Roketa 250cc starting problem By bdplayer81 (Read 9,251 times)

[bdplayer81]

I'm having trouble getting my scooter to start on a regular basis. When I try to start it the starter spins and I can hear some popping but it won't fire up. I can smell gas so it's getting gas. I have also replaced the battery, had the CDI changed, and had the valves adjusted. (All done by a mechanic by the way.) But still no luck. The only time I've been able to get it to fire up is after the battery has been fully charged. It will run and start fine but the next day it wont fire unless the battery has been given more juice. It has happened with the old battery and the new so that doesn't appear to be the problem. I have tested the voltage while under load and it is good. I was hoping someone might have a suggestion for something else to try. This has been an ongoing issue since April and even the mechanic I took it to can't seem to get it figured out. Thanks.

[OMN]

maybe a vacuum leak? not getting enough fuel on startup? i would try taking off the air filter and squirting a bit of starting fluid into the carb. if it immediately tries to start, initial fuel delivery may be the issue. which could mean either a vacuum leak or a worn-out fuel pump.

my scooter does something similar after not being started for several days. i have to crank and crank to get it going. i'm thinking my issue may be the fuel pump. i'm not a fan of the passive, vacuum-operated pump on my roketa.

anyhoo, i'm sure others will have more and better suggestions. good luck! keep up posted on your progress!
ron

[JR]

Jun 26, 2012 11:45:06 GMT -6 bdplayer81 said:

I'm having trouble getting my scooter to start on a regular basis. When I try to start it the starter spins and I can hear some popping but it won't fire up. I can smell gas so it's getting gas. I have also replaced the battery, had the CDI changed, and had the valves adjusted. (All done by a mechanic by the way.) But still no luck. The only time I've been able to get it to fire up is after the battery has been fully charged. It will run and start fine but the next day it wont fire unless the battery has been given more juice. It has happened with the old battery and the new so that doesn't appear to be the problem. I have tested the voltage while under load and it is good. I was hoping someone might have a suggestion for something else to try. This has been an ongoing issue since April and even the mechanic I took it to can't seem to get it figured out. Thanks.

First of all welcome to the forum! Now let me ask you this question? When you say charge the battery and run it and then the next day have to recharge it to start are you saying you just run the scooter a little bit and this happens or you take it for a ride and let it sit overnight and it will not start the next morning?

Two things come to mind. Whether you do it or the mechanic does we need to take a voltage reading on the battery with it running.

Fully charge the battery and if you say it's been tested and is good then so be it but this scooter has a DC powered CDI system and runs strictly off of the battery so if this scooter is not charging then it's not going to start with the battery down, in fact even if it will turn the engine over well if the battery has dropped down under 12Vdc it doesn't want to run.

So after charging the battery start the scooter and put a volt meter on the battery and test. At idle it should be in the 13Vdc range and if revved up it should easily hit 14.0Vdc or better.

Now if it is charging right then here's the other thing that had came to my mind and it's obvious, you've got either a battery with a dead cell or something is drawing it down?

Get a voltage reading and let me know what you find and we'll go from there.

JR

[bdplayer81]

Well, I got the scooter back from the "mecahnic". He didn't fix a darn thing and I got the scooter back in pieces. Mostly body parts are off so I guess that's less I have to do. In any case I put the air cleaner and hose back on and reattached the CDI and the blocking diode. So here's where I'm at... I charged up the battery before trying to turn it over. It has 12.7v when I took it off the charger. I tried starting it a few times and I got the starter to crank but it did not sound like the engine was trying to fire. While I was trying to start it I got a voltage reading on the battery and it went down to 11.4v. Clearly I've lost ground because before I took it in at least I could get it started on an overly charged battery. Now I've got nothing.

[nulldevice]

Are you leaving the throttle alone when you try to start it or are you making the mistake of opening the throttle while cranking it?

[JR]

Jul 20, 2012 14:21:33 GMT -6 bdplayer81 said:

Well, I got the scooter back from the "mecahnic". He didn't fix a darn thing and I got the scooter back in pieces. Mostly body parts are off so I guess that's less I have to do. In any case I put the air cleaner and hose back on and reattached the CDI and the blocking diode. So here's where I'm at... I charged up the battery before trying to turn it over. It has 12.7v when I took it off the charger. I tried starting it a few times and I got the starter to crank but it did not sound like the engine was trying to fire. While I was trying to start it I got a voltage reading on the battery and it went down to 11.4v. Clearly I've lost ground because before I took it in at least I could get it started on an overly charged battery. Now I've got nothing.

Regardless if it will start now or not from your first post you have electrical problems. Now if you want help getting this scooter fixed it's time to open her up and do some tests to find the problem.

Do you have a volt meter and know how to use it?

Have you even checked to see if it has spark?

Now when one has trouble with the things you are having issues with it's not a matter of just saying or diagnosing a "this it the part that you need to fix it" thing, you've got electrical issues.

Can it be fixed? Absolutely. Can someone just say this is what's wrong without you first checking some things that need to be checked? Very unlikely, if they do it is sheer luck.

You've done three things, replaced the battery, CDI and had the valves adjusted and it's obvious that the battery isn't charging and that can be from several things. CDI? It's doing no better in fact since you've got it back from the mechanic it won't run.

