm
D1: 3mm
D2: 3mm
D3: 2.8mm
D4: 2.6mm
D5: 2.5mm

Wanting a little thinner needle, maybe something that starts at 3mm and tapers to 2.2mm. I've been combing the net and not finding any real numbers I can go off of and I dont have a lathe that can turn something that small. What have any of you used?
TIA

If you're looking to richen the midrange - thinner needles - you can get the same effect by using smaller air correctors.
You say you're using 4mm air correctors, I'd go a little smaller and try it.

[Grimly]

Wanting a little thinner needle, maybe something that starts at 3mm and tapers to 2.2mm. I've been combing the net and not finding any real numbers I can go off of and I dont have a lathe that can turn something that small. What have any of you used?
TIA

I suggest you look up manual thinning of SU needles, using a pillar drill.