Carb troubles (and introduction)

[a747freak]

Greetings forum,
My name is Steve, i bought my Vision in April and its in rough shape.  I'm trying to get her road worthy again.

I've been riding for about 7 years and this is my third bike.  My two previous bikes were both from the 80s as well, and have done a decent amount of work on both but I'm by no means an expert.  When it comes to the carbs and the fuel air system, one thing I've learned is it has to be in good shape with no leaks for the best performance.  Since not much about this bike is in good shape, before doing anything else this is what I've done:

Rebuilt the carbs with a kit, new jets, gaskets, etc.  I backed the mixture screw out 2.5 turns, as I read in another thread on this forum.
Replaced the intake boots with brand new ones (ebay purchase, shipped from Poland I think)
Replaced the battery with a brand new AGM
Replaced the fuel line
Replaced the air filter
Washed out the air box

Now the carbs were very gunked up when I took them apart.  The foam inside the previous air filter was falling off and getting sucked into the carbs.  When I first put the carbs back on the bike after reassmbly, I hadn't yet replaced the battery and had to jump start the old battery but it started right up.  I took it for a ride for a good while and it didn't stall on me at all (even though my riding skills are rusty).  However, after I killed the engine, it wouldn't restart for me.  It was getting dark and I didn't have the headlight connected so I called it quits for that night and ordered the battery.

Before the battery came, I tried starting it a few times while jump starting and could not get it running.  I installed the new battery and still couldn't get it to start, but it did kick over once or twice for me.  Fast forward to today when I got it easily started with start fluid, again took it for a ride and had no stalling issues or anything, parked it and couldn't get it started again (I didn't try starter fluid again since I knew that would work).  During both rides, I also noticed that acceleration wasn't that smooth.  If I yanked hard on the throttle, it would just about cut out on me and then the RPMs would jump hard.

Any ideas of where to start troubleshooting?  Much appreciated.  Glad to have a bike again, but they are such a pain!   ;D

EDIT: Just to add, it idles real nice and I set the adjustment to have it idle at 1500 RPMs.  It's like once i get the damn thing started it runs halfway decent unless I yank on the throttle hard.

[Kenny]

 Hi Steve,
    Welcome to the ROV site . Lots of info here. Many of us have been through the same process , when working on these machines.
   What year machine is yours ? Were are you located ?
    Did you soak your carb bodies in Gunk or something similar - these carbs have many small passages that are a pain to get clean especially with todays fuel . Do you have a fuel filter installed in your system ?
  Some thing you can check is to remove the top of your air cleaner open the throttle and check that you have the same amount of fuel squirting down each venturi . Also most of these bikes have their own starting procedure both of my 83's need a couple of twists on the throttle and full choke when starting from cold . You may also try going to Prime on your petcock as the vacuum setting on the petcock may be u/s.
   That's all I can think of at the moment , I hope this helps. These bikes are a lot of fun when they are running right .
       Cheers Ken S.     
 

[a747freak]

Hi Ken,
Thanks for the reply and I'm glad you mentioned twisting the throttle and full choke - I figured that out by accident today when I went to start it, and she fired right up.  I did soak the carbs in Berryman's dip over several days, and then with several cans of aerosol carb spray (hope nobody on here is an environmentalist!).  There is a fuel filter installed.  I was surprised at how easy it started up, part of my issue may have been learning that routine like you suggested.  The acceleration is still very rough but I suspect the carbs just need to be synchronized.  I took it up a hill by my house and the bike struggled to stay running until I reached a certain threshold on the throttle (I would say about 1/3 to 1/2), at which point it felt like it had full power.  There may still be some clogged passage.  It could be my imagination but it seems to be getting a little better each time I ride (keep in mind I bought it in April and have only been able to ride for any length for the past couple of weeks.  Only riding around my house for now, short 1-2 mile trips).

I am located in Pennsylvania (USA) and my bike is an '82.

[Kenny]

  Hi Steve,
Glad to hear you are making some headway with the 82. I like your  "Handle" one of the wide bodies I am endorsed on is the Boeing 747 100 & 200 series The other is the Airbus A310-304 the Canadian Forces have five A 310's in various configurations  MRTT, (multi role Tanker Transport) another is a VIP , and a couple of Combi's (freight & Pax). I spent 21 years wrenching on the 310 in Trenton On. and retired a couple of years ago and moved to British Columbia .
   That's it for now.
    Cheers Ken S.     

[The Prophet of Doom]

I suspect the carbs just need to be synchronized. 

You *HAVE* to sync the carbs. At least every time you touch the carbs in any way, preferably more often. 


No point in doing anything on unsynced carbs as you will just chase your tail. 


You'll want to check float height before syncing.  Procedure in Haynes.  And are you sure you cleaned the emulsion tubes? They are very prone to getting clogged and have a big effect over a wide rev range.  You want every one of those holes clear.