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Discussion Starter · #1 ·
Hi all,
I'm getting my ass handed to me on my daughter's bike.

Bike starts and idles great, but rough as a cob when I open the throttle.

TPS checks good

Carbs have been cleaned thoroughly. Several times. Stock jets. Float levels correct. No intake leaks. Good compression.

Valve timing makes me wonder, as the lines seem a couple of degrees off, but there's no adjustment for valve timing, as far as I can tell. (tensioners are good).

If I cover the oval ports (adjacent the main body inlet) with tape, it runs better, but not good.

This started as an intermittent problem, but now constant.

ANY pointers appreciated.

Thanks so much,

Chris
 

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Discussion Starter · #3 ·
Restricting the air inlet doesn't improve things; it's only when restricting the small arc-shaped ports (about 1/4" x 3/4") that helps, and that still only helps some.
Jetting is original. Floats are set correctly. leak-checked the boots - no leaks.
Plugs get wet (rich)
 

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Administrator "Loose Nut" - from Houston, Texas
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Then it appears you have a fuel delivery issue. I understand you have cleaned and double check everything, but facts strongly suggest fuel issue. I would take a look at chapter 8 starting on page 320 of repair manual for a nice trouble shooting guide.


Blue Font Screenshot Parallel Number
 

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Discussion Starter · #7 ·
I will read through again carefully, and sincerely appreciate your input.
I have replaced the fuel pump. I don't have the air box installed. I've cleaned the jets multiple times.
I'll check float level again. Diaphragms look good.
Thanks for the link; not the same manual I have, so I'll search for differences.
 

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Administrator "Loose Nut" - from Houston, Texas
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It's hard, almost impossible to diagnose a fuel issue without air box attached. Carbs operate on a venture effect to suck fuel from bowl. The fuel metering is messed up without air box on. I would attach air box to get a real feeling on what the fuel flow is like.
 
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