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Post by sevenninesandtens on Jan 3, 2020 13:37:56 GMT -5
Hi everyone, long time lurker first time poster. I have a 2005 Vino 2t. When I got it a few months ago the engine kept flooding and it wouldn't run. I liked the idea of tinkering and bringing it back to life. Couldn't get it to stop flooding so I replaced a lot of things, while I was at it I upgraded as well. So now I have the following:
Polini Sport 70cc
Polini Speed Exhaust Polini 17.5mm Carb (Stock jets of 38 for the pilot and 80 Main)
Polini Air Speed front pulley Polini Hi Speed Variator Polini 3g Clutch 105mm Polini 48mm 90º Short Air Filter
When I first started her up the idle shot straight up to 9500 RPM. So I ordered pilot jets and I have a 52 in there now. Problem is it's still running lean with the idle rpm's not sitting still. I can get them to calm down somewhat but as soon as I give it gas the rpm's start to run away from me up to about 2600-2800 rpm. I've been searching for solutions but everything I've tried hasn't helped. I live in Philadelphia, Pa at about 235ft above sea level. I haven't found pilot jets that are larger for the Polini. Is there another brand that I can use that would work? I tried covering the air filter holes with tape and that didn't help (no change at all really). Was thinking about going back to the stock airbox without the snorkel but to do that I'd need to find an adapter since the Polini has a much larger connection than the stock one. Any suggestions before I try the old airbox? And if I do need to go back to the stock air box could I just attach some kind of new hose to make it fit? If so what would I use?
No restrictions are left on the scooter. The exhaust pipe does seem to have a small leak where it meets the cylinder head, as it looks "wet" there. Not sure if that would be causing this issue though.
Any help would be appreciated! Mike
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Post by laz231 on Jan 3, 2020 15:37:55 GMT -5
you must have an air leak try covering the carb see if it stalls and check for vacum leaks
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Rune 75
Scoot Enthusiast
Posts: 441
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Post by Rune 75 on Jan 3, 2020 16:05:43 GMT -5
Have you tried slackening the throttle cable?
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Post by lilpinny on Jan 3, 2020 16:35:34 GMT -5
If it's hunting RPMs, going up and down, you got an airleak.
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Post by Happypancake! on Jan 3, 2020 16:52:34 GMT -5
If it's hunting RPMs, going up and down, you got an airleak. Use a propane torch to find a leak. (don't light it)
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Post by oldgeek on Jan 3, 2020 19:18:34 GMT -5
I think you are on the right track going back to the stock air box. With your setup there is nothing to gain from a "performance" air filter. The stock air box will greatly ease your tuning woes. And yes, you can connect it using any means necessary, as long as there are no leaks in your connections. 2T's require stable airflow. The Vinos are nice scooters, light and quick. I had one that would take me to 55 with just a well tuned 70cc sport cylinder and a pipe, and I am a heavy guy.
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Post by Zino on Jan 4, 2020 8:28:54 GMT -5
You have a air leak You will not be able to fix with jetting and air leaks tend to get worse with time .
Use a unlit propane torch some use starter fluid . With the scooter running . Follow the seams around the cylinder head and base gasket around the carb intake and the reed valve . When the idle changes speed that is where you air leak is . These are the easiest ones to check the next 2 are more work .
There are 2 other places that leak the crankshaft seals one is behind the variator the other is behind the fan on the other side.
You also can make a leakdown tester and chase down the leak with soapy water.
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Post by lilpinny on Jan 4, 2020 8:46:05 GMT -5
Or ask a friend that vapes to blow a big cloud down there to see where it goes.
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Post by repherence2 on Jan 7, 2020 20:50:26 GMT -5
Polini makes a carb airbox adapter. I bought one with my polini cp 24 carb. It adapted my stock airbox to the polini cp 24 carb mouth.
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Post by repherence2 on Jan 7, 2020 20:54:07 GMT -5
With a 52 pilot jet, how many turns out is your air screw?
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Post by sevenninesandtens on Jan 13, 2020 15:56:17 GMT -5
With a 52 pilot jet, how many turns out is your air screw? 2 turns.
Going to try the suggestions everyone gave and see what I get. May just go back to the stock carb and airbox we'll see. I was going to order that adapter but haven't found it in stock anywhere yet. That was my first option honestly.
Sorry for the delay, 2 kids means I don't have much time for myself!
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Post by sevenninesandtens on Jan 13, 2020 15:57:31 GMT -5
Or ask a friend that vapes to blow a big cloud down there to see where it goes. I could do that myself but the scooter may get a bit of a contact high
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Post by repherence2 on Jan 13, 2020 20:11:49 GMT -5
Or ask a friend that vapes to blow a big cloud down there to see where it goes. I could do that myself but the scooter may get a bit of a contact high 420 lol
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Post by sevenninesandtens on Feb 8, 2020 18:34:47 GMT -5
Ok so I finally had some time to take a look and do some testing. I ordered new gaskets and a new intake manifold thingy (the part that goes over the reed valves). There were some cracks in the intake so I just replaced that. Used a propane torch looking for leaks and found none around the carb and intake and such.
The spark plug is wet, very wet. black tar looking stuff. That is also on the exhaust pipe up by the cylinder. So I'm thinking that's where the problem may be. So I took off the pipe and took apart the cylinder. The face of that is also pretty black. Another thing I found is the piston rings spin freely around the piston. Are they not supposed to do that? Oh also when I took off the cylinder head the one long bolt that goes all the way through to the case came out when I unscrewed the nut. It was the one that is where the black tar leak was at.
Sigh. It's def a LABOR of like right now. Even with the new intake and the air screw turned all the way in it still runs for a while before it stalls out. So air is definitely getting in there somehow. I wanna take care of the cylinder leak before I try seeing if the crank seals are leaking. One thing at a time so they say!
What should I do about the cylinder? Get a new piston? Throw it all in the trash and ride a lawn mower?
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Post by 2stroked on Feb 9, 2020 8:54:36 GMT -5
sevenninesandtens When you say a "tar leak" was there a drippy black substance leaking outside of the cylinder? If so that's a problem. It could be that the stud wasn't seated into the block enough, and caused an air leak at that corner. The rings should move somewhat freely, but there is usually pins in the ring lands to clock the rings. They get clocked so the ring gaps do not line up with each other, allowing a compression leak. I'd try to clean things up, reassemble, and do a compression test. Then a leak down test. If you do t have a leak tester, there are quite a few different ways to build one all listed here on the forum. Brent, 90GTVert, has many videos which show you how to use one as well. Any tiny air leak, even an exhaust gasket leak, can wreak havoc with a two stroke engine. They are "simple" engines, with complicated taste.... The only thing simple about these engines is their construction. The operation is convoluted in that the tiniest thing off, will cause hell, or can possibly cause your cylinder to eat itself. Check the bore for any gouges, scratches, or marks that your finger nail can feel. Use new circlips to put things back together. A $.79 piece can cause your $300 top end to turn into a paper weight, stupid fast.....
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