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Discussion Starter · #1 ·
first, why 2 jets, what do they do and when do they come on?
what does the needle valve do?
how much restriction should the air cleaners provide?, I installed foam and I can`t detect any restriction.
 

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The 175 have 3 jets ( but you can only replace 2) the jets work in overlapping spheres of influence with different throttle settings
Equally important are the needle and float Heights as well as the carbs being synced
The jets are all on all the time but are of different influence at different settings... The main jet for example is only influential at 3/4 - full throttle but is open from idle-wot
The filters aren't supposed to restrict air flow, they're there to provide laminar flow ( get rid of turbulence in the air flow) it's really important that the filters are the correct volume of air not that they restrict air
If thier purpose was to restrict flow the stock filters would be smaller or the bike would have smaller carb mouths images.jpg
 

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Discussion Starter · #3 ·
what should the clip position on the needle valve be? also the taper on the needle valve is different on the original then the ones that came in a rebuilt kit, is it better to use the original? what about the other brass parts?
 

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Threw the rebuild kit away and use the original brass parts. Go to your local Honda dealer and get new rubber parts from them, clean the parts and reassemble them.
TOOLS
 

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As tools states most aftermarket kits are just WORNG
the reason there are clip positions is so you can adjust the needle hight for your specific bike. When you're tuning that's when you need a box of sparkplugs to plug chop
Clip starts in the middle and goes up if the plugs are lean at 1/4-1/2 throttle or down if its rich
Are your exhaust and airfilters stock? You need to think holistically around the carbs

Do a hunt on HT for Steve's (aka 66Sprint's) carb set up. Follow it to the letter. Clean the carbs gently but to the point you could have it surgically implanted without risk of infection

Post a picture of your bike
 

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Discussion Starter · #7 ·
The 175 have 3 jets ( but you can only replace 2) the jets work in overlapping spheres of influence with different throttle settings
Equally important are the needle and float Heights as well as the carbs being synced
The jets are all on all the time but are of different influence at different settings... The main jet for example is only influential at 3/4 - full throttle but is open from idle-wot
The filters aren't supposed to restrict air flow, they're there to provide laminar flow ( get rid of turbulence in the air flow) it's really important that the filters are the correct volume of air not that they restrict air
If thier purpose was to restrict flow the stock filters would be smaller or the bike would have smaller carb mouths View attachment 263982
wow, nice graph , can you explain what it is tell us?
 

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It shows importance of each carb circuit/adjustment as throttle opening changes. So for example at WOT, it's showing that the main/air jet and the needle taper are important, and that the main air jet is more important. Another example is comparing one throttle opening to another, so comparing 3/4 to WOT, at 3/4 needle taper is quite important, main air jet not so much. Moving to WOT, main air jet is more important, needle taper not so much.

One thing I'm not 100% about is if the vertical scale is absolute (ie. meaning clip position is more important than everything else at 1/8 to 3/4).
 

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Discussion Starter · #10 ·
riddle me this, if I take the air cleaners off and put my hand against the mouth of the carb, I get fuel on my hand, where is the fuel coming from? and is this correct, because the engine revs up until I completely cover the mouth, then it dies.
 

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Fuel is coming from the fuel tank via petcock, fuel lines and carb bowl...same place the fuel going into the engine comes from
It gets spat backwards in the pressure wave that occurs when the valves close. If you had the correct air filter in place it would get sucked back in with the next intake
It gets stuck to your hand because you pulled the filter off and put your hand in the way.
Putting your hand in the way affects the mix as you're choking the engine ( stopping it breathing in oxygen)
As a life lesson.... Choke anything long enough and it will die.
 

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When you put your hand over the carb you are choking off all air into the carb. The engine wants to suck in air and the only opening it can suck anything in through is the pilot jet since that is the only thing in the carb open at idle and your hand is choking the airflow. Doing this is a good way to clear a slightly plugged pilot jet or check for a big vacuum leak. It is common for your hand to be covered with gas when doing this as you are flooding the intake with all the gas being sucked through the pilot jet.
TOOLS
 
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