BS 34 carburetors

Post #8 page 1 I posted a pic of my carbs that showed the different setting for each pilot screw.

Been a while and many pages later.
Yes Sir Sorry about that I confess this has been a bad performance by me.
I have never had much carburetor problems over the years 4 - 5 times over 40 Years

.So I Tried to find electrical Problems for to Long --The proverbial " Lost in Space " .. Where one can use a different Methodology . At least when having done it many times And on an old bike with substandard wiring there are electrical problems ( Everything is a problem ) I had a weak old battery for starters .
One can measure and try. If not working try something else. The quick fix Use parallel wires and Whatnot.
And then when I found the Carburetor Problems I did not clean it Properly ( Had No compressed Air then )
And then started to adjust .and shift Jets without reading the manual. ( Could not start it on one Cylinder )

A learning curve here ..Jump in and try to fix it was not the right method. This Time
Fingertip ratchet .CAR boot sale 3 $
Sometimes tools can be pretty Or do I have a defect between the ears , .No pretty tools back in the seventies .
Good quality tools but no one bothered making them shiny or flashy perhaps high end was available and for Fine mechanics ,,
But I have not seen such
I don't believe this is old 80 ies or so Nor extremely High end .. Which would be step less which this one is not -- Fairy good though It has the rounded bits Ball head hex bits so one can use it at an angle
Spotted Painted Metal casing though I have Impact screwdriver from 80 ies with the same type looking metal box



In the process tweaking the mixture screws and moving the needle
For mixture screw a flathead bit 2 inch long ( 50 mm ) is good to have But these are hard to find buy.
On the way out .Cant buy them.
I was at a big hardware store For professionals He did not have them for sale either .
But he had a personal stash in a shop metal drawer. Believe it or not he gave me 3 x
Made me happy.
I have read the manual Now
Clip is in the third slot from the top Still a bit rich at full throttle coughs at 4-5 a little .
But I believe I will keep it for now.
Second slot did not work at all.
Having that bit and the wrench for spark plugs i adjust. Out on the road. If i need to

Fumbled again in the last owner segment ..All of a sudden white plug on the left side.
The hose for opening the petcock was cracked at the connection at the back and broke off. Probably been cracked a long time

So if you see those bits it can be a good idea to buy a couple. Having available Here they are disappearing .
I Painted with yellow paint on other things .So I also marked bits with paint One side of the hex yellow So one can se better how much turned
Some Hints that can help someone

Get the JIS screwdrivers or bits. ( Not so Expensive ) $ 10 $ 15 $ 20 $

When trying to lose a screw pay special attention so that the tool is exactly in line with the Screw
NO Angle in NO direction NO way and No how EXACTLY IN LINE
That is not so important for all screw heads like Hex or Allen have tools for angles or slotted screws even

Push the screwdriver inwards hard -- In my case as much I can .Perhaps holding with the left hand on the back
And then try to loosen it Pay attention so it does not slip trying to come out of the slot + .If it slips Stop immediately.
Reevaluate considering other methods heat lubrication or so. Impact tool but again -- EXACTLY IN LINE
pushing inwards
About my favorite tool for carb screw and jet removal is a T handle holder for my screwdriver bits. With it, you can push down really hard and turn at the same time .....


Some really crusty jets I managed to remove recently. I used penetrating oil and heat to aid in the process .....





Ordered a set 40 Pilot Jets I will install se what happens have 42.5 in now which I Believe is stock
Have 45 in House
Plugs on the dark side
Runs perfect everywhere else but not 2 -3 k range. Could live with it but will try this
Have tried the mixture screw.
For once going for perfect for all RPM s
Pilot Jets arrived and Installed --- appears better ---Good even ..Need to run some more and look at the plugs
Both mixture screws out 3 Turns.
Needed adjust the idle Screw

The tools
Flashlight finding the dropped items
The Mirror for finding the inner bowl screw holes. My eyes are helped
2 x JIS bits for loosening and tightening ..pressure on the end and the wrench above turning works fine
The longer one for the most places but at 2 or so the shorter works best
Once loosened turning by hand .
A flat bit for the Pilot and a 1/4 inch wrench Perhaps not need the wrench

The plastic container for the petrol coming out
And collecting the parts .
I forgot install the rubber plug but noticed it in the corner before the bowl was tightened



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Better 100 km Ride last night .Not much darkness this time of year
Got difficulties shifting out on the road .The clutch locknut had come loose
Roadside repair .Had the tools with me
Adjusted the Cam chain , Should have done it before.

Left slightly whiter maybe some fine tuning
But the stumbling between 2 - 3 k appears gone
Not had vibrations for many years but felt some now in the right handle ( Not much ) It was some rain last night so it can be other things
Run some more check mileage and maybe lean out the right On the mixture screw

How many miles are on those plugs? They look rather old and beat up. I've found the XS is rather tough on plugs, wearing them out in 3 to 4K miles. They still work but aren't "fresh" anymore. The bike starts easier, idles better, and overall runs better if I change them. To judge the wear, you really need a brand new plug you can compare the old one to side by side. Since the plugs burn relatively clean, they won't look worn by themselves, but what happens is the center electrode gradually wears shorter. Like I said, you wouldn't notice this unless you have a new plug on hand to compare to .....


Yes Sir good idea been sitting there 4 years
Have a mileage 18/ 7 2020
And today
in total --- ca 8400 Km
5200 miles

ca 2400 Km per year .. late in 2020 and not much yet this year

Have a new set at home
Wondering if a synchronization shall be done after Pilot jet change

I have the habit adding a little oil sometimes installing plugs so it not shear the threads.
New Plugs ca 100 Km
Better again Vibrations more or less gone again
Left is brighter opened the Mixture Screw 1/4 Turn See what happens
Dont Know why it is not sooty on one half



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With today's cleaner burning fuels, it usually takes several hundred miles before new plugs color up much. Changing the pilot jets shouldn't affect the carb sync but you probably do need to re-set the mix screws. Since you went smaller on the pilots, you may need to open the mix screws a little bit.
With today's cleaner burning fuels, it usually takes several hundred miles before new plugs color up much. Changing the pilot jets shouldn't affect the carb sync but you probably do need to re-set the mix screws. Since you went smaller on the pilots, you may need to open the mix screws a little bit.
Yes Sir set them on stock settings ..Believe it was 3 turns out if i Recall right
left now on 3.25 turns out
Actually, since they came capped over from the factory, there never was a setting spec given for the BS34 mix screws. That suggested 3 to 3.5 turns out is just a setting we found that usually works well on stock (or near stock) bikes. If you end up increasing the pilot jet size then the mix screws often work well set around 2.5 turns out. But, every bike wants what it wants, so these settings aren't etched in stone. Consider them just as a starting point and fine tune from there.