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Can bad reed valve cause lean or rich mixture?


the boris

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Just trying to figure out how can I have the same set up on both carburettors 30 pilots and 270 mains with one turn out on idle screw, needle 3 grove, and choke (left) side to be rich but right to be on lean side?

Now I just went to 290 mains wich should improve the right cylinder but that will also make left cylinder way to rich.

I spent some quality time on the carburetors, cleaning them and making sure nothing is blocked, I also changed choke o ring, which improved the "rich" situation but I'm not quite there yet.

The bike is sitting at 135-140 psi, it's got new set of pistons and jugs,has v force 3 reeds, fmf pipes, cool head with 21cc domes and K&N air filter.

I took it out for 5 min ride on Sunday, before i went to 290 mains,and the bike seemed to be going well but i didn't want to push it hard as I was not comfortable with main jet set up.

Don't know where to look at the moment.

 

 

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do a leak down and make sure you don't have a leak but...Not uncommon treat each cylinder like an individual motor .

you don't have to have the same jets in each carburetor. just monitor ,so if it was something stuck in the carburetor and it becomes unstuck it'll change (but more than likely, become rich, so shouldn't hurt)

Two other common problems are choke tube left out, slides in backwards and over oiled filters

Single air filter? If not swap those LtoR n see if it follows

 

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do a leak down and make sure you don't have a leak but...Not uncommon treat each cylinder like an individual motor .

you don't have to have the same jets in each carburetor. just monitor ,so if it was something stuck in the carburetor and it becomes unstuck it'll change (but more than likely, become rich, so shouldn't hurt)

Two other common problems are choke tube left out, slides in backwards and over oiled filters

Single air filter? If not swap those LtoR n see if it follows

 

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Mate thanks tor the advice, I'm in the process of making leak down tester so should have everything ready tomorrow.

This was my first time rebuilding banshee so i wasn't sure what is normal and what not,and since i changed couple of things in the rebuild from original set up (somewhat downgraded) wasn't sure if i had good starting point. Btw its single filter inside the box, no lid tho.

 

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You'll be 1/2 way to your reeds doing a leak down test. Might not hurt to look @ them too?

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I had a quick peak when i took my carbies off and one looks funky, I couldn't have a proper look but might take them off before I do the test. Should it be spot on closed or its ok to have a bit of a gap?

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Found this, quite interesting:

Durability isn’t the only advantage to different reed materials. A stronger, stiffer material allows the reed to be thinner and lighter. The lighter reciprocating mass of a reed increases performance. If the reed is too thin, however, it can start to flutter at high rpm. This means that the reed isn’t keeping up with the frequency of pulses of the engine and is disrupting airflow. Throughout its life span, a reed petal flexes millions of times, and its individual fibers start to lose their springiness. The reed’s modulus of elasticity decreases so that in equal engine conditions the reed will deform and open farther. This is called hang-open and affects performance. It can even make the bike run a little richer off the bottom.

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GF are great reeds that make the most power but require more petal changes. They’re thin. If your seeing light, change them up.

so you solved the richness in one cylinder after the o ring change or still rich?

carbs wear out and don’t respond to minor changes sometimes. I have a set like that.

Edited by gusto
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GF are great reeds that make the most power but require more petal changes. They’re thin. If your seeing light, change them up.
so you solved the richness in one cylinder after the o ring change or still rich?
carbs wear out and don’t respond to minor changes sometimes. I have a set like that.
It's definitely reed, only on the left side tho,the right is in superb condition. I had a decent engine damage on that side before the rebuild, probably damaged the reed too.

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