Float height discrepancy

Mitch81special

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I'm trying to tune a carb for the first time, bs34 on a 1981 SH. I have looked through the guide and a few threads, the carburetors from the grave thread is a great resource. I have it running but it still just doesn't seem quite right. I just now checked my float heights and the left is low. I'm wondering if I should be pulling it apart to remedy it.

Some background info
I have a 45 pilot / 135 main needle set to 3rd slot from the top. I synced the carbs with a monometer and set the mixture screws to 3 1/4 turns out. I did measure the float hights when I had the carb apart (22mm).
 

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IMHO those fuel levels look close enough to not create an issue with how it runs. What does "not quite right" mean?
Did you remove and clean the needle jets.
ditto pilots rubber pilot caps good.
choke orifice in float bowls open
try foam air filters.
New throttle shaft seals.
Compression tested, valves, cam chain, timing checked.
Strong blue spark.
spray carb cleaner looking for intake leaks.
Diaphragm drop test done.
 
Again I'm inexperienced at this so bear with me. Iv got some popping in the left exhaust which also seems to be running hotter than the right judging by some discoloration at the header. Also seems to take a few trys to start. And I pulled my plugs after and they looked pretty dark. But that was also after playing with the mix screws for an hour. I was thinking I should get new plugs, run it and see what they look like.

To answer you questions
- yes I disassembled and cleaned
- the choke orifice I'm going to have to look up, I thought the choke mechanism was on the side retained by a 10mm nut
- I'm actually waiting for some uni filters to arrive
- throttle shaft seals is somthing I need to look into.
-compression/valves/cam chain were last checked mid summer. I guess I should check again
-spark is good
-air leaks seem possible how do you use carb cleaner to see air leaks?
-drop test was good
 
A side view of the front of the float bowl, the orifice (Y) is tiny, spray carb cleaner through from top and bottom. Fuel to choke circuit comes through here.
With engine running spray carb cleaner on throttle shaft ends and area tween carbs and head, any change in how engine is running points at leaks.
The shaft end at cable lever is most subject to wear and sealing problems.
check petcock vacuum line / petcock diaphragm, rubber cap on other side checked for cracks.
 

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Last edited:
Low fuel level in a carb can cause lean running, and it seems you're got that on the left side. It can also cause hard starting. Your mix screws probably don't need to be so far open since you've increased jet sizes. I'd put them somewhere in the 2.5 to 3 turns out range. They can have a big effect on plug color. But your black plugs could also be from cold starting with the choke. Using the choke blackens the plugs up right quick and it takes a pretty good run down the road (at least a few miles) to burn them clean again.
 
But your black plugs could also be from cold starting with the choke. Using the choke blackens the plugs up right quick and it takes a pretty good run down the road (at least a few miles) to burn them clean again.

I put new plugs in it ran it at idle for about 30min. Then rev'd it some, shut it off and looked at the plugs. Left does look a bit lean. Becuse I didn't actually take it out (just got some snow were I am) this isn't going to be a very true reading is it? Also I tried turning my mix screw in a bit (2 3/4) and that popping almost seemed to get worse. I shouldn't have said popping its really more Like a burp. I'll attach a video if you wanna listen.

Also shaft seals seem ok

I hear it distinctly at the 2 and 10 second marks

Thanks
 

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