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Post by gdoug12 on Jul 7, 2011 13:31:50 GMT -6
Hello, I was recently given a 2008 250cc scooter because the owner could never get it to run reliably. It actually has a JMStar tage, a Jonway tage, and writing on the plastic which has MC-13-250 which is a Roketa? Anyway the tag under the seat says Jonway YY250T-2 so I'll go with that. After reading many of the threads posted I was finally able to get it to start and run consistently by adjusting the valves, replacing the fuel lines, and cleaning the carb. The problem now is that when I start it, after a couple of minutes the temp gauge is at the max and the fan never comes on (it does work I tested by connecting to battery). I have been trying to burp it to remove air but doesn't seem to help. IF I start with the cap off, after a minute or so the coolant comes up and starts pouring out all over the ground. The top of the radiator gets hot, however the bottom remains ice cold which is why the fan doesn't come on I believe. So at this point, it could be air, it could be the thermostat, or the pump, but I was hoping someone may have some input as to where I should start. I'm running out of time before I need to put back together and move to a new home. I thought about removing the thermostat just to see if there was flow from the pump. This scooter only has 27 miles on it and is like new.
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Post by JR on Jul 7, 2011 18:17:56 GMT -6
Ok gdoug12 lets start with what engine, yes I know you listed the YY250T and usually that means the 244cc CFMoto clone but as we all know the Chinese can put any label on any scooter so it could be the 257cc linhai clone too? I read your post and then went in the 250cc section and posted two of my cooling tech files as I haven't had a chance to get all these many files in but not only will I get them in I'll for sure post some when specific problems arise like yours. Now with this you will see both engines with the drain plug locations which will tell which engine you have; thescooterprofessor.proboards.com/index.cgi?board=cool&action=display&thread=24It also gives directions that I put together on the all dreaded burping of the system. Sometimes getting the air out is a PITA and one has to repeat it several times to get all the air out. Now if any air is in the system not only will it run hot the fan may or may not come on at all? Now if it is the helix 244cc here is a PDF file on the cooling system regarding flow, coolant and radiator; thescooterprofessor.proboards.com/index.cgi?board=cool&action=display&thread=25If it is the linhai I'll get that file in next but either engine must be burped completely. Now the spitting out of the coolant does concern me as in you stated a stuck thermostat, or yet a bad water pump? If memory serves me correct the Helix water pump impeller has a locking ring on it that sometimes can come off and the impeller will not spin, my friend Cruiser can answer this or even maybe Daming69 as he's been in this engine too. The linhai has a slightly different set up as the water pump drives off of the same shaft as the oil pump and comes off of the engine in a one unit piece. Now it's highly possible that whoever had this scooter before you didn't do a good PDI and drain the nasty Chinese coolant and the system needs a good flushing and of course you need to put a good 50/50 mix of proper coolant back in. Removing the thermostat on either engine isn't difficult and one can test it with a pan of hot water to see if it's good or bad. Let us know what engine and how we can further help you and again welcome to the forum. JR |
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Post by gdoug12 on Jul 8, 2011 5:36:08 GMT -6
Thanks JR, I realized that afterward. It is the 244cc CFMoto clone which I believe was the copy of the Helix. I will go ahead and drain and flush the system and remove the thermostat to test. If I should go ahead and check the impeller let me know.
Honestly I'm surprised I got this thing to start reliably, there really are no markings to find TDC except for using the cam postioning and two small holes in the chain gear to make parallel with the head. The flywheel seems to have a very slight tic mark on it which may be to check timing but it is more like a small scratch. It still didn't start but then I happen to move the intake valve adjuster a little and suddenly she fired up and has since. I don't want to even consider messing with the valves again until the rest is solved.
Greg
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Post by JR on Jul 8, 2011 7:15:20 GMT -6
Hey Greg as I've stated I'm trying to get all the tech files in my tech section and I'll post a how to and a video of how to adjust the valves as the helix is easier than the linhai to do the valve adjustment. Also I just got this in; thescooterprofessor.proboards.com/index.cgi?board=general&action=display&thread=34Do remember that the engine will not cool properly with no thermostat so if it tests bad then for sure replace it. Also in the same section (general files) there is the Big Guy's PDI and since you're tearing into it you may want to give it a good go over and make sure all is well. Keep watch for the helix valve adjustment in the 250 tech section. JR |
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Post by gdoug12 on Jul 8, 2011 15:21:07 GMT -6
Hi JR,
Quick update for you. I drained the system and at first the liquid was brown and slowly turned to green. But then it quickly stopped and I knew there had to be more. I removed the hose from the inlet side (bottom) of the water pump and whoosh out it came. There was a lot of junk in there kind of like a little kid threw up, it was nasty. I then removed the thermostat, cleaned the housing and tested. It tested good. I then removed the cover from the pump and found that the inlet was totally clogged with that junk. Tomorrow I will take a hose to inlet of the cylinder at thermostat area to try to rinse the motor out, then I'll remove the radiator and try to flush it out as well. Anything you recommend to flush or just use water?
Thanks a ton for all the information!
Greg
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Post by JR on Jul 8, 2011 18:47:10 GMT -6
Greg I would flush with water, flush some more and them more. Just like the burp fill the radiator, start the scooter with cap off, let it warm up to circulate then fill as it needs, put the cap on and run it until it warms up good but not hot. Kill it and let it cool until it's safe to drain. If I were to flush it I would use a safe for aluminum block engine type flush like Prestone and I would make sure I had it very clean before I added new coolant. Also as I mentioned I would give this scooter a good PDI and when you get her cleaned up and burped she's going to do fine and I also got the vavle adjustment instructions in the 250 tech section so you're getting close! thescooterprofessor.proboards.com/index.cgi?board=general&action=display&thread=33JR |
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Post by cptk on Jul 11, 2011 0:03:24 GMT -6
Also if you said the top of the radiator is hot but not the bottom then possibly check to see if there is flow through the radiator bfore you put it all back together...Just a thought...Especially with all the junk you got out of it. I would hate to hear you did all that and still had issues. Great job by the way. Dont give up.. You can get this, and you will be really glad you did.
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Post by gdoug12 on Jul 11, 2011 6:27:06 GMT -6
Great news! I removed the radiator and flushed that out completely. No junk came out of that except that the first amount of coolant had a blackish tint. After that it ran clear. I then stuck the hose nozzle up to the engine where the thermostat plugs in and flushed that out for a bit. That had some rust colored water at first then ran clear. I of course cleaned out the thermostat and water pump housings and made a new gasket for the water pump housing. I put it all back together and filled it up, started it and worked out the air bubbles and what do you know, the fan started to work, the bottom of the radiator became hot, and the gauge never went above 1/4. I'll run it a little like this and then drain and refill again.
Thanks for all the help!
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Post by JR on Jul 11, 2011 8:47:07 GMT -6
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