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Old 03-12-2008, 07:51 PM   #1
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Default Jammin JPX .28

Hello, let me start by saying I tried a search and could not find anything about the problem I'm having. Maybe I don't know how to use the search function

The problem I'm having with my Jammin/Picco JPX .28 is the throttle is sticking open, which makes jumping really hard to do. It's sticking strong enough that the servo (Futaba S9452) and return spring don't pull it back in. If I tap the brakes it will go back in. Someone told me about removing the carb, then the idle screw and then the slide and polishing it??? This engine is new by the way, only about seven tanks on it after break in.

If anybody can help it is greatly appreciated.

Thanks.
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Old 03-12-2008, 09:06 PM   #2
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Quote:
Originally Posted by FG101C View Post
Hello, let me start by saying I tried a search and could not find anything about the problem I'm having. Maybe I don't know how to use the search function

The problem I'm having with my Jammin/Picco JPX .28 is the throttle is sticking open, which makes jumping really hard to do. It's sticking strong enough that the servo (Futaba S9452) and return spring don't pull it back in. If I tap the brakes it will go back in. Someone told me about removing the carb, then the idle screw and then the slide and polishing it??? This engine is new by the way, only about seven tanks on it after break in.

If anybody can help it is greatly appreciated.

Thanks.
Best bet is to contact OFNA, they will likely send you a brand new carb for it...

But you can fix it if you choose, usually the idle needle tip is too fat for the groove cut into the slide, which causes it to bind up... Using a rubber abrasive bit on the Dremel smooth down the tip of the idle needle... If that doesn't work then you need to use fine sandpaper and smooth down the slide barrel and the housing it slides in.... after sanding use a little toothpaste and lap the slide into the housing....
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Old 03-12-2008, 09:57 PM   #3
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Ok I will do that. Does the idle needle just unscrew all the way out? Seems like it is only binding when the engine is hot.

Thanks.
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Old 03-13-2008, 02:23 PM   #4
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if your return spring has an angle against the barrel that will cause the barrel to off set and dig into oneside, I use brace rubber bands for return and I only use 3 to 4 rubber bands to make the tension too much will cause the off set and will also dig into the barrel.
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Old 03-13-2008, 02:29 PM   #5
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a couple other things to check for is left over shavings from the machining process that can jam things up and also make sure the linkage isn't binding causing the slide to bind inside the body. Other than that OFNA should replace it for you if nothing else works.
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Old 03-13-2008, 05:57 PM   #6
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It looks like it's the return spring actually. Felt bindy with the servo disconnected, removed the return spring and it's free as it possibly could be. Will relocate it and see if it's still causing a bind.
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Old 03-13-2008, 09:33 PM   #7
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that still dosent solve the issue of when the carb takes heat soak and it locks up again....Its an Issue with the carb bold slide as Max already said....the return spring was only amplifying the problem.
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Old 03-23-2008, 01:13 AM   #8
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After much headache I figured out what the problem is. Picco carb's suck. When you get frustrated and pissed off, let the engine run up to 370 degrees, nice and fast.
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Old 03-23-2008, 07:00 AM   #9
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No The user sucks....as most would figure out the problem before doing something dumb like Purpously overheating the motor and ruining it completely...the carb issue is Simple to fix...Ur just making it out to be Way more then it is.
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Old 03-23-2008, 04:43 PM   #10
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Thats got to be it, if only I were as cool as some ricer. As far as I'm concerned purposely over heating the motor was'nt dumb. Could be why it done on purpose, driving around with a fart cannon is pretty dumb but done on purpose.
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Old 03-23-2008, 04:56 PM   #11
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no comment....do what u please.
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Old 03-23-2008, 05:37 PM   #12
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The Jammin/Picco.28 has had carb problems
since they came out. Yes they know about
the problems and no they haven't done a
thing about it. The .12 motor is a under powered
P.O.S. and everyone that I know that owns a .21
is always chasing a good tune. Thats why all the
top team drivers for Jammin, won't even think
about running a Jammin motor. I guess if you
were to put a Novarossi carb on that .28 you
might have something going on.
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Old 03-23-2008, 06:23 PM   #13
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Quote:
Originally Posted by rageworks View Post
The Jammin/Picco.28 has had carb problems
since they came out. Yes they know about
the problems and no they haven't done a
thing about it. The .12 motor is a under powered
P.O.S. and everyone that I know that owns a .21
is always chasing a good tune. Thats why all the
top team drivers for Jammin, won't even think
about running a Jammin motor. I guess if you
were to put a Novarossi carb on that .28 you
might have something going on.



umm..... Gary Guest AND Rick McCreary both run JPX's....and if ur buddy's are chasing a tune...its because of the carb leaking and causing high idling off jumps...thinkin its the low end but in reality its sucking air causing that run on....nothing with the motor itself...IMO when modded there isnt much that will touch a Picco.
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Old 03-23-2008, 07:15 PM   #14
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Quote:
Originally Posted by rageworks View Post
The Jammin/Picco.28 has had carb problems
since they came out. Yes they know about
the problems and no they haven't done a
thing about it. The .12 motor is a under powered
P.O.S. and everyone that I know that owns a .21
is always chasing a good tune. Thats why all the
top team drivers for Jammin, won't even think
about running a Jammin motor. I guess if you
were to put a Novarossi carb on that .28 you
might have something going on.
Sorry, I got to comment. I have seen three jammins on my track, one .21 and 2 .28's and none have had a problem. All seem to run great and one of the .28 drivers commented on good milage compared to the .21 he run before (He didn't say what the .21 was and i didn't ask)
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Old 03-23-2008, 08:29 PM   #15
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Picco does make good motors, as a matter of fact
I still own two Picco motors. Neither of which still
have a picco carb on them or the stock leakin arsed
front bearings. I bought these motors thinking that
the fact that they were about $100.00 cheaper than
some other motors that came out about the same time
would save me some money. But I ended up spending
the money that I thought I had saved just to get them
like they should have been out of the box. I have learned
my lesson the hard way and now I run much better motors,
that come with good carbs, bearings and will last twice as
long as the Picco's. Nuff Said
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