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Help: Still popping when low boost or no boost

BigDog05

VIP Member
Joined
Apr 9, 2004
Messages
749
Location
Pittsburgh,Pa
I got the sticking slide fixed, set floats @ 17mm and cleaned all the jets etc.

Sled is great under boost. Above 7000RPM the thing pulls great.

At 10-25 MPH the sled pops, non stop. Taped the pitot jet closed and removed jet all together and no difference. I guess the pitot jet doesn't do much under no boost.

Add a small amt of choke and popping stops. Had 4 new plugs in and they all are starting to color just a little bit from adding choke I suspect.

At 1000ft elevation, approx 30F. 135 mains, pilot jet 2 turns off seat, stock needle setting.

Do I raise the needles, or try turning the pilot jets out to 2.5-3 turns?

Thanks :o|
 

Turning pilot jets? Arent those fuel screws? I turned mine to 2 1/4 from 3/4 and the low end is much cleaner in the garage. I am glad to hear you set your floats that low because I was worried about setting mine at 15 which is the max in the Service manual. Is it possible that at 17mm you could be running out of fuel or sucking air?
 
Freak, Thats what I meant: fuel screws. If I was sucking air or running out of fuel because of fuel bowels running out of fuel, wouldn't it get worse at higher RPM's?

From day one this thing has run great above 7000RPM. It has also popped
from the exhaust since day one, even when the float bowels were around 12mm from factory.

It always happens when I let it hang between 4500 and 6500-7000RPM.
If I accelerate thru that range, it does not pop at all.

Only when trying to go slow in that range. Spray 25 and some of the others seem to be having good results around 17mm. Thanks
 
If everything is sealed good , I would consider raising the needles to the next slot up and see what happens , this should richen it in the condition you are describing.
 
I kinda have the same trouble and I raised my needles one clip and it got a little better. I think I will do it again but I really think that richer midrange needles is the answer.
 
Freak said:
I kinda have the same trouble and I raised my needles one clip and it got a little better. I think I will do it again but I really think that richer midrange needles is the answer.

I don't think raising the needles will solve your problem. It will cause you to use more fuel. My needles are in the stock position. Mine runs poorly when cold at startup, but fine after a couple of minutes of warmup. The idle also increases once warm. It will barely idle when cold(first start of the day). This is new this year and I'm not sure if it has anything to do with switching from the Switzer to the Garrett turbo. I have set the screws to 2.5 and synched the carbs with no real improvement. I think raising your needles may only mask the real issue.
 
Buckeye said:
Freak said:
I kinda have the same trouble and I raised my needles one clip and it got a little better. I think I will do it again but I really think that richer midrange needles is the answer.

I don't think raising the needles will solve your problem. It will cause you to use more fuel. My needles are in the stock position. Mine runs poorly when cold at startup, but fine after a couple of minutes of warmup. The idle also increases once warm. It will barely idle when cold(first start of the day). This is new this year and I'm not sure if it has anything to do with switching from the Switzer to the Garrett turbo. I have set the screws to 2.5 and synched the carbs with no real improvement. I think raising your needles may only mask the real issue.

what kind of float level do you have yours at.
 
Buckeye, mine does exactly the same thing when first started from cold. It will not idle without playing with the choke.

Once I get it running I have to take the choke all the way off and in about 30 seconds I have to give it a little choke for about 20 seconds. I have to go thru this cycle 4-5 times. The only way it will run is to keep doing this or hold the gas open a little.

I have syycronized the carbs and they are right on, once sled is warm it seems to idle fine ,except I can not set the idle any higher than 1300-1400RPM. If I set it at anything over 1400 it will not idle down once throttle is applied.

I don't have any baseline to compare with because I brought the sled home from the dealer and took it apart to install turbo.

Thanks guys
 
Check your valve clearance,if the exhaust valve is held open at all it will do this.It's not hard to do_One of two things will happen soon,either a burned exhaust valve or worse a dorpped valve,if you don't eliminate an open valve.
 
BigDog that is exactly what happens with mine. If I up the idle at cold it will go up to 4000 once warm. I don't know the float levels, but I have never changed them and they were fine last year. I hope it isn't a valve issue. I don't think it is, because the mechanic checked everything when the engine was apart.
It is frustrating though to deal with this every time you start it cold.
 
Take those enrichners apart again and check everything in there, it sounds like one is leaking air, That happened to a couple of turbo people that i know of, my popping is only at full thottle and only at full speed and still havnt fixed it yet but still tryin, It would make sense that when put on the choke your moving the enrichner cuasing it to stop leaking
 
Thrusted Vector: If a valve was sticking open, would it show up at higher RPM when under boost?

This thing runs great once over 7000RPM. It just seems like once the boost gauge shows more than 3lbs it is smooth as can be.

And if I accelerate thru the 4500-7000 range it does not pop at all.It does not have to be hard acceleration. I just can't leave it hang under 7000.
 
Seems like this popping is a very common problem with RX1 turbos. Mine does the exact same thing, popping at low throttle settings. I have moved the needles, no results.

Mains 132.5
needle stock
15 pilot
floatbowl update
 
Big Dog- I may sound like a broken record here, but JET UP- it needs more fuel! I run 170's and my buds run anywhere from 150's to 180's (up to 17Lbs Boost)
 


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