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Post by jbbrack03 on Jul 14, 2011 19:57:08 GMT -5
Just joined the forum and you guys seem to know your stuff. I'm not a mechanic, but I'm willing to try anything as long as I have a good tutorial. I've been pretty successful so far.
I just traded someone and received a 2008 Velocity 150cc Scooter (ZN150T-7C). The scooter starts right away and it appears to be in good shape. The previous owner had it parked in his garage for about a year without any fuel in it. Right now it will only reach about 4000 RPM and 25 MPH. I'm a bigger guy (230 pounds) and I realize that a person's weight can affect the top speed of a Scooter. But I hope that I wouldn't lose half my potential speed as a result of my size. The scooter is supposed to have a top end of 50-60 MPH.
I pulled the Carburetor and took it apart. I cleaned out all the jets with Carb Cleaner spray and compressed air. I didn't notice any gunk coming out of it. This didn't help my speed problem. It does seem to bog down a bit when you open the throttle all the way. The air filter is brand new. That's the only thing that's been replaced that I'm aware of. I tested the Battery and it's fully charged and has a good core. I haven't changed the oil yet (need a bigger socket).
What should I try next to figure out this speed issue? Please talk stupid to me because I'm not familiar with all the terminology yet. I'm a very experienced Computer Tech and I'm not afraid to take something apart and put it back together. I'm good with tools, just not very knowledgeable about mechanical stuff.
EDIT: I just tried running it on the kick stand without being on the bike, and it still only reaches 4k RPM's. Just to prove that the issue at hand is not related to my weight. It's idling at around 1100 RPM.
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Post by 2wheelxtreme on Jul 14, 2011 20:57:38 GMT -5
hey man umm im not an expert on scooters but i do have some knowledge of trial and error so try to to ake the fuel line off and filter check for gunk in that or any leaks and so on. I would aslo check the oil has it been changed? might have to do with the clutch not engaging properly. I would also check the ntake for air leaks as well as the spark plug for discoloration(blackness). If black change that out. One other thing maybe possibly to check the air to fuel ratio screw on the bottom right or left of the carb depending upon what model carb it is and tinker with that and the carb idle screw too which is located on the top of the carb. some
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Post by mechaniczman on Jul 14, 2011 21:12:35 GMT -5
Yes a 150cc should deffinently be reaching 50mph and well over 4k rpms. You said you cleaned out the carb and it has a new air filter. What kind of air filter? Is it a performance one that eliminates the airbox or is it the stock airbox and just a new filter. If its a performance air filter you will have to up-jet the carburetor.
I would adjust your valves. How many miles are on the scooter? Make sure your throttle cable is opening up all the way.
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Post by 2wheelxtreme on Jul 14, 2011 21:17:48 GMT -5
yea i agree with mechanic wasnt exactly sure but i agree check your valves also check your vacum hose for leaks and make sure that and your intake hose are properly lined up with the carb notch to make sure its on strait and tight.
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Post by jbbrack03 on Jul 14, 2011 21:35:25 GMT -5
The Scooter has 500 Miles on it. Does my Model have a GY6 engine? How do I find out what model the Carburetor is? It's got the stock Airbox with a stock replacement filter. I was thinking about upgrading to a higher performance filter, but wasn't sure what to pick out. People were talking about K&N, so I was considering that. So you're saying that I can get an Air Filter that is used without an airbox? So I would remove the Airbox completely and somehow attach just an Air Filter? How would I go about seeing that my throttle cable is opening all the way? Remember that I am super new to this, so some steps would be helpful. What would I need to do to adjust the valves?
Thanks for all of the quick suggestions. I'm about to change the oil right now. Just went out and got some new sockets and gear oil.
I just took it down the road to walmart and I can provide a few more details. When it gest to around 4K RPM's and around 27 MPH it stops accelerating and I hear a rumbling low popping from around the exhaust area. I'm not sure if the sound is coming from the exhaust itself, and it's more of a growl coming from down there. Like a series of very light backfires. I don't think that it's actually backfiring, but that's kind of what it sounds like.
