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Tuning troubles. Air bubbles?

Tuning troubles. Air bubbles?

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Old 08-07-2014, 05:18 PM
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Default Tuning troubles. Air bubbles?

Hey guys, what could be a cause for air bubbles in my fuel line? My main problem is ic cant ant seem to perfectly tune my nova flash .12. One min the engine bogs down and has to clear out when acceletating before it actually picks up speed normal. Or it acts like it is wayyy to lean . these are the problems at th idle. It's never consistent. I started noticing these problems once I got to about the 6th tAnk in break in. Once I would try to bring it to high rpms
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Old 08-07-2014, 09:14 PM
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the only things for air bubles would be a bad line or tank my keep-on was a B**ch as well had to replace the front bearing, seal the carb, and backing plate, and had to spin the heck out of the screws but i finally think i have it mine was the bottom was way rich and the idlescrew way to open and the top way lean run great for about half a tank and change over run with poor drivability run good refuel at pit stop and could not get out of own way it was poor to say the least
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Old 08-08-2014, 12:09 PM
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Question, The air bubble a big one, or is it small bubbles like fish eggs? Watch it while on your test bench, with wheels off the ground. Are you pumping blue smoke? Maybe just to rich. Seal the fuel line from Tank to the carb with ATV sealant just a start, and keep the fuel line as short as possible.
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Old 08-08-2014, 01:03 PM
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You have posted this same Q in a few forums and have gotten same answers ..REPLACE ALL FUEL LINES ALONG WITH TANK O RING.
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Old 08-08-2014, 05:01 PM
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Originally Posted by illmatic94 View Post
Hey guys, what could be a cause for air bubbles in my fuel line? My main problem is ic cant ant seem to perfectly tune my nova flash .12. One min the engine bogs down and has to clear out when acceletating before it actually picks up speed normal. Or it acts like it is wayyy to lean . these are the problems at th idle. It's never consistent. I started noticing these problems once I got to about the 6th tAnk in break in. Once I would try to bring it to high rpms
People have been telling me lately that novarossi engines like to be around 300*. I know it sounds crazy, but it's true. I very rarely use a temp gun to tune my motor, unless I'm having a hard time. As long as it's blowing smoke and has the speed I'm comfortable with I leave it.
It says you're from NY, what part? If anywhere near Floyd there's plenty of good people there that'll give you a hand
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Old 08-08-2014, 05:38 PM
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I have not been to a lot of big on road races. One of the only touring car "pros" I have ever seen is Paolo Morganti this year when he came to the Novarossi Challenge in Houston. He was either running a Keep On or Virtus 0.12. When he got up to race temperature his car definitely had a high idle, much higher than what I am used to in off road. It had that "lean sound" at idle. I myself have had only one touring car engine, a Novarossi 353 that I bought last year from DeSoto. If I tune it so that it idles down immediately when it is hot, it does not make nearly enough power. However, if I can live with the high, "lean" sounding idle, it is a rocket. I suppose it becomes a problem only if it is high enough to engage the clutch and interfere with braking. The high idle doesn't seem to hurt fuel mileage.

I talked to DeSoto himself at the offroad nationals and he said that this is normal for the Novarossi 0.12 carburetors. He says that the high idle is OK and you should tune it so that it settles back down, not immediately, but after several seconds completely off throttle. He said that this phenomenon is more of an issue with Novarossi carburetors with a metal body and neck. He said that older carbs with a plastic neck will idle down more easily.


I personally have found it much more difficult to tune these engines than anything else I have dealt with before in Off road.
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