HOW DOES MC-54B COOLING SYS WORK? By rob00757 (Read 1,299 times)

[ce]

Did you check the temp sensor on the top right side of the engine under the intake? It may have vibrated loose and isn't sending a signal to the fan.

[Bashan]

You're correct, the sensor next to the thermostat connects to the temp gauge. The sensor that screws into the radiator is the thermo-switch and turns on the fan. Have you looked at the Linhai manual? The service on the radiator is applicable to your bike. Rich

[speedracer]

Your system just may have air in it, which will cause it to run hot and not allow the fan to come on. Flush and air evac.

[lceel]

I have a brand new YY250T - actually the same as the MC54-250B, just made by another manufacturer. I'm curious about the rather thick hose that comes out of the body of the scooter and hags down next to the front wheel. There is a brass colored wire around the end of the hose which looks to me as tough it's meant to be a clip to hold the hose on to something. I realize that this is probably a hose from the cooling system - but I didn't think the cooling system vented to open air - I thought there would be an overflow or expansion tank - but then, I think there IS one- and I think this hose originates where the cap sits on top of the sprue hole. I think. I just need someone to tell me that this is normal and I'll be fine. If not - I need to know what that hose is supposed to attach to.

[speedracer]

lceel Your overflow tank is under the gas cover lid which needs your key to open. I can't even think of a thick hose which would be next to your front wheel. You should take a picture of it and post it here. Behind the front wheel is the radiator and there are no hoses which go towards the front wheel.

[lceel]

I will post a picture of the hose this evening.

[Cruiser]

Apr 13, 2012 8:30:06 GMT -6 lceel said:

I will post a picture of the hose this evening.

Does your hose look like this?



This is the carb drain hose. They are usually situated near the carb and may exit anywhere under the scoot. They are usually bolted down to something.

[lceel]

I was going to post a picture but I've discovered a little more about this. There's a plastic tank left of centerline, next to the gas tank filler access. The hose in question is attached to that plastic tank. I get the feeling that the hose wants to connect to something INSIDE the plastic - probably at the bottom of the scoot. I have to undress my bugger because I have a loose wire - if I'm right, it's the brown wire that feeds the running lights (headlights, tailights, license plate lights, etc.). So while I'm in there, I'll see if I can figure out where that flippin' black hose goes.

[speedracer]

The plastic tank is your overflow tank and it's right next to the gas cap. That hose runs to the radiator cap. When your engine is hot it will push fluid to that plastic tank via the hose and when it cools down it can draw fluid back to the cooling system. The wire you are talking about also feeds the fan on 54B which you say you have. On my scooter the wire is white and runs under the belly, splits to the fan then continues on the R/R.

[lceel]

I am still trying to figure out the hose. There's a radiator cap UNDER THE SEAT, right behind the battery - and a small tank there. There's another tank right behind the front wheel well and that's what one end of that hose is attached to. As for the wire coming unseated ... this has happened to several people with the 2011 Jonway yy250t. I wonder why that would be - I wonder if someone either doesn't care about what kind of job they do - or seeing that the right hand handle bar doesn't have a headlight switch - and therefore is shipping to the U.S. - they deliberately allow that connection to be loose.

[jct842]

right hand handle bar is not supposed to have a head light switch, the dimmer is on left

[speedracer]

lceel, I would check again with the engine you have on your scooter as it is not the same engine that is installed on the 54b. I believe you may have the Honda clone engine. Jct is right about the headlights. They are on the left and starter button and kill switch is always on the right side.

[lceel]

Okay - I've figured out the hose. It's the "Vent to air" hose that would carry excess fluid out of the radiator system's overflow tank. There are two hoses attached to the bottle that sits on the left side of the bike, next to the gas tank. One hose comes from above the main radiator hose at the radiator cap (under the battery compartment lid) - it is the hose which carries overflow to the bottle up front, next to the gas tank. If you're sitting on the scoot, this hose would run from UNDER YOU to the back end (lower end) of the overflow bottle. The hose I have which hangs down at the front wheel should actually remain INSIDE the bodywork - but it doesn't - which is where all my confusion stems from.

As for the headlight/running light issue - I KNOW where the headlight stuff is located on the handle bar - it's just that Jonway makes a EURO version of this scoot and IT HAS a headlight ON/OFF switch located just above the starter switch and below the KILL switch. Scoots WITHOUT this switch are only destined for the U.S. market, and I just wondered, aloud, so to speak, if someone in China leaves that connection loose on purpose, out of (maybe) a dislike for Americans. That may be xenophobic and/or racist - but me? I just gotta wonder.

[lceel]

LIGHTS issue turned out to be a bad fuse. :javascript:add("%20;D")