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Post by strangerdejavu on Jun 11, 2006 15:44:17 GMT -5
So here are the symptoms:
I ride my Primo Streaker 150 out to the airport a few times a week and have been noticing this occurance since about 100 miles on the odo. I take a back road with a 55mph limit, so it's full throttle all the way. About 4 miles down the road, the scooter begins to make this intermittent lag or dragging feeling.
How to describe it? Its as if you were riding full throttle, and every 10-20 seconds (sometimes more often) you VERY slightly pull the brake for half a second then release. How slight? When it happens, I can see no change on the speedometer or tachometer. The engine sounds the same (no noticable loss of revs or change of load). It's almost like something you sense as oppose to feel, but I swear it's there, and I don't think it's normal.
Another note is that, once the lagging starts, it doesn't go away with a reduction of speed. At the start of my ride, going 40 is smooth. I accelerate up to full speed (52 or so) and after a few miles the lagging begins. Then I decelerate to 40 again once I get to the airport and I can STILL feel it occuring; it's not smooth as it was before the engine warmed up, even though there's more available power.
Does anyone have any guesses to why this may be occuring? I'll tell you what I've tried thus far in a later post, but I want to hear any and all suggestions first. Thanks in advance for your help!
Jason
- on a side note, what kind of mileage are you guys with 150cc's getting when cruising full speed? Especially on Matrix-styled scooters?
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Post by 90GTVert on Jun 12, 2006 8:32:00 GMT -5
Just off hand, I'd say you have a minor case of fuel starvation or you're running too lean. Try adjusting the fuel mixture to richen it and make sure you don't have a line kink or vacuum leak. You may need to rejet, but probably only if you've replaced the air box. You may also need to set the float level a little higher, but try all the simple things first. Stan
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Post by Admin on Jun 12, 2006 12:21:17 GMT -5
That symptom is fairly common at WOT but should go away with slower speeds. I think Stan is right.
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Post by lewtwo on Jun 12, 2006 19:26:42 GMT -5
>> what kind of mileage are you guys with 150cc's getting when cruising full speed? <<
I can not comment on the Matrix, on my KeyWest ride I got 80 mpg there and back.
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Post by surfbum96818 on Jun 12, 2006 19:33:44 GMT -5
80 mpg was the norm for my SUN L pre catostrophic failure ( KIDDING ) also I want to ask about fuel lines But I think I will post a new thread about it after I make sure no one has asked the question before.
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Post by strangerdejavu on Jun 12, 2006 20:53:03 GMT -5
Thanks for the responses guys. I came to many of the same conclusions as Stan and did quite a bit of tinkering with the fuel mixture screw, so much in fact, that it fell out in the middle of a ride! Luckily it didn't fall out the bottom of the scooter! I haven't checked my spark plug in the past 50 miles, but last I looked it seemed fairly normal (as far as I could tell). I did a visual inspection of my fuel and vacuum lines last time I was in there tackling this problem and didn't see anything real obvious. Plus, since it doesn't seem to be a full-time problem, but comes on over time with WOT, I wouldn't expect that it's a kinked line. The float idea intreagues me, though. But what's the probability? I don't wanna go messin around in there unless I really have to!
Dawg, you say this is fairly common for WOT operations? Is it something I should just deal with? I'm mostly concerned about it tearing up the engine prematurely.
I'm also a bit curious when it comes to the mileage I'm getting. I'm finding that I get around 50mpg when I ride about 20 miles WOT. Keeping in mind that North Dakota is FLAT, but also offers some pretty stiff headwinds, I still expected a little better. I'm 6'3 and weigh in at 195, so I don't know if this is to be expected with the added wind resistance that is me. Any theories? I'm kinda holding out to see what kindof performance Aaron gets with his primo. We seem to be the primo pioneers around here!
Thank you all for your help!
