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help with low speed needle settings.. engine acting weird

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help with low speed needle settings.. engine acting weird

Old 09-28-2003, 03:43 PM
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tofufar
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Default help with low speed needle settings.. engine acting weird

okay... so i got my HSN dialed in and the car was running fine. fast accel and didnt seem to bog in the transition between low speed and high speed. yet the low speed needle was still at its factory setting which i guess was at 3 1/2 turns out. it said that after breakin though it should be around 3-2 1/2 so i leaned it out. this is where it gets weird....

i turned the needle clockwise which i am sure leans the carb out but the low end started bogging... this seemed to be the opposite of what was supposed to happen. the engine wouldnt idle all that great and there would be a stutter in acceleration. It would go slow then suddenly RPMs would skyrocket and it would start giving off alot of smoke.

So i richened up my HSN a bit... turned the LSN back to factory setting then leaned out my HSN again... the transition seems good.... i dont know if its going at top speed though. The running temp is around 230-240 after some high speed passes and it makes a good zing sound. it doesnt seem to hesitate between high speed and low speed either. i have no way of clocking it though. if i lean out my HSN more... will i need to change the LSN again? I did the pinch test at first and after i changed the LSN from factory... it would die within like 1-2 seconds with no noticiable RPM boost. Af factory specs ,,,3 1/2 turns out... it would give a good RPM whirl then die after 3-4 seconds. this makes no sense... 3 1/2 turns is supposed to be factory and therefore rich... no??

my main question is... is my LSN too rich??? it was so weird... the more i richened it up, the faster it accelerated. leaning it out just made it sputter and gave me a bad transition. whats up with that??
Old 09-28-2003, 04:00 PM
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Billyman
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Default RE: help with low speed needle settings.. engine acting weird

The LSN has no effect on your top speed. It’s actually part of the idle circuitry and just a little beyond. Hence an incorrect setting giving a “bog” when accelerating but ONLY if the engine is at a very low RPM or idling.

If it’ll idle fine and the transition is good. Leave the LSN alone and work with your HSN.

As far as the factory settings are concerned, the instructions are a tool and starting point. Settings differ greatly at different elevations, humidity percentages and dew points within a particular area and even ambient temperatures.

Final tuning is in your hands.
Old 09-28-2003, 04:21 PM
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tofufar
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Default RE: help with low speed needle settings.. engine acting weird

hey there

thanks for the prompt reply. that makes alot of sense, everyone says the needle settings arnt an exact setting. it just struck me as weird how it was acting because it seemed backwards O_o

one last thing, i asked this in my first post but it was long and maybe you missed it. If i work on my HSN will my settings for my LSN need to change. Because i was thinking about it and yes... its transitioning fine now... but if i tweek the HSN and it goes faster.... a lag in transition may appear right? because id be moving the two powerbands father apart.... comments?
Old 09-28-2003, 06:54 PM
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Default RE: help with low speed needle settings.. engine acting weird

Actually, I didn’t miss it.

It’s very, very rare that one would have to re-adjust the LSN once it’s been set unless you changed elevations or sommat dramatically. In your case, you shouldn’t have to touch it again. Just adjust your HSN until you are satisfied with the engines performance. You really shouldn’t experience any new found lag if you don’t have any now just by adjusting you HSN.

Remember this:

Too fat causes a poor running, no RPM building engine.

Lean=mean but too lean causes a blown engine.

Find the happy medium with the HSN.
Old 09-28-2003, 09:20 PM
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rdandy5875
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Default RE: help with low speed needle settings.. engine acting weird

So if the LS is too rich it will bog right?
How can you tell if your LS is too lean? My buggy runs great, but the LS setting is like [X(] 2 turns leaner than the manual states and I don't wanna hurt anything.

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