BS 34 carburetors

jpdevol

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Please give info on what year and what kits is right should I need them.
The kit looks to have the correct parts. The 3L1 shows a Euro '79 model. But as Jim says, your carbs look like my '80SG BS34's. The parts listed in the kit (attached) jive with Euro BS34's
 

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gggGary

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In the US brass floats and hex drains are 80's
how is the fuel fed in? IIRC the euro version has 2 petcocks and the fuel comes in on the outer side of each carb.
Use heat on the angle iron screws, it softens the thread locker goop.
Good use for a gasoline torch..... Just KIDDING!
 

Vincenthdfan

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In the US brass floats and hex drains are 80's
how is the fuel fed in? IIRC the euro version has 2 petcocks and the fuel comes in on the outer side of each carb.
Use heat on the angle iron screws, it softens the thread locker goop.
Good use for a gasoline torch..... Just KIDDING!
Oh how I wish I'd seen this post a few days ago.

Of the 2 separate 1980 Specials I'm cleaning carbs on, I know one set has definitely never been apart before....those L bracket screws wouldnt give up the ghost without vice grips!! Had no idea they'd been loctited...dont know why that didnt occur to me?

1677519025235.png
 

gggGary

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Oh how I wish I'd seen this post a few days ago.

Of the 2 separate 1980 Specials I'm cleaning carbs on, I know one set has definitely never been apart before....those L bracket screws wouldnt give up the ghost without vice grips!! Had no idea they'd been loctited...dont know why that didnt occur to me?

View attachment 236489
You've got those looking beautiful!
 

Jan_P

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In the US brass floats and hex drains are 80's
how is the fuel fed in? IIRC the euro version has 2 petcocks and the fuel comes in on the outer side of each carb.
Use heat on the angle iron screws, it softens the thread locker goop.
Good use for a gasoline torch..... Just KIDDING!

One petcock on the left side .the type opening with a suction hose from the intake manifold.
Planning to replace it.

Heat is of course one way forward. I should have thought of that and used it more -- sooner.
I was not able to loosen them first time on a set 4 screws with any pliers or vice grips
Impact wrench Pipe wrench nothing I had home . Big problems Drilling them out.
Got lucky not destroying anything.

Second time --This time I had better luck Going for impact wrench ( New one ) and nut pliers directly
And getting 2 off --Decided to stay when ahead instead of using force and damage the parts

Damaged a clutch basket once when the weak holder tool folded.
e .bay $ 100 used.. + Waiting time
 

5twins

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Brass floats and drain bolts on the bottom of the bowls (as opposed to drain screws on the side) indicate that is a 1980 carb set. Jetting and gaskets were the same as all the other 650 BS34 carb sets, so those rebuild kits you linked to should be fine.
 

Jan_P

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Took out the motorcycle Yesterday fresh 137.5 jets on the bench
Inside was 132.5 So I should have done better documentation.
Found some 135 s at home that I installed.
Strong sunshine so I had problems hit the screws back on the bowls have been thinking about making
some fixture hitting it better

Tried to start it without much else a couple of priming kicks 3 - 5 and 3-5 more it started .
Unusually quick . Sounded good it was shooting in the exhaust at idle a bit And the idle was to low so it stalled.
Old fuel . shall drive some before more adjustments. But they are needed ...Will go through the Tech Carb Manual.

Went around the block Felt strong ..and all good. More to do on the carburetor tuning.
Tomorrow I ll report it to the authorities taking it into use It is mandatory for the traffic Insurance.
Go to the gas station pump the tires. Filling up gas

Have a replacement Seat cover that may not be the right one Or are they tight ??
But have 2 seats that is OK
Can cracks in the old Stock Seat covers be repaired
 

Jan_P

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Better on Top .But still stumbles at 2 k .I believe still to rich
I have not done adjustment on Mixture
Not sure now with this substandard wiring.

But got traffic Stopped .. Routine-- stopped many . Check of drivers license and .. On Line that the bike was registered and so
Had to do breath alcohol test at the roadside.

I joked with her the Policewoman -- Who can afford any Spirits these days ..and drive around. cant be many.
But she said last time there .After one minute the first one was drunk. Fine weather and Close to the Beach but not many people
A bit To cold so the restaurants was not even open.
But maybe the unpredictability in the stops is a factor.

Perhaps the first time in my life that these situations did not start with a Harassment or Abuse. No fines No problem Carry On
Perfect riding weather .. Trees with blossoms cherry Beautiful Scenery
PRIME TIME LIFE.
 

650Skull

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Copd often pull me over to breath test for alcohol. Driving a ute with tool boxes on the back is the magnet for me.

I presume you have had a squizz at Hans's site and looked at the 3l1 Parts manual.

