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gs 1000 carb issues

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I recently put an 8v gs 1000 engine in my 78 gs 750 frame. The guy who i got the engine from said that it might have been bored out to 1100 but he wasent sure. It has emigo pods, accel coils and plug wires, and dyna ignition it also has a 4 to 1 exhaust system. I am using the same carbs off of the 750 motor (I beleve that they are vm 29s but im not positive what ever came stock on a 78 gs 750)the jetting for the 750 was #15 pilots and #105 mains the needle was in the middle position all i have done so far is put a 112.5 main in and lowed the needle one step it runs good at full throttle but has a huge dead spot that feels like its in the pilot circuit. so i was curious what others are running with the same motor and mods i was thinking about going up a step with the pilots but i wanted to ask here first. So if people can let me know what there running with a stock displacment engine and a bored out engine that would be awsome any advice would be much appreciated. Thanks Robbie
 
You are probably still too lean on the main Lots of trial & error on jetting
keith has more experience with jetting VMs. Raise the needle another notch & go to 115 or 117.5 & see what the plugs look like
 
Do the vm 26's look pretty much identical to the the vm 29's? I looked on sudcos site at the picture of the VM29's and they looked the same as the carbs on my bike except for one thing, part number 87 on the diagram which is called the the jet block. I recently changed the needle setting and i dont remember seeing that part in my carbs. If i do have VM26's what would be a good base setting for those carbs with my bike? I am about to go and get a set of #20 pilots to see if that helps and i will probably change the needle setting again. thanks for the help I'm sure I will need a lot more in the not to distant future :oops:
 
The easiest way Look at the float bowl the VM29's are a preformance carb, never offered stock. they have a large nut on the bottom of the float bowl to make jet changes easy
 
This was written by Keith as I remember

Stock mains are #95. Pilots are #15. The stock needles usually have their clips in the 3rd position from the top. The floats should be set at .94-.95" (manual calls for .90-.98".) The side air screws are generally at 2 turns out and the pilot screws (underneath) are generally 1 1/2 to 1 3/4 turns out (with pods). The pilots need fine tuning for each cylinder and the side air screws should be set for the highest RPM possible and then the idle set correctly with the idle screwknob.
I would have guessed 125 Mikuni mains and 17.5 pilots would be close? Raise the needle 2 positions from stock? Do what the plugs tell you at various throttle positions. Actually, I recommend a Dynojet jet kit, p/n 3304. Try putting in their 138 mains and set the needle clips at the 4th position from the top and use the stock pilot jets. Remove the float bowl vent lines. Adjust the air and pilot screws as I said and you should be good or close to it.
 
Like Lynn says, look at the bowls. The 29's have the large bowl bolt to access the main jet. Send a pic' if you can to remove any doubt.
If you have the stock 26's, again, as Lynn said. I really like the DJ kits but with the cheaper pods you may be able to make the stock jet needle work with the e-clip in the bottom (5th) position.
As an important part of jetting, you must vacuum synch these carbs after every jet needle adjustment. If the carbs aren't synched, you can't get accurate plug reads or get best performance. I also suggest replacing the manifold o-rings.
 
Here's a link to some info on the 29mm carbs - scroll down and you'll see a couple of pictures.

http://www.z1enterprises.com/reference/z1-carb-guide.aspx

If the smoothbores were sold for the GS application, they probably have 2.0mm slide cutaways - I've heard arguments stating 1.5mm is better on the GS's - but I have no first hand experience with the 2.0 slides on a GS.
 
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