1978 GS1000E carb needle position question

[slip]

My bike was really running like crap in the mid range of throttle. So I decided to take the carbs off and clean them. Bought the Berrymans dip. Wow, the carbs are filthy. I have a 4 into 1 supertrapp pipe, and K&N pods on the bike. I see that the PO did go up 4 sizes with the main jet to 112.5. The needle clips were at the middle position. Is this right for this setup??? Cause it was really bogging down in the midrange, but I guess it could be the dirty carbs, or dirty Pods. I am going to get the K&N cleaner and oil to go over these as well. I'll also check the float height while I am at it.

 

[Steve]

Keep in mind that I am not a VM carb expert (and it's been several months since I stayed at a Holiday Inn Express), but I would have guessed that four sizes is not quite enough for pods and a pipe. Have you done any plug chops to check the jetting? That is the only way to tell for sure, but I would guess another two sizes on the main jets and lower the clip to raise the needle at least one notch.

.

 

[Big T]

I'd start by getting them clean, putting in new O rings for the carbs and cylinder head and putting it back together, running it a bit and seeing what your plugs look like then.

No sense in changing things until you have a baseline to work from.

You're already up 6 sizes from the stock 95 mains.

But, the pilot jets and needle are typically more important as most 1000s don't spend much time over 5,000 rpm.

What size are the pilots?

 

[slip]

I'd start by getting them clean, putting in new O rings for the carbs and cylinder head and putting it back together, running it a bit and seeing what your plugs look like then.

No sense in changing things until you have a baseline to work from.

You're already up 6 sizes from the stock 95 mains.

But, the pilot jets and needle are typically more important as most 1000s don't spend much time over 5,000 rpm.

What size are the pilots?

Pilot jet size is 25. Should I leave the clip in the middle slot of needle jet???

 

[Big T]

For now, leave it there

Finish your carb cleaning and do some plug chops and see what your plugs look like. Then make changes as needed.

 

[slip]

Ok, we'll do. Thanks. I am thinking of getting the Colortune tool to check the jetting.

 

[TheCafeKid]

Ok, we'll do. Thanks. I am thinking of getting the Colortune tool to check the jetting.

Dont waste your money. The Colourtune might get you in the ballpark, especially in the pilot circuit, but with no load on the motor, its not going to be accurate. And you cant exactly ride down the road looking at the colourtune...

 

[slip]

Dont waste your money. The Colourtune might get you in the ballpark, especially in the pilot circuit, but with no load on the motor, its not going to be accurate. And you cant exactly ride down the road looking at the colourtune...

Thanks for that info, you saved me some money.

 

[toolman]

hi slip ,i have gone through what you are doing and here is what i did , same bike and mods. the stock needles are not going to do it you will be chasing carb problems and it will never run right.
go and buy a dyna jet carb kit, install the needles at the 4th position .
the mains in the kit will be too rich but the magic jet size is 127.5 for the two inside carbs and 125 in the outside carbs .
this set up will get you very close depending on altitude and you wont belive the carb responce you'll get from it.hope this works for you .
good luck ....toolman

 

[slip]

hi slip ,i have gone through what you are doing and here is what i did , same bike and mods. the stock needles are not going to do it you will be chasing carb problems and it will never run right.
go and buy a dyna jet carb kit, install the needles at the 4th position .
the mains in the kit will be too rich but the magic jet size is 127.5 for the two inside carbs and 125 in the outside carbs .
this set up will get you very close depending on altitude and you wont belive the carb responce you'll get from it.hope this works for you .
good luck ....toolman

Great, but I am a little confused. Buy the kit for the DJ needles only, and then buy OEM 127.5 and 125 mains??????

 

[Big T]

Slip,

It''s extra confusing because DJ jet sizes do not match Mikuni's

Since the bike was,presumably, running well some time before you bought it, find out how it runs before making changes

Then make changes

 

[slip]

Slip,

It''s extra confusing because DJ jet sizes do not match Mikuni's

Since the bike was,presumably, running well some time before you bought it, find out how it runs before making changes

Then make changes

I'll say! I am going to just go with what you suggest. I have to believe the PPO had it running good. I say Previous Previous Owner, because the Previous owner bought the bike for the forks, which he swapped with his 1978 GS1000. He started to fix it up, but said he just had too many projects, so he sold it. The Pods are extremely dirty, as are the carbs. I have cleaned two of teh carbs so far, and will probably do the other two tonight. With the pods being so dirty, I have to believe that air flow was restricted some, and thus maybe this is why I saw almost new plugs with black soot on them.

 

[toolman]

yes ,the only way to get it to run right is to have the needles.or go back to your air box.
you can try the jets that the kit comes with but they will be too rich. 135 and 148 are the sizes in the kit.
...toolman

 

[slip]

yes ,the only way to get it to run right is to have the needles.or go back to your air box.
you can try the jets that the kit comes with but they will be too rich. 135 and 148 are the sizes in the kit.
...toolman

I am curious, did you try the stock needles at the 4th or 5th position???

 

[toolman]

i tried everything those carbs were on and off sooooooo many times. the needles from suzuki are too lean and cant be compensated for with rich jets. its the mid range it will never be right. the differance in the two needles is huge the stock ones are very blunt at the tip where as the dj ones are very tapered and a bit longer with 6 clip settings.
if you want pods its the only way to go .....toolman

 

[slip]

i tried everything those carbs were on and off sooooooo many times. the needles from suzuki are too lean and cant be compensated for with rich jets. its the mid range it will never be right. the differance in the two needles is huge the stock ones are very blunt at the tip where as the dj ones are very tapered and a bit longer with 6 clip settings.
if you want pods its the only way to go .....toolman

You have the same setup, with Supertrapp 4 in 1 pipe? If so, maybe I will just go ahead and order them. Cause that's where the trouble was, in the mid range. Thanks.

 

[slip]

yes ,the only way to get it to run right is to have the needles.or go back to your air box.
you can try the jets that the kit comes with but they will be too rich. 135 and 148 are the sizes in the kit.
...toolman

Toolman, do your carbs look like these? Someone on the forum said that these were not the stock carbs.

 

[TheCafeKid]

Those LOOk like VM26's which would be stock. BUT the VM28s and 29 smoothbores look VERY similar. the 28's would have an accelerator pump on them and i dont see that, so Im pretty sure they're not 28s. And I dout theyre 29 smoothies because the carbs would be worth almost what you payed for the bike to begin with....I am pretty sure those are the stock VM26SS carbs..

 

[slip]

Well, I'll be darned. I do have the VM29 smooth bores. I looked them up. The slides are slightly different then the VM26's. My carb s, bracket, and chocke assembly look exactly like the ones in the diagram.

http://www.motorcyclecarbs.com/mikuni/frames/VM29frame.htm

 

[Big T]

So don't make any jetting changes until you see how the SBs perform - they're a whole different animal