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Post by 2wheelxtreme on Jul 14, 2011 21:39:17 GMT -5
not sure about the valves sorry havent had an experience with those as of yet but with the air filter just remove the stock one with the hose and all attached and slip the new one lined up ith the notches on the carb to the carb itselfand tighten it up. Yes 99% sure it does have a gy6 engine as it is all honda made like my 150cc Q link pegasus its not honda but the engine is same with the velocitys as well.
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Post by 2wheelxtreme on Jul 14, 2011 21:41:14 GMT -5
Sorry just read about the walmart ride ummm still sounds the same could be a vacum leak coming from the vacum hose not 100% sure as i am not there to inspect it myslef
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Post by jbbrack03 on Jul 14, 2011 21:44:29 GMT -5
Ok. How would I check for a vaccum leak?
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Post by 2wheelxtreme on Jul 14, 2011 21:49:06 GMT -5
hope this illustration helps, and to check it look for tiny cuts or places on the rubber tubs where air could escape out similair to checking a bicycle innertube for leaks. Attachments:
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Post by 2wheelxtreme on Jul 14, 2011 21:50:54 GMT -5
if all seems okay there with all the connections and hoses, no leaks etc. i would proceed with changing the oil and gear oil.
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Post by Premier Scooters on Jul 14, 2011 21:52:04 GMT -5
It sounds like you might have a broken outer valve spring. Pull the valve cover off and check your valves gaps, it is a good idea to do that anyway. while you are in there take a flashlight and carefully examine the valve springs. The symptoms you are describing sounds like that. On a 150 with a broken valve spring it will usually top out around 25-35 and when you get near there it will start making a weird backfiring type of noise. I've seen it a few times.
Before you start doing performance modifications like a air filter it is a good idea to get it running right in stock form.
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Post by jbbrack03 on Jul 14, 2011 22:01:09 GMT -5
It sounds like you might have a broken outer valve spring. Pull the valve cover off and check your valves gaps, it is a good idea to do that anyway. while you are in there take a flashlight and carefully examine the valve springs. The symptoms you are describing sounds like that. On a 150 with a broken valve spring it will usually top out around 25-35 and when you get near there it will start making a weird backfiring type of noise. I've seen it a few times. Before you start doing performance modifications like a air filter it is a good idea to get it running right in stock form. Thank you for the response! Can you give me an idea of what to look for exactly so that I can check on what you suggested? If there is something wrong, what should I do to repair it? |
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Post by jbbrack03 on Jul 14, 2011 22:02:24 GMT -5
hope this illustration helps, and to check it look for tiny cuts or places on the rubber tubs where air could escape out similair to checking a bicycle innertube for leaks. So there are just the 2 Vaccum lines? Looks like they would be very easy to replace. Where would I find good replacements? |
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Post by Premier Scooters on Jul 14, 2011 22:12:28 GMT -5
Pull your valve cover off and set the motor to TDC of the compression stroke so there in no pressure on either valve spring. The cam gear will have the 2 small holes lined up with the top of the head and the large hole will be facing out. When looking at The valve springs if the outer spring is broken you will not see even spacing between all of the coils. The spring will feel loose and you will be able to spin it by hand. Look closely with a flashlight. If the springs are fine then check your valve gaps. Set the intake to .004" and the exhaust to .005"
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Post by 2wheelxtreme on Jul 14, 2011 22:18:29 GMT -5
well if there is a hole in you vacuum lines either one of them i suggest you take it off and go to yuor local auto zone and find a fuel line that size or any other rubber hosing that would fit into the connections. you may have to buy a long size of a hose just cut it down to size. Since you are new to scoots as you said im not 100% sure you want to mess with your valve springs as you could easily get confused with nowone to help you out there. my suggestion is take a look if the valve spring may be the issue and if you think you cant tackle the job and the bike continues to run like you say i would take it to a local scooter shop to get it fixed to cause less hassle for you ; ) good luck, john
