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Post by xyshannen on Aug 20, 2014 16:08:41 GMT -5
Hi, New member here. Thank you all for such a wonderful site.
Now for my issue. I have a 20008 150cc Lance vintage with a gy6 short case clone. Today wile driving it @ 45 mph for 5 minutes it started sputtering like it was cutting in an out. I slowed down on the side of the road and it ran fine at 30 mph for a couple of minutes then I was able to continue cruising at 45 with no problems for a few minutes. But anytime I ran it for more than 5 minutes at that speed it would start to do the same thing. Now last nite I took her out and was able to cruise at 50 for as long as I pleased with no problems.
Here is what I'm thinking, It's flipping hot today here in JAcksonville FL, 110 on the pavement easy. I'm thinking that the gas is boiling in the carb after running it that hard in this heat. I totally could be wrong hence why I'm posting here looking for other ideas. So any help from the experts would be greatly appreciated.
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Post by pmatulew on Aug 20, 2014 17:25:00 GMT -5
Fuel pump, vacuum to fuel pump, and heat.
They don't like to run wide open. The vacuum is weakest there and the fuel pump is marginal to begin with,. Double check all of your vacuum lines. Consider replacing the pump. Also consider remounting the pump lower and closer to the fuel tank if it isn't already.
Heat is also an issue. Ambient temperature, working hard, plus running lean from the fuel pump.
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Post by JerryScript on Aug 21, 2014 0:11:17 GMT -5
One other thing to consider is your coil. If it's mounted near the front of the engine, as they often are on a GY6, it may not be getting much air flow around it at that speed, and overheating causing you spark issues during long WOTs. At one speed, it may get plenty of air flow in there, but at another speed it may develop an air flow bubble, holding the heat from the engine. While checking out your fuel situation, try moving the coil mount up and back as far as you can on the frame, getting it out of any possible front "bubble" situation.
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Post by xyshannen on Aug 21, 2014 8:59:05 GMT -5
Thank you both for your replies, you've given me at least something to look at.
Again last night on my way home it ran just fine. So heat is a def issue.
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Post by rcq92130 on Aug 21, 2014 14:00:51 GMT -5
Had something similar a few days ago --- culprit seems to have been the AutoZone fuel filter. Replaced it with a slightly larger from from elsewhere and the problem has not again happened.
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Post by xyshannen on Aug 22, 2014 13:23:32 GMT -5
I forgot to mention, I originally had plans to install a new muffler next month as the original one was rusted out. I also was not going to drive this scoot until said muf was installed. So I cut the original one off. Then due to circumstances beyond my control I was forced to put this scoot on the road with an open header. So now reading the boards I realize that I am running lean and overheating at these speeds. So until I can do something about it, (install bigger jets and a new exhaust system) on the first of next month, I will no longer be driving at those speeds in this heat.
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Post by JerryScript on Aug 22, 2014 23:37:46 GMT -5
You really shouldn't ride the scooter at all without at least an exhaust header on. You stand a very good chance of burning your exhaust valve up, no matter what speeds you try to keep it under.
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Post by xyshannen on Aug 23, 2014 20:09:45 GMT -5
There is a header, I cut it right at the muffler. I know riding open header is bad enough, I wouldn't ride with at least a header.
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Post by xyshannen on Aug 23, 2014 20:13:01 GMT -5
Sorry for the double post, stupid iPad won't let me edit...
What surprised me was that it ran just fine at night but in the heat of the day it ran lean after 5 minutes of cruising at 45 mph, (not WOT).
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Post by alleyoop on Aug 23, 2014 20:34:06 GMT -5
It is going to cost you more than a muffler
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Post by JerryScript on Aug 23, 2014 20:37:14 GMT -5
You are most likely burning up that valve right now.
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Post by xyshannen on Aug 24, 2014 14:10:22 GMT -5
Well crap! Eh, so be it. I'm planning on replacing the whole engine anyways. I really don't have a choice but to drive it. You see I do dialysis 3 times a week and like I said circumstances beyond my control, this is my only ride to and from the clinic. The good news is the clinic is only 3 miles away and I can keep my speeds to 30 mph.
Do any of you know what engine # is in this thing? I've search google and can't seem to find it and don't see it anywhere on the bike. I do know its a short case gy6 and that's about it.
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Post by JerryScript on Aug 24, 2014 22:10:41 GMT -5
Look on the left side of the engine block under the front end of the CVT. It should be stamped there, might have to clean off road grime.
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Post by seamus26 on Aug 25, 2014 9:17:04 GMT -5
Well crap! Eh, so be it. I'm planning on replacing the whole engine anyways. I really don't have a choice but to drive it. You see I do dialysis 3 times a week and like I said circumstances beyond my control, this is my only ride to and from the clinic. The good news is the clinic is only 3 miles away and I can keep my speeds to 30 mph. Do any of you know what engine # is in this thing? I've search google and can't seem to find it and don't see it anywhere on the bike. I do know its a short case gy6 and that's about it. Most likely 157QMJ. Check this info out : LINK
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Post by oldchopperguy on Aug 25, 2014 13:11:53 GMT -5
Xyshannen,
If you have a full header, just no muffler, you may or may not damage a valve. I believe it depends a lot, on just how hot your engine is when you shut it off (as well as just how good the quality of valve and seat is). Chinese quality varies a lot. We used to run fairly short straight-pipes on Harley drag-bikes, and only rarely did we damage a valve, BUT it did happen once in a while, ESPECIALLY if the bike was shut down right after a race.
I realize that you need to ride the scooter for health-issues, so you're fairly "stuck" with having to use it. I think that if you get the motor down to "normal" running temp after a high-speed run, before shutting down, you have a fair chance of "getting away with it"... LOL! But Alleyoop is right. The possibility of damage IS definitely there.
If you could simply clamp a foot or two of additional straight pipe (conduit, aluminum, whatever you can find) temporarily onto the stub-header, it should greatly increase your chance of preventing damage (and quiet it down some)... LOL! Just put it on with some muffler seal, and a wire hanger until you can fix it better. Just a thought, but a whole LOT of riders use long straight-pipes with seemingly no valve damage... They just like the sound. The engines DO need a little backpressure though to really run right.
All my best wishes on your scooter, AND your health!
Leo in Texas
PS: Even with a short, cut-off header, you should support the rear-end of the pipe... Even a wire hanger. Any weight hanging off the head is hard on the head where the pipe bolts on. You don't want to stress the head with any exhaust just hanging off the two studs. A little "bailing wire" can do wonders!
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..BAD TO THE BONE..
