Carb sealing & Octane

JTinFL

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Port Charlotte Fl
What are symptoms of the carb not being sealed when attached to intake manifold?I'm running a Grubee 66/80 and I think it runs ok,but being new at motorbikes I probably wouldn't know the differance.Differant subject,should I use low octane gas or higher octane?
 
89 octane... dont need anything higher.

Intake can leak in two places... basically on both ends. I would get a set of Allen screws and a carb o-ring from sick bikes. Use the allen screws in place of the stock studs... the carb o-ring goes in between the carb and intake tube. Tighten everything down very good.
 
symptoms of a leak are; four stroking at high rpm's, odd idle characteristics, and an excessively lean combustion evidenced by a white tipped spark plug instead of a nice tan. After long exposure, the excessively lean conditions can wreak havoc on your engine.

I would just make the improvements i recommended so you don't have to even worry about it. If you need help getting the stock studs out send me a pm and I will help you.
 
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symptoms of a leak are; four stroking at high rpm's, ................

No, a lean mix will not cause 4-stroking. That's a sign of a rich air/fuel mixture. The rest is right. Don't confuse the poor guy.

Further to this, an 'O' ring butted up against the end of the inlet tube will not necessarily ensure a good seal, although it certainly helps.
First ensure that the inlet/cylinder gasket is sealing properly, with or without allen-head screws.
Then spend 30 minutes doing this.
Now you can tune the carb with confidence. Each time you put it together it will be the same.

... Steve
 
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No, a lean mix will not cause 4-stroking. That's a sign of a rich air/fuel mixture. The rest is right. Don't confuse the poor guy.

Further to this, an 'O' ring butted up against the end of the inlet tube will not necessarily ensure a good seal, although it certainly helps.
First ensure that the inlet/cylinder gasket is sealing properly, with or without allen-head screws.
Then spend 30 minutes doing this.
Now you can tune the carb with confidence. Each time you put it together it will be the same.

... Steve

I saw that... its my next project. Very good job/idea.
 
At the chance of sounding ignorant,what's four stroking.Bear with me guys.

A 2-stroke engine '4-strokes' when the fuel/air mix is way too rich. The engine tends to fire every second revolution instead of every time.

See this thread. There's a link to a YouTube video that illustrates 4-stroking very well:-

NT Carb Tuning Basics

... Steve
 
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