Has the BS34 Carb showing the non US needle/jet and pilot crew. There is a slight difference between the Japanese main Jetting recommendation and the European 3L1, (euro 3L1 jet size recommendations are the same a the US non Adjusable needle set up), recommendation. Nothing to write home about but interesting as to why. Also the Needle is the same no but has an added number at the end.

Was there a slight change due to the different mufflers being different between the Standard and Specials?????.................didn't do that on the US 78/79 Models. The jetting was the same for both standard and Specials.

Another mall point is the needle hold down plate screw spring washer isn't included in the 3L1 semantic.............

Good to see your getting close Jan


4E3-3W6-3U6 TEXT copyright.jpg
Euro BS 34 3L1 Carbs0404 reize 2500.jpg
Euro BS 34 3L1 Carbs0505 reize 2500.jpg
 

Jan_P

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Adjusted the mixture screws.
By some reason I could not kick start on right cylinder no idea why at the moment
Synchronization ?
I set it last year spot on but perhaps need to redo it.
Can have an air leak
left OK
I had it idling on both cylinders and adjusted until it changed rev and ended at 2.5 turns .( From 3 ) On both .carbs
Tested Just around the block But impression was that the stumbling at 2 k was almost entirely gone Much better in any case
See what happens.
Starting is fine on kick start.
 

Jan_P

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Fell down from the cherry tree again ..setting up a bird house Climbing down a branch broke and i got airborne
Not so high up.
Landing on the ladder and rolled down onto my back .But I believe nothing is broken.

Bike runs better but still is to rich at 2 -3 k I have oversized pilot and Air jet
I had problems getting it to start and run on the one Right cylinder.
Valves are checked not long ago
I did sync last year Spot on ..
Plugs New
Please have opinion why it is more difficult on one side If anything obvious

Can it be that below ---I don't believe I Checked that it was open with the strong light.

1684335511294.png
 

5twins

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Yes, it could be a plugged choke jet on that carb. Checking it is easy enough .....

ChokeJet2.jpg


Cleaning it is another story, lol. It is pressed in and can't be removed. You need compressed air to blow it clear. And being that the jet is a good 1" or more down inside that bored passageway, a needle tip for your blowgun is a big help. It lets you place the tip right on the jet and get a good, strong blast of air through it .....

Blow Guns.jpg


I have a set of these in different sizes. Great for carb cleaning .....

NeedleTips.jpg
 

Jan_P

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Thank you Sir
I did buy a small Compressor. Not available before.
And a kit of accessories .. Better possibilities now Should be able to se if it is Clogged
And clean it.
 

Jan_P

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It helped
I had a another set and took a Bowl and Cleaned .. took off the right Bowl and used a LED flash lamp What the H.. l There is light No Problem
Tried to start It was the left Cylinder that was problematic I had made a Mix up
The good with the bad was that I had one Bowl on the bench that worked 30 minutes ago

Took down the left and it was not entirely clogged I could se the light of the Flashlight.
But the hole it was about half the size when clean.

Replaced and then got first kick start on Both cylinders Need to set the idle when warm .And see what more got affected

Dropped a screw behind the cover and under the chain but after some problems and mirror + flashlight + magnetic tip Screwdriver got it out.
 

Jan_P

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Synchronized and set the Idle --- Better again .. Short test ride ..8.5 9 of 10 Over the entire rev range
Mixture screws at 2.5 Se if that needs to change. Need a longer test ride.
Maybe go down on pilot jets, and air jet.

Learned a lesson here .Different methodology from electrics Should have cleaned better from the start.

# 173 picture is from the tech manual .. not mine
 

Jan_P

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Out on a ride yesterday about 150 km . had the mixture screws at 2.5
Wondered what would happen if i Open 1/4 turn to 2.75 out on the road after Lunch
A mistake .. Had to set them back on the road and When I got home The left plug was slightly darker .The right OK .A bit on the dark side .But good enough
Adjusted left only ..Running on one cylinder which works cold and then test ride .Getting it warm for adjustments but It has always been difficult start on One cylinder warm At times on 2 Cylinder warm also With points or as Now Boyer Bransden

So grounding one plug and starting on the other hot --cant do it Splutters and some smoke in the carburetor but dont start . When hot --Cold it stats ...gave up Will take out the plugs after some riding see if they are closer
Bike is charging If adjustment on mixture don't do it I will flip the ignition wires with caps and plugs .

Is there any reason one cant have different mixture screw setting 2.5 on right and 2 .25 ish on Left Now
As long as the plugs looks the same

Maybe I need to go Down on pilot Jet to stock and stock air Jet .But Was hoping to ride this season without messing with it.
 

Jim

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Is there any reason one cant have different mixture screw setting 2.5 on right and 2 .25 ish on Left Now
As long as the plugs looks the same
No reason Jan. They are there for fine tuning each individual cylinder. Make each cylinder happy and don't worry about the number of turns.
 
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