Without a full charge on the battery it won't this is a DC powered CDI.

Now this is very little for anyone on any forum to use to get help on fixing this scooter especially for those on forums that don't know much about it to speak of to start with.

So I'll ask again, got a volt meter and know how to use it? If so then I can and will tell you what to check so we can take care of charging issues and any other issues electrically that need to be addressed.

Since it won't start at all now I suspect the mechanic that didn't know how to fix it either has done something and we can address that also if you can and will do the things I need to help you help this scooter. Also pictures may be needed so if you don't have a photo bucket album it would be good to get one, it's free.

JR

[bdplayer81]

Finally had some time to work with the scooter again tonight. I tested the battery and it had 12.5v. I pulled the plug out to check for spark and it looked fouled so I replaced it and tested for spark and there was no spark.

I do have a volt meter but it does not have a diode tester.

[JR]

No need for a diode tester, it can be checked by ohming it but if you have no spark the diode is not the issue with that.

With a battery at 12.5VDc if you have spark it will run provided it's getting fuel.

Ok there is a few things we need to check to see why we are not getting spark.

On your CDI you have 5 wires

black/yellow = feed to coil
green = ground
gray/white = engine kill wire
red/white = pulse or stator pick up wire
black = 12Vdc from key switch

You need to set your volt meter to 20 or above DC volts and turn the key on and see if you have 12Vdc+ on the black wire.

If you do then we do another test. Set the volt meter to a ohms setting and put one volt meter lead to ground and the other to the gray/white wire. Leave the key in the off position. You should immediately read continuity or full ohms resistance.

With the leads still hooked up turn the key on, you should immediately lose continuity or ohms resistance, if you do not then we got to find out what's wrong. Also when you're doing this test make sure the engine kill switch on the handle bars is in the engine run position. The list includes the following possibilities;

Bad key switch
bad engine kill switch
gray/white wire grounded out in the system, trace it out and fix.

Do these tests and get back. Remember the diode has nothing to do with the CDI/coil/firing system.

JR

[bdplayer81]

My wires going to the CDI appear to be a bit different. I have a Green/White, Yellow/Blue, Green, Black/Brown, and Yellow/Black.

Attachments:

[JR]

OK No problem:

Yellow/black = feed to coil
green = ground
yellow/blue = pulse or stator pick up wire
green/white= engine kill wire
black/brown = 12Vdc from key switch

So I'll copy and paste the above tests and use the different colors wires;


You need to set your volt meter to 20 or above DC volts and turn the key on and see if you have 12Vdc+ on the black/brown wire.

If you do then we do another test. Set the volt meter to a ohms setting and put one volt meter lead to ground and the other to the green/white wire. Leave the key in the off position. You should immediately read continuity or full ohms resistance.

With the leads still hooked up turn the key on, you should immediately lose continuity or ohms resistance, if you do not then we got to find out what's wrong. Also when you're doing this test make sure the engine kill switch on the handle bars is in the engine run position. The list includes the following possibilities;

Bad key switch
bad engine kill switch
green/white wire grounded out in the system, trace it out and fix.

Do these tests and get back. Remember the diode has nothing to do with the CDI/coil/firing system.

JY

[bdplayer81]

I'm not sure if I'm doing something wrong but I'm not getting a reading when I check the black/brown wire. I put the red lead on the connection for that wire. Where do I connect the black lead? I know this seems rather elementary but I just want to make sure I'm not doing something wrong. Thanks.

[JR]

Hook the volt meter black lead to the negative side of the battery or you can also touch the green wire to the CDI with the black lead, it is ground. In fact do this so we can verify if you have a good ground too. Without a good ground to the CDI it will not work.

Put the black lead of the volt meter to the battery negative terminal.
Put the red lead of the volt meter to the black/brown wire
Turn the key on

If all is well then you should have 12Vdc+. Now if you do indeed have good voltage then lets do this test to confirm you have a good ground to the CDI.

Put red lead of volt meter to black/brown wire.
Put black lead of volt meter to green wire
Turn on key

If you have good voltage to the CDI with both tests then we need to go through the wires and connections on the CDI to the coil and make sure they are good and making good connection.

Also speaking of grounds, the black battery cable that goes and hooks to the frame needs to be checked. It generally has several wires there usually green and you need to make sure they are clean, no paint on the frame and making a very good connection. A poor ground causes lots of headaches.

Let us know what you find and we'll go from there.

JR

[tvnacman]

Jul 25, 2012 18:48:43 GMT -6 bdplayer81 said:

I'm not sure if I'm doing something wrong but I'm not getting a reading when I check the black/brown wire. I put the red lead on the connection for that wire. Where do I connect the black lead? I know this seems rather elementary but I just want to make sure I'm not doing something wrong. Thanks.

ground or neg battery .

John

[prodigit]

You could always buy a 10A breaker circuit, and install it on the red battery wire.
Open the trunk to disable the breaker when parking the bike. It will also prevent thieves to try to break into the steeringwheel's key, as they would not expect there to be an interruption under the seat.

[rcq78]

I would unhook your alarm,had same problem with my wifes 250b..Went & bought a new battery & still had the problem...So,I have read where the alarm system draws voltage even after the scoot is shut off...So,I unhooked my wifes alarm system this spring & the bike starts better then it ever has.....Bob