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Post by edfr on Jul 14, 2011 22:35:56 GMT -5
Backfireing means your running LEAN(NOT ENOUGH FUEL). You could have a VACUMM Leak or loose Carb or hoses disconnected. What is happening is it is SUCKING in EXTRA AIR from someplace and not enough fuel to compensate for the extra air. Take a bottle of SPRAY WATER and start the scoot and let it idle. Then Spray INDIVIDUAL areas around the Carb. By the Clamps where the carb connects to the INTAKE MANIFOLD and were it connects to the AIR FILTER. Then spray the VACUMM hoses . IF YOUR IDLE CHANGES you found an AIR LEAK. If no Air Leaks are found Adjust your Carbs FUEL RATIO SCREW: 1. Turn the AIR FUEL RATIO SCREW COUNTER CLOCKWISE 1/4 turn at at time and Wait 10-15 seconds to allow the engine to catch up with the new setting. IF THE IDLE GOES UP REPEAT one UNTIL THE IDLE DOES NOT CHANGE. Once You Get "THE HIGHEST IDLE OUT OF THE FUEL RATIO SCREW" you may need to LOWER The Idle " USING THE IDLE SPEED SCREW", that is the one on the Right Side with the Spring on it, turn that Counter Clockwise just a little if the Idle is to high. Here is a picture of the Carb and the parts are labled: Lefty LEFT SIDE OF CARB:  RIGHT SIDE OF CARB:  |
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Post by jbbrack03 on Jul 14, 2011 22:52:31 GMT -5
So the idea is that spraying water on a leak will make the engine choke for a second and then you've identified a leaky hose? I believe that one of my vacuum hoses didn't have a clamp on it. I think it was just attached over the jet. Do you think that this could cause my issue? Do auto stores carry these clamps or do you have to order them?
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Post by 2wheelxtreme on Jul 14, 2011 23:19:34 GMT -5
yes they do carry them the clamps would be the same as a fuel hose clamp they come in two sizes i believe the small ones and the larger ones for bigger fuel lines.
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Post by 2wheelxtreme on Jul 14, 2011 23:23:19 GMT -5
oh as to the problem if it didnt have a clamp but was still connected is highly doubtful that would be the problem if it was still connected to the jet.
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Post by jbbrack03 on Jul 14, 2011 23:44:17 GMT -5
Thank you for all of your help. I'm going to check into a few of these suggestions and I will get back to you guys when I have some more information.
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Post by 2wheelxtreme on Jul 14, 2011 23:45:44 GMT -5
okay let us know man lol good luck ; )
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Post by sprocket on Jul 15, 2011 10:58:14 GMT -5
Zip tie all your hoses.. the clamps on these scooter are terrible...
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Post by jbbrack03 on Jul 15, 2011 19:32:06 GMT -5
That's a good idea. I'm going to try that tomorrow. I'm stuck at work today, but I should have some time in the morning tomorrow. I'm going to change the oil and the gear oil, pull the carb and check the idle and mixture settings, and replace the vaccum hoses. I'll give it a test run at that point to see if there is any improvement.
I watched a few videos on gapping the valves and I feel confident that I can handle that. I ordered a spacing tool that should be here in a few days. I also ordered a #115 Main Jet for the Carb. I'm betting that the valve gaps are off. It's an early 2008 and I doubt that it's ever really been serviced in this way. So we will see what happens.
For this bike, what would you recommend for the spacing for the Valve's?
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Post by sprocket on Jul 15, 2011 19:37:37 GMT -5
Generally, .004INCH intake and .005INCH exhaust, some back them of by .001INCH each... Use the cam sprocket to align the engine..not the flywheel it is totally inaccurate... Attachments:
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Post by jbbrack03 on Jul 18, 2011 20:24:49 GMT -5
Just wanted to give you guys a quick update! I changed the oil and pulled the carb again. I made sure that I wasn't getting any leaks from either the vaccum or fuel lines. I adjusted my idle and now I'm idling at around 2k and then I adjusted my fuel/air ratio. Boom!!! Now I'm able to get it up to 47 MPH and I'm getting 8K for my RPM's. Considering that I'm a 230 LB fat ass, I am pretty happy that I'm getting that speed from stock stuff. At least it's driving fast enough to be safe on my roads around my house. I'm not getting any weird sounds or bogging anymore. Just beautiful open throttle.
