fine tuning advice

One thing that cant be stressed enough is to be sure the carb bowls are LEVEL ! use a small level to check each and every time you do an individual carb.,"looks Level" isnr going to cut it.Also when you remount them on the bike make sure they are level before tightening the carb. mount clamp screws,doesnt do any good to go thru all the trouble to get 'em right and then mount on the bike with the bowls angled high or angled low.Use the Level,you'll be glad you did.

Before mucking with the carbs, I would personally investigate other possible causes for the plug fouling. Why not swap the #1 spark plug wire (#1 is the one that is fouling) with the #4 spark plug wire. Both the #1 and #4 plugs fire off the same coil. By swapping plug wires, you can troubleshoot this issue to tell if it is ignition related or not. Ignition is FAR MORE LIKELY than carburetor although the problem MAY be carburetor related.

the first day i had my bike running it ran EXACTLY like how you are describing. bogging at low rpm, hesitating above 6000, and not the power i expected. today i put some rubber caps on the ports that connect the 1 and 2 carbs, and the 3 and 4 carbs (i think they are vacuum ports). started the bike up, went up the street, SO MUCH MORE POWER all the way to 8500 rpm, you wouldnt even believe its the same bike. if those ports on your bike are open, close them up and see how it runs.

*EDIT*
seeing as this is the first bike ive ever worked on, and also the first carbs ive ever tore into, my guess was wrong that these were vacuum fittings. and according to the following site, you should not plug them. but why does my bike run so much better with them plugged?
www.wgcarbs.com/index.php?option=com_con...view&id=17&Itemid=32

great, i just made a huge post and then it told me kzrider was temporarily unavailable......
ill make this one shorter.

It looks like I've found my issue with the carbs! Now if anyone saw my posts before, I was having ignition problems pretty much right after this had happened, so i put off carb stuff. Turns out I had both a carb and ignition problem sumultaneously. Now I have great spark and electronic ignition wiht the WG coil mod. Both have made a huge difference.

So today I took the carbs off to rebuild and clean as the bike wasn't running on all 4 cylinders consistently.

On the number 1 carb, upon taking the pilot jet (50) out of its slot, the threaded jet underneath it (not sure what that one is technically called) had come unthreaded! It was just floating in there assumingly giving me uncontrollable fuel flow. It was one of those "you have got to be kidding me" moments.

So I believe I have my carb issue figured out. Now since I have the carbs out, I have a couple questions. I am going to keep my stock airbox setup, but I have the 4-1 Vance and Hines installed with full baffle. Do I need to re-jet? Now is the time if I want to. It has 90 mains and 50 pilots. That's how they are labeled. Can I get away with stock jetting? How should I set up the air screws to start with? Any other settings to adjust for this?


This is on my 1978 650SR.

Thanks!

Since only one cylinder seemed to have a problem (the one with the plug that kept getting carboned up), and that cylinder had the problem carb, I would just put things back together and see how it runs. If nothing else, that will help you establish a baseline from which to work if indeed you need to change anything. Ed