2011 Jonway/Roketa 250cc update

[maddlibb]

Hey Guys, its been a while since I posted, but Ill give you an update on the situation and hopefully you have some good suggestions. Last time I posted almost 3 years ago, my Scoot lost power while topped out at 65ish. Motor still running, no power, I pulled over turned it off then tried to restart, it would'nt restart but was spitting black out of radiator hose. Figure the head was cracked or gasket issue. I worked on it a little hear and there, no luck. about a month ago I said screw it and bought a new carb put it on, changed all the fluids, new battery, new relay, new gasket on the radiator hose and SOB started! over heated, so I replaced thermo and its not over heating now. I have been driving around the niegborhood for about a week no issues. but Im still afraid to go far from home.

My question is, could it have been over heating and I did'nt notice causing oil and antifreeze to mix but not crack the head? or maybe force pressure through the gasket without tearing it? or do you think a carb failure would cause it? I would think a bad head gasket or cracked gasket would cause the two to mix pretty quickly. Thoughts?

[wheelbender6]

I don't have an answer for the gunk coming out of the radiator hose. I'm impressed that you got her running again.

[maddlibb]

Thanks. I took it on the road for a few miles back n forth hitting 45 -50 mph. Rides nice. No heat issues sounds good (except for the damb back brake rattle that seems to be N issue on these bikes) put 25 miles in total riding around good and on state road. I still feel like something is going to go around when I get too far out. Maybe just PTsd .

[Ebuddy]

Could you have had too much oil in it? Perhaps pressure build up, only temporarily forced oil into the cooling system (which might also have messed up the sensor). When you changed everything out you had the correct quantity of all fluids. Carb might have been coincidence. The only other thing that comes to mind is that you said it was spitting black out of a radiator hose, but the cooling system is closed. Could it have been another hose instead? In that case, maybe you were getting oil blow back into the air filter assembly, which was in turn getting back to the carb and gunking it up. Just some thoughts...

[Shadowfire]

One thing you gotta be careful about when purging the air from the antifreeze line is low point on the fill hose. On the my YY250T, the fill hose actually dips down below the top of the radiator then arcs back up.

When you go to fill the radiator after the fluid has been drained, you can only fill it up to the top of the lower hose to the pump; once fluid has risen above that level and pushed out the all the air it can from the bleed hose, there is nowhere for the air to escape, and you basically have a 1/8th full radiator, which doesn't effectively dissipate heat. You need to disconnect the fill cap from the frame, bring it outside the frame and raise it up so that there are no low spots in the hose to prevent air from coming back up from the radiator. At that point you can fill it up and put stuff back.

[rks]

Although I've had bikes of all sizes....from 1965 until the present, I've never had a water cooled one. So I may be way off base here.

It sounds to me like you fixed your problem, when you changed the thermostat. There is another thread on this forum, in the 250+ section, where the fella states he drained the original, crappy black coolant from his scooter. Seems like maybe your scooter had this same black coolant installed at the factory, and that is all that you saw puking from the hoses, when the thermostat stuck, and the scooter over heated.

I'd ride it, and certainly monitor the temperature, as well as the fan's functioning. Stay close to home for a while.....and I'm sure, as the miles add up, so will your confidence in the scoot.

[maddlibb]

thanks for the input, maybe oild was too high and thermo stuck. 2 1/2 years cant really recall so far so good, drove to work today no issues yet!

[maddlibb]

so I have put 150 miles on the sccot, still working but I noticed in hte morning my temp stays between 25% and half, the ride home its in the 90s here so temp stay arounf 75% sometimes hits red then soots back down. do you think I need to burp the lines? does anyone know exactly how to do this? or maybe I didnt put in enough antifreeze? How much should I put it?

[RAM]

I am more experienced with cars, but I have seen similar situation twice . Both times was actually the result of a pinhole. Once in water pump, and the other in radiator. The hole was there, but it would only leak when it was running and building pressure. It would be fine for a while, until enough water had seeped out, and caused the coolant temp to rise. It may be different with scoots, but it may good an idea to run it for a while, then when it seems to be at normal temp, visually inspect the hoses and radiator itself. It may just be a small hole that is visually noticeable under pressure.