Discussion in 'The Garage' started by Benjamin, Aug 31, 2009.
1981 and mikuni BS34s
These are my standard questions and please read the carb guide 'till your eyes bleed. It really, really needs to be read my every BS34/38 carb owner.
How did it run before you took them off?
What is your float set at? Should be 22mm for '81 with plastic floats.
Is fuel flowing in the fuel filter properly?
Rubber plug over the pilot jet?
Float needle free moving?
Are the diaphragms torn?
Mix screw properly set using the dead cylinder method?
idk how to get to the mix screw. its getting plenty of fuel. yes it did run but depended on the choke. dont know float set. dont know jet sizes. rubber plug is over pilots on both. diaphrams good. needle is free moving
im very amature.
Well amature is fine. At least you are asking and this forum is a good place to learn.
Do yourself a huge favor and please read the carb guide and this one as well: http://www.iwt.com.au/mikunicarb.htm
Go piece by piece and don't rush. Learn the parts, what they do, and it will all mesh together. I promise.
what tool could you use to get the mixing screw block off?
A self tapping sheet metal screw. Just get it in a little. It gives you something to grab and pull it out.
so its not threaded correct?
No, just tight. The carb guide tells you all of this. It was written by 5twins and Grizld1.
Ok im gonna try. Ive been running back and fourth between the house and garage between threads to try to fix this thing.lol
Ya, it won't happen overnite though. Don't rush it. If they break, then...well.
The mix screw is threaded into the carb body but it's covered over by an aluminum plug that stops you from getting at it. That plug is what has to be removed. You drill a small hole into it, thread a suitable sheet metal screw into it, and pull the plug out.
I actually carefully drill all the way through the plug. Take care to stop AS SOON AS you break through the plug. If you keep going, you'll drill into and destroy the screwdriver slot on top of the mix screw. I blunt the end on the sheet metal screw so it doesn't dig into the mix screw and screw it in. It hits the top of the mix screw and as you keep screwing it in, it pushes the plug up and out for you.
The mix screw needs to be removed to properly clean the idle circuit. That may be your problem.
I got the block out and i'm in the process of putting the bike back together to try to tune r up some.
Thanks 5twins. I should have been more clear on that.
Sea foam at most places it's on the same shelf as Gumout, STP. Along with many brands of carb cleaner.
It may be in with the oil additives.
those of us that run viragos with hitachis know about seafoam also you can soak your carbs in pinesol or lemon juice to clean them and they wont hurt any rubber parts
I'm running a virago with hitachi's soaked in Pinesol 1:2 withwater did an excellent job and use Techron as a fuel additive to insure all circuits are clean and stay clean.
Does the lemon juice brighten the aluminum - if so I'd like to get them a bit shinier.
Viragos look pretty but are an absolute nightmare to work on. They all belong in the crusher as far as I'm concerned, lol. The shop wanted $1100 to fix my buddy's (bent valve). We did it for about $100 but I hated almost every minute of it.
really i work on all my stuff and i dont see much differance in my 83 920 and my 79 xs650 at least difficulty of repair which by the way i dont have to do much after the first year i had the 920. i just fixed the problem areas before it caused me a problem. the 650 is much the same way
Well--I cleaned the carbs,checked for a vacume leaks, checked the diaphrams, neadle valves, jets ect etc. I gave up. I gave up and brought it ton a mechanic. After a week with two mechanics they cant seem to find the problem. They recommended me taking to Yamaha dealership who has old mechanics.
Theu believe it is an electrical problem perhaps with the CDI box.They dont want to just change parts though. Monday I will drop it off with Yamaha.
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