What do you think

[funky]

5twins so if i increase the air pilot jet it will weaken the mix is that correct

 

[funky]

I am getting confused sorry let me see if i got this right carb theory dictates more air flow more fuel I have an air pilot jet and a pilot jet the pilot jet comes in at 60% throttle so to lean the mix on the idle circuit i either turn the mixture screw in or increas the size of the AIR pilot jet ....is this right
Also the air pilot jet in a BS34 is a Mian jet on a BS38 ???
Sorry to be stupid All the best funky

 

[5twins]

To lean the pilot or idle circuit, decrease the pilot jet size, or increase the pilot air jet size. The mix screw has a very limited effect but can lean or richen the circuit a little bit as well. It is for fine tuning with the proper size jets in place. I don't know what you mean by the pilot jet coming in at 60% throttle. The pilot jet and the pilot air jet are always working, even with the throttle fully closed, even when it is wide open. Granted, they don't add much when you're running at high speeds and large throttle openings, but they are there adding a little something.

Yes, the pilot air jet in the BS34s is a Mikuni N102.221 type main jet, typically referred to as a Mikuni small round main. The actual main in your BS34s is what is typically called a Mikuni large round main .....

 

[650Skull]

These are all the sizes of the different jets in the carbs bs34..... I have fitted new float valves and Gaskets set the float hight to spec and checked with clear tube to the float drain, Just waiting for new main jets should be here tomorrow

All the best funky

My jets are the same as these.

Just clarifying because you had posted after this post and before mine

 

[peanut]

...apologies for the misinformation Funky I should have read up on the BS34 before responding.
No wonder you haven't been able to eliminate the sooty plugs .I just assumed that the BS had an adjustable air screw like a BS38.

The link that I gave for Pedmoto has all the jets you should need at the very cheapest prices I have been able to find.

 

[peanut]

oops double post . This site is screwy this morning or very slow refresh rate on my browser

 

[650Skull]

peanut.........Go to page 27 of "Carb Guide" and read the small print under the graph. Will answer your question. Also posted in #4 on page #1 in this thread

Go to http://www.biker.net/80_650g_parts/650g_parts%20main.html and look under "Carburetors" and the fish file has part no's and an exploded view and jet sizes. Put all this info together with 5Twins post and you will have your question answered............Hope this helps

 

[funky]

Hi Chap Thanks for the post very informative. Mr Skull My bike is jetted i believe for the us or canadian so thats why your is probably the same but for me thats not suitable for my setup i am a few meters above sea level where i live and obviously different climate.thanks for the posts.

5Twins again you have helped me I was having trouble finding a BS34 Air pilot jet once you bought the fact to my attension that they are also used as main jets on the BS38 and are call small round jet I found lots of them and have ordered 3 different sizes Thanks again.

I re jetted the main and i am almost there my logic being that if i lean off the air pilot to the point where i have to use a little choke to start that must be about right. I will then deal with the pilot jet under the rubber bung near them last if need be. I am only dealing with each circuit in turn or it gets too confusing.
will keep you all updated on how i progress .
All the best Funky

 

[peanut]

peanut.........Go to page 27 of "Carb Guide" and read the small print under the graph. Will answer your question. Also posted in #4 on page #1 in this thread

Go to http://www.biker.net/80_650g_parts/650g_parts%20main.html and look under "Carburetors" and the fish file has part no's and an exploded view and jet sizes. Put all this info together with 5Twins post and you will have your question answered............Hope this helps

thanks for the links but I thought the object here was to help the thread starter not me

I have no interest in the BS34's I have the BS38's remember.

 

[5twins]

One more thing you guys need to know - there is no "air" screw on a BS carb. The mixture screw is a true fuel mixture screw, regulating fuel flow, not air. Opening it more adds more fuel and makes things richer, closing it reduces fuel flow. But as I said, it's effect is limited. It won't compensate for the wrong jets.

Fuel flow from the pilot jet, or more correctly, the fuel and air mix from the pilot fuel jet and the pilot air jet, enters the main bore through 4 tiny holes. Three are clustered together and come directly from the jets. The 4th is off to the side (BS38s) or on top but spaced away from the other three (BS34s) and comes from the mix screw. You can adjust the flow on that 4th hole with the mix screw. Altering the mix strength from the other 3 can only be done by changing jet sizes.

