Why does it run great only without filter?

Barry (Bob) Brown /
bbrownx
May 26, 2019 11:45PM

Hobbit, stock PA50II carb/intake - In trying to tune, I down jetted from 90 to 86, which helped but it still 4strokes a bit till it gets hot after few miles. I thought i'd look at the filter box but it looked ok. I dont have the snorkel in cause its a PA50I, but I took it for a ride without the filter box and it ran awesome, great power and hit 45 immediately? I took some pantyhose and threw it over the carb intake to avoid sucking anything into it as a test and it runs great - what do you think is going on?

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Re: Why does it run great only without filter?

Totally normal JBOT /
capturedbyrobots
May 27, 2019 12:07AM

Too rich or clogged filter

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Re: Why does it run great only without filter?

Thomas TPRF /
thomashsb
May 27, 2019 12:08AM

Down jet more?

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Re: Why does it run great only without filter?

pat splat /
ggspeed
May 27, 2019 12:41PM

45 on a pa50I, uggggh..... bs.

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Re: Why does it run great only without filter?

Beach Club Nick /
khool1499
May 27, 2019 01:30PM

> pat splat Wrote:

> -------------------------------------------------------

> 45 on a pa50I, uggggh..... bs.

It's a kitted pa50I with a pa50ii intake, TJT, new bearings and seals. It's not BS, it's just barely a pa50I now haha

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Re: Why does it run great only without filter?

pat splat /
ggspeed
May 28, 2019 01:51PM

i see, check that your choke aint hung up on your wires fuel line

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Re: Why does it run great only without filter?

Mike Boyd /
boyd
May 28, 2019 02:02PM

I tend to ditch the stock 40 year old dense ass rotting foam and cut a piece of uni foam for the filter box, oil it and viola

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Re: Why does it run great only without filter?

alex ganz /
zixor
May 28, 2019 11:47PM

Needs to be cleaned and made less restrictive. Insufficient air flow is hindering the pressure drop, thus intake of the carb. Down jetting likely allowed you to suck proportionally limited mix with the limited air, and allowed for combustion; I wouldn't run that for too too long. With the right amount of air, you may be a touch lean.

But this happens; little soap and elbow grease on the filter, add some new oil after - good to go. Or just get new foam. Either way.

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