I did order a Feeler Gauge to check on my Valves and those will be here at the end of the week. I also ordered a #115 main jet and I'm going to install that as well. I'll be getting a big refund check in September, so I'll be tackling some heavy modding (airbox, exhaust, bigger carb, CDI, etc). So I'll be back on here to get some help when I'm ready to do that.
Thank you guys for all your help!!!
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Post by ssj4goko4 on Jul 18, 2011 21:43:14 GMT -5
sounds like your fule mix needs only a bit more tweaking and all will be good.
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Post by edfr on Jul 18, 2011 22:04:27 GMT -5
You really do not need a bigger carb at all. The 24mm carb that is on there is big enough. Just to give the real low-down. I had my 157qmj 149.6cc motor bored out to 62mm and had a 60mm Stroker Crank put in which brought it up to 182ccs. I am running with the 24mm Carb that Was on there with and Just upjetting the MAIN JET to 122.5. Bigger Carb will not do anything for and you will be wasting your money. If your just going to put on a FREE FLOW Filter and take the AIRBOX off all you really need is to go up around two sizes on your MAIN JET so if your current main jet is 110 get a 112 if its a 107 get a 110 that is plenty of fuel.
Also DO NOT CHANGE the Pilot Jet It will be fine with the #35 that they usually come with.
Right now you seem to have it running good, now you need to Tune the CVT, you can get it to go probably little of 50mph if you put in a little heavier weights and GET your RPMS down to 7200-7500, 8k rpms on a 150 is usually the RED LINE you do not want to be running 8k at WOT. The Cy6 engine makes it's MAX POWER right around 7500 rpms, anything over that is just wasted and shortens the life of your motor.
Lefty
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Post by jbbrack03 on Jul 18, 2011 23:01:07 GMT -5
You really do not need a bigger carb at all. The 24mm carb that is on there is big enough. Just to give the real low-down. I had my 157qmj 149.6cc motor bored out to 62mm and had a 60mm Stroker Crank put in which brought it up to 182ccs. I am running with the 24mm Carb that Was on there with and Just upjetting the MAIN JET to 122.5. Bigger Carb will not do anything for and you will be wasting your money. If your just going to put on a FREE FLOW Filter and take the AIRBOX off all you really need is to go up around two sizes on your MAIN JET so if your current main jet is 110 get a 112 if its a 107 get a 110 that is plenty of fuel. Also DO NOT CHANGE the Pilot Jet It will be fine with the #35 that they usually come with. Right now you seem to have it running good, now you need to Tune the CVT, you can get it to go probably little of 50mph if you put in a little heavier weights and GET your RPMS down to 7200-7500, 8k rpms on a 150 is usually the RED LINE you do not want to be running 8k at WOT. The Cy6 engine makes it's MAX POWER right around 7500 rpms, anything over that is just wasted and shortens the life of your motor. Lefty Got ya. So what do I need to do to tune the CVT? What are the weights that you're referring to? |
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Post by jbbrack03 on Jul 19, 2011 18:50:08 GMT -5
Ok. A couple of quick questions. My scooter now idles around 2K and it does feel a bit like it pulls when idling unless you hold the brakes. So is my idle too high?
Also, what tuning do I still need to do to get this running perfectly and maybe get a bit more speed. Right now it's pushing around 6K at 35 MPH and will go to 8K at full speed (45-47 MPH) with open throttle. You guys mentioned that I should only be taking it up to about 7500 RPM for full speed. So do I need to lower my fuel/air ratio a little? Any ideas on what I should do to maybe get it around 50 MPH? Do you still suggest that I check the gaps on my valves?
Also, I noticed that I am hearing a sound that sounds a little bit like a kitchen faucet running. It's like the sound of water running through a faucet. Is this normal or is something else going on? Thanks again for all the help!
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Post by sprocket on Jul 19, 2011 18:58:02 GMT -5
jbbrack03Yup put it on the center stand and adjust the idle until the back wheel just begins to turn then turn it back about 1/4 a turn yes set your valves...and then do a mixture adjustment on a hot engine with the scooter idling...then adjust the throttle again if required... faucet sound could be anything.. perhaps a vacuum leak somewhere around the carb.. or the air filter is falling off... You need to get in there get the panels off and see what is happening...
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