Trouble in the mid range

[zwells]

Hello, i realize that there have been many posts about the vision stumble and i have tried many of the suggestions i found through researching on here and it isn't helping. there are a couple of issues one is that the idle likes to get stuck around 4000 rpms with no change when i adjust the idle screw. second when i am riding it it pulls up to 3500 rpms then stumbles and then kicks my ass with power from 5500 and up. There is great power in the upper rpms but the mid range is really struggling almost catching up. I have cleaned the carbs and set them to factory specs on the pilot screws and tried adjusting them a half turn at a time and it just wont get rid of the stumble. any suggestions as to what else to try? sorry if this is repetitive.

[zwells]

I also seem to be missing the small disk filter that goes to the front carb, the PO just has it capped off?

[don_vanecek]

Gee,  I wish I knew what to tell you.  I believe I have cleaned my carbs three times since 1984, my main jets on both carbs or 130's, my carbs are still plugged, I do not have the carb fix kit (lousey dealer I bought it from in 1984 should have put it on however, but I didn't know about it) I would say I haven't done that much (I do syn em once a year) BUT I know that problem you are having, I had it also, really irratating if you going stop light to stop light.  I ran home made restrictor plates for many years, then took em off and noticed almost no difference.  maybe there is something it what I have done that may help you but darn if I know what it is. 

[Rikugun]

Trouble in the Mid Range   That would be a superb title to a novel about Visions. Or a political scientist's satirical look at the socio-economic position formerly known as the "middle class". Either way.  ;D

[Rikugun]

Do the throttle plates return to the idle stop when you twist the throttle and let it go? In other words, is there a mechanical reason why the throttle doesn't go back to idle i.e. a kinked, ma-ladjusted or dry cable. If that's not it, I'd suggest checking the sync as Don commented on and also think you may have a lean condition from something, often from vacuum leaks, but could be other things too. Do you still have the YICS chamber installed?  You might also locate a disk filter and install it to ensure the carbs are functioning as intended.

[zwells]

the bike didn't come with a YICS chamber so i had to cap those ports off. The throttle plates do return to the stop screw which is why i was confused. and i will look into vacuum leaks further. is the disk filter another discontinued part or is it easily accessible?

[Re-Vision]

You should be able to find a disk filter, all it does is provide a connection to the atmosphere. Uncapping the connection on the front carb should provide the same results as having the disk filter installed.     BDC

[Rick G]

Zwells, I ahve a used ,serviceable breather filter (disk filter) Pm if you want it.

[zwells]

Thanks for all the help guys. seems to be helping out

[Jimustanguitar]

You should be able to find a disk filter, all it does is provide a connection to the atmosphere. Uncapping the connection on the front carb should provide the same results as having the disk filter installed.     BDC

I found a floss element fuel filter on the lawn mower aisle that's been working just fine. As long as sand and mud isn't going to make it into the carb, you're fine.