'83 750E Shimming the needles

[edmondsm]

I am trying to get rid of the flat spot that is happening between 5000-7000 rpms. It feels as if the bike is running out of fuel when cruising at a constant speed. I am in the process of shimming the needles, but was curious if there is any real difference in shimming the needles versus dropping the e-clip one more slot (it is currently in the second slot from the bottom and I have been tempted to move it to the last slot)? Is there anything that says not to use the very last slot? I have noticed that even with the clip on the last slot the needle will not recess all the way into the stop. There is about half a radioshack washer width still visible between the stop and the nylon bushing. The bike is jetted currently, not sure what size the jets are though, and has a K&N filter, stock air box and Kerker 4-1 exhaust. Any ideas about if shimming will fix the surging condition would be greatly appreciated.

 

[rapidray]

If you have adjustable needles, drop the clip one position. The needle shimming is referring to stock, non adjustable needles. Ray.

 

[Guest]

I had a similar problem. It was too rich. Dropping the needles one notch helped, but only do it if the plugs are are black and fouling. Mine didn't want to pull smoothly through the mid range and sputtered if I tried to roll on. If I forced it, It would foul plugs. Now the plugs are a chocolate brown and it glides effortlessly through the RPM range. You might benefit from a Dynojet kit, though I would be guessing as to which one. I'm running K&N pods and a V&H 4-1 exhaust with a DJ stage 3 kit.

 

[Guest]

I am trying to get rid of the flat spot that is happening between 5000-7000 rpms. It feels as if the bike is running out of fuel when cruising at a constant speed. I am in the process of shimming the needles, but was curious if there is any real difference in shimming the needles versus dropping the e-clip one more slot (it is currently in the second slot from the bottom and I have been tempted to move it to the last slot)? Is there anything that says not to use the very last slot? I have noticed that even with the clip on the last slot the needle will not recess all the way into the stop. There is about half a radioshack washer width still visible between the stop and the nylon bushing. The bike is jetted currently, not sure what size the jets are though, and has a K&N filter, stock air box and Kerker 4-1 exhaust. Any ideas about if shimming will fix the surging condition would be greatly appreciated.

I am having a problem like yours with my GS1000 1980. OldVet66 is confusing me. He's dropping his needles due to running rich. And we are dropping ours for running lean?

 

[edmondsm]

I am having a problem like yours with my GS1000 1980. OldVet66 is confusing me. He's dropping his needles due to running rich. And we are dropping ours for running lean?

I think what OldVet was saying is that he dropped the needle by raising the clip. I dropped the clip, raised the needle. I might tackle this again tomorrow, go the opposite direction to find out if it is indeed just too rich. After raising the needle today there was no change at all. Might just be that it is running too rich. I will try getting the plug chop done tomorrow so I can tell for sure.

 

[Guest]

The original instructions I was given for the DJ stage three jet kit was to set the e-clip on the fourth position from the top. This was too rich for my motor causing the same symptoms you described. I did raise the clip to the third clip position from the top. This dropped the needle one notch further into the jet. If I am understanding it correctly this is restricting fuel flow causing it to run leaner. I was also told that it is very difficult, if not impossible, to get these adjustments right using the stock needles with modified exhaust and air. I believe the DJ needles may have more notches than the stock needles. At any rate, sooty fouling plugs were causing the bike to feel like it was starving for fuel through the 5000-7000 RPM range instead of what was really happening. Maybe this is where the confusion is coming from. After I moved the clip up one notch, the plugs started to burn away the soot and turned a chocolate brown color. At this point for the first time since I've had the bike, it would rev smoothly through the RPM range. Gas mileage also went up from about 37 to 40 MPG, also an indication of running leaner. My bike is a '78 with a '79 motor, VM carburetors.

 

[Guest]

The original instructions I was given for the DJ stage three jet kit was to set the e-clip on the fourth position from the top. This was too rich for my motor causing the same symptoms you described. I did raise the clip to the third clip position from the top. This dropped the needle one notch further into the jet. If I am understanding it correctly this is restricting fuel flow causing it to run leaner. I was also told that it is very difficult, if not impossible, to get these adjustments right using the stock needles with modified exhaust and air. I believe the DJ needles may have more notches than the stock needles. At any rate, sooty fouling plugs were causing the bike to feel like it was starving for fuel through the 5000-7000 RPM range instead of what was really happening. Maybe this is where the confusion is coming from. After I moved the clip up one notch, the plugs started to burn away the soot and turned a chocolate brown color. At this point for the first time since I've had the bike, it would rev smoothly through the RPM range. Gas mileage also went up from about 37 to 40 MPG, also an indication of running leaner. My bike is a '78 with a '79 motor, VM carburetors.

I have the CV carbs I'm going to mess with it today and see what happens. Lean or rich they kind of act the same. Thanks

 

[Guest]

Just got back from a 137 mile ride in 97 degree weather. The bike seemed to like it. I ran it hard at times and rode over the ridge of Mount Weather from rte. 50 to rte. 7 never under 4500 RPM, just before returning home. It's always cooler up there and a pleasant ride. Filled up on the way home and was surprised to get 43.82 MPG. The plugs still look like they should. I think I finally got the carbs right this time. It's time to do the final sync. My left mirror shakes a bit at 80. I never did get my Morgan Carb Tune, but a friend has a nice old school mercury manometer, and some big fans to cool the motor.