Jason
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Post by 90GTVert on Jun 12, 2006 21:33:13 GMT -5
Does your scooter have a gravity feed system or a vacuum operated fuel pump? When it starts acting up, try loosening the fuel cap. You might have a plugged vent. I replaced my vacuum pump with a small electric fuel pump. I have no starvation problem, and later this week I'll be installing a 30mm carb. Don't underestimate how crappy the fuel filter, fuel and vacuum lines are on these! Stan
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Post by allengrota on Jun 12, 2006 23:54:13 GMT -5
Do the float as suggested, but also shorten the fuel and vaccum lines. Snip a little off both ends to make sure they aren't sucking air. Then replace the fuel filter or at least tie it in a vertical position. You can see how little fuel actually sits in it. It is easy to see how it could allow air into the carb as well. I think it is definetely a fuel starvation /detonation issue. Did you put in a brand name plug as well? The 50 mpg is a good indicator that it isn't really a float issue. That tells me you are most likely sucking air around the carb mount or hoses.
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Post by surfbum96818 on Jun 13, 2006 1:52:54 GMT -5
Allen if I could switch with you I would!!!! You sound like you know what you are talking about and I got to it by asking ALOT of questions !!!!
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Post by Admin on Jun 13, 2006 6:57:17 GMT -5
Surf, you are right about Allen. He has been my hero and top guru for a couple years. He's a genuine factory trained Geely mechanic, top notch BS artist and all around good guy.
Maybe I shouldn't have said that the hesitation is "normal". I'm thinking about my 80cc big bore scooter that does it at WOT. I seldom ride the 150's wide open. I'm betting that if you can find a larger fuel filter and check out Allen's and Stan's suggestions, you will be fine.
Also, we have some fuel issues we weren't dealing with before such as the way the fuel is formulated and the ethanol factor. I've been told....but don't know if it's true.....that you can't depend on plug reads like we used to. Ethanol may have it's place, but I don't think it's the best fuel for small engines.
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Post by strangerdejavu on Jun 13, 2006 19:27:22 GMT -5
Awesome, tons of good advice! Thank you! I tried the gas cap today, didn't appear to be the problem though. Good idea though! It hadn't occurred to me, and could have explained the problem. I'll be paying a visit to stan's website for some parts and give Allen's advice a try too. Y'all will hear from me again once I go through everything. Thanks again for the help!
Jason
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Post by Aaron on Jun 13, 2006 19:32:19 GMT -5
Jason have you run 100LL in it yet?
Aaron
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Post by strangerdejavu on Jun 13, 2006 19:37:15 GMT -5
Hahaha. No, I can't say as I have. I've been tempted, but that seems like an expensive habit to get into! I suppose I should give it a try though, just to see what happens!
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Post by 90GTVert on Jun 16, 2006 16:44:25 GMT -5
Have you checked to be certain you don't have a crack in your intake manifold? If you have one of the rubber coated OEM type, they tend to crack from the heat (Chinese rubber products generally suck). An easy way to check is to let the scooter warm up then slightly wiggle the carb (it'll flex a little but don't be rough with it) and listen for the engine idle to change. If it does, you have a leak. Also make sure your clamps and manifold nuts are tight while you're in there. Stan
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Post by strangerdejavu on Jun 16, 2006 17:16:43 GMT -5
Ooooh, good call. I'll make sure to give that a try. I plan to open 'er up this weekend and try all the above advice. Thanks Stan!
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Post by ooopseyesharted on Jun 18, 2006 9:57:54 GMT -5
my 50cc 4 stroke pooper does the same thing. Mine is definitely lean at the topend.
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Post by Admin on Jun 18, 2006 10:50:13 GMT -5
The fuel delivery system is designed for 50cc engine. After installing the 80cc kit, everyone I know has the same problem at WOT. I'm not sure which part of the fuel system is most restrictive but I'm guessing the small fuel filter. Also, the main jet size should be increased. The problem is so minimal that I don't worry about it.
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Post by ooopseyesharted on Jun 18, 2006 10:58:34 GMT -5
i replaced my fuel filter with a purolator filter and it made a huge difference.
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Post by Admin on Jun 18, 2006 11:01:45 GMT -5
There you go. My guess was good as gold.
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Post by ooopseyesharted on Jun 18, 2006 16:51:46 GMT -5
As always dawg.
As always
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