 

[650Skull]

Know you have 38's. Posted the info for you before you corrected you previous post #45. You assumed the 34's were the same as the 38's.

My post may help others to cross reference when they read this thread.

 

[peanut]

thanks guys for the explanation about the BS34 .. it must get frustrating keep repeating it over the years but to be fair information and faqs on this site could benefit from a complete overhaul ...collating ,editing and reorganising to make it easier to find.

At the moment there is a lot of unedited stuff posted all over the place and sometimes it takes owners a bit of detective work to search out the relevant bits and piece together if they are unfamiliar with the marque ,bikes generally and the site.

Many enquiry threads that have subsequently developed into an important reference source have an unrelated thread title and are near impossible to locate using the search feature unless you know what you are looking for and where to look.

 

[TwoManyXS1Bs]

I know whatcha mean, peanut. I've tried to remember certain buzzwords and phrases to help refind important posts/threads, 'bout ready to lose my mind. I've 'subscribed' to important threads, they now number over 1,000. Well beyond sanity's limits.

Just for fun, I just tried to edit the title of one of my threads. Didn't work.
So, threads with titles like "Halp! Whut's wrong" will stay thataway.

At least gggGary has been adding useful tags/buzzwords in his important posts...

 

[TwoManyXS1Bs]

One tool that I've found useful is to list a member's posts. It shows the first sentence, for each post.
Unfortunately, it only goes back 500 postings.

So, the gold posted by 5twins, xsleo, grizld1, gggGary, 650Skull, and others, is out-of-reach...

 

[peanut]

One tool that I've found useful is to list a member's posts. It shows the first sentence, for each post.
Unfortunately, it only goes back 500 postings.

So, the gold posted by 5twins, xsleo, grizld1, gggGary, 650Skull, and others, is out-of-reach...

yes thats a great shame. I'm sure just about all the information you would ever need is contained within a thread somewhere on this site .

I frequently come across some vital bit of experience or advice but as you say there is just too much to keep track of.

My fear is that one day it will all be lost forever to some catastrophe or other which is what happened to the Lambretta Club GB recently .

 

[I am Carbon]

yes thats a great shame. I'm sure just about all the information you would ever need is contained within a thread somewhere on this site .

I frequently come across some vital bit of experience or advice but as you say there is just too much to keep track of.

My fear is that one day it will all be lost forever to some catastophy or other which is what happened to the Lambretta Club GB recently .

what Ive been doing is "copy and paste" info that's worth keeping in notepad then saving in documents. copying pics too.

 

[TwoManyXS1Bs]

what Ive been doing is "copy and paste" info that's worth keeping in notepad then saving in documents. copying pics too.

Same here, but my tablet is about to (*burp*) burst...

 

[peanut]

Ha ha ...great minds think alike

Trouble is now I have so much saved stuff for my car, campervan, bike and scooter , photography, etc etc that its becoming just as difficult to locate stuff on all my back up drives lol

 

[funky]

Well i am glad you have the wisdom and energy to repeat your posts and pass on what you know I can say without any problem that every one here has helped me very much and in essence its true love indeed it is ... because it is without any payment or negative consequence its unconditional shared wisdom we all save time and money from each others failures and results, we jointly assist the best we can, and its not long before we get a newbie and then he or she starts posting advise to others as he or she learns Its a true community of beings, from all walks of life helping each other,we have generally never met or even know what a person looks like it crosses boarders religion ethnicity cultures it knows no boundaries its a beautiful thing.
Thanks dudes Im getting emotional here
I can just imagine some yank chewing Tobacco he spits on the groung and winks at me and says "Don't get Mushy Kid,,,,, It ain't no big deal ya hear, All you got to worry about is getting that there motor cycle running like a dream and hiiting the road " He then takes a swig of Whisky strait from the bottle kicks his XS into life and rides off
Sorry for the sterotype lol no offence meant hopefully none taken
All the best Funky

 

[TwoManyXS1Bs]

...I can just imagine some yank chewing Tobacco he spits on the groung and winks at me and says "Don't get Mushy Kid,,,,, It ain't no big deal ya hear, All you got to worry about is getting that there motor cycle running like a dream and hiiting the road " He then takes a swig of Whisky strait from the bottle kicks his XS into life and rides off

Sounds like you've been to my neck of the woods.