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Post by Availien on Aug 30, 2015 9:47:15 GMT -5
after spending all this money on this 139qmb, we could buy a 150cc motor...something to think about...lol. I'm thinking about it honestly. $150 for a stroker crank...$150 for a quality transmission kit...$100 more, BAM! 150cc motor. True. But it wouldn't be nearly as fun. I'm into this as a hobby. It does frustrate me when things go wrong but not for long. I learn from it and keep moving forward. This has been the most educating scoot I've modified. This is number 5 for me and by far the most in depth. I used to just slap a BBK in and upjet and call it done. I'm going all in with this one. That stroker crank is freakin' awesome!! Totally worth it. Power gain from that simple part is ridiculous. You should try it out. It's not that hard to install. Took about 3 hours. I was going to document the entire thing but my phone was stolen so I didn't have a camera. I had to change my oil pump to make it work but it was very simple. Without the final drive gears, the scoot maxes out at 46 mph. It doesn't matter if the wind is against me or with me. She still gets there. And fast. I haven't compiled any data for acceleration time yet but I'm thinking it's around 8-9 seconds 0-30mph. Before doing any work to it, acceleration time from 0-30 was around 20-25 seconds. Very slow. Sluggish uphill and struggled to break 25mph against the slightest wind. Top speed was around 30mph give or take 2mph. My next project will most likely be a 2T. I wanna pop some wheelies. |
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Post by iwiketuddlz on Aug 30, 2015 20:12:32 GMT -5
Lol once you go 2t you will never look at a 4poke the same stroker or not just doesn't compare!!!!!
Braaaap. Braaaaaaap
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Post by Availien on Aug 30, 2015 21:53:08 GMT -5
I've owned both. I love how simple 2T is. And there is more bang for your buck when upgrading. I also love 4T though. They are very dependable and last a long time. I can take my scoot on a 200 mile trip and not have to worry about anything going wrong. That's almost on a bimonthly basis for me. 60 miles to visit my parents, 60 miles back, and around 80 miles playing around when I get there driving on trails and what not with my buddies in the country. I've popped a few belts but nothing major has ever went wrong. If I had a 2T, I would never take it on that long of a trip. But I do love how powerful 2T is. I would only really take the 2T to the drag strip to mess around or short trips around town.
Anyways, I guess what I'm saying is, both styles of engines have pro's and con's. I'm equally happy with either.
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Post by encephalon on Aug 30, 2015 23:58:52 GMT -5
what kind of problems are common with 2Ts?
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Post by spaz12 on Aug 31, 2015 0:07:56 GMT -5
what kind of problems are common with 2Ts? Broken belts from too much power  |
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Post by iwiketuddlz on Aug 31, 2015 15:23:33 GMT -5
Hehe yes sir I have demolished 2 in less than 1000miles!!! Lol darn EVO, but far as reliability I would trust my 2t over a 4t any day!!
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Post by ohhbuddy on Aug 31, 2015 16:31:52 GMT -5
what kind of problems are common with 2Ts? neck snapping acceleration |
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Post by Availien on Aug 31, 2015 22:37:58 GMT -5
what kind of problems are common with 2Ts? 2T engines have to be rebuilt more often. Especially if you give it hell. Here's an excerpt from a website: A Common List of Advantages and Disadvantages Advantages of 2 Stroke Engines: - Two-stroke engines do not have valves, simplifying their construction. - Two-stroke engines fire once every revolution (four-stroke engines fire once every other revolution). This gives two-stroke engines a significant power boost. - Two-stroke engines are lighter, and cost less to manufacture. - Two-stroke engines have the potential for about twice the power in the same size because there are twice as many power strokes per revolution. Disadvantages of 2 Stroke Engines: - Two-stroke engines don't live as long as four-stroke engines. The lack of a dedicated lubrication system means that the parts of a two-stroke engine wear-out faster. Two-stroke engines require a mix of oil in with the gas to lubricate the crankshaft, connecting rod and cylinder walls. - Two-stroke oil can be expensive. Mixing ratio is about 4 ounces per gallon of gas: burning about a gallon of oil every 1,000 miles. - Two-stroke engines do not use fuel efficiently, yielding fewer miles per gallon. - Two-stroke engines produce more pollution. From: -- The combustion of the oil in the gas. The oil makes all two-stroke engines smoky to some extent, and a badly worn two-stroke engine can emit more oily smoke. -- Each time a new mix of air/fuel is loaded into the combustion chamber, part of it leaks out through the exhaust port. Citation: www.deepscience.com/articles/engines.html |
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Post by spaz12 on Sept 1, 2015 14:37:44 GMT -5
 - Two-stroke engines have the potential for about twice the power in the same size because there are twice as many power strokes per revolution. I don't mind changing rings or a top end every once in a while.
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Post by Availien on Sept 3, 2015 12:10:18 GMT -5
So I finally worked up the courage to open my scoot up full throttle for an extended period of time. Not cool. I think I may be having some detonation issues. Not entirely sure. I'm running 93 octane. 50mm piston, 44mm stroke, ~87cc displacement, #107.5 mikuni MJ. Open style air filter. Reversed my advanced timing modification to the pickup. Still happening.
Symptoms. At WOT near 8k RPM I hear some popping coming from the muffler and then it bogs down for a quick second like it's not getting fire at all (like if I were to hit the kill switch momentarily) and then picks back up and repeats it. Not sure what the hell is going on but I don't like it. Hopefully it's not detonation. I need to check compression.
Any thoughts would be most welcome.
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Post by Availien on Sept 3, 2015 12:12:08 GMT -5
I just remembered I replaced the No Rev limit CDI with the stock one a while ago. I'll swap them out again and see if it still happens.
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Post by Availien on Sept 3, 2015 22:24:22 GMT -5
Not the CDI.Swapped em out. Same thing. I think I may just be a little too rich. Stopped at a light tonight and when I went to open the throttle it just cut off. Not once. Not twice.... Three lights. So annoying.
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Post by 90GTVert on Sept 4, 2015 7:43:11 GMT -5
Detonation doesn't usually make the exhaust pop or backfire. Most of the time with these 4Ts it will sound sorta like someone put marbles in the combustion chamber when it happens.
You may have a carb tuning issue. Checking the plug should give you more insight.
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Post by Availien on Sept 7, 2015 8:24:43 GMT -5
Detonation doesn't usually make the exhaust pop or backfire. Most of the time with these 4Ts it will sound sorta like someone put marbles in the combustion chamber when it happens. You may have a carb tuning issue. Checking the plug should give you more insight. I was running rich. Moved down to a #100mj. Problem ceased immediately. Thanks Brent. |
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Post by Lucass2T on Sept 7, 2015 16:57:50 GMT -5
Did i tell you i did 600 miles in 5 days with my 70cc 70mph aircooled daily driver in hot French 85 degrees weather? With some engine mods and all and that it didn;t break down ONCE?
Oh and that i have 250 mile trip in store coming weekend? With the 70mph daily?
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