jonway overheating By daven68 (Read 7,837 times)

[daven68]

Hi, great board. I am looking for some help with some over heating issues. Paid 140$ to my local repair shop and they didn`t fix it. In fact after examination of the bike I believe all that was done was replacing the coolant. Scoot is a 2007 model jonway, yy250t-2 . radiator fan previously died and has been replaced and does now appear to be working. Scooter runs cool, about 1/4 on the gauge for about 20 mins then shoots up to almost red line after that. Left just idling it seems to stay cool, fan comes on as it should. after about 20 minutes of riding at 45 + mph is when it overheats. The bike is now dissembled and I have completely removed the thermostat from the housing. My question is , could running with no thermostat cause any problems? Seems like this bike has always run smoothest when running cold. Any other suggestions would be greatly appreciated. Thanks,
Dave

[JR]

First of all welcome to the forum! Now generally when one says YY250T it means vertical CfMoto clone engine but even if it's the horizontal linhai two things that are a must and it MUST have the thermostat in place and it's got to be air free as in you've got to burp the air out.

Here is the how to on burping the linhai and it's the same for the Cfmoto clone as well;

thescooterprofessor.proboards.com/index.cgi?board=cool&action=display&thread=24

How many miles on the scooter? Has it been sitting for any long periods of time? We had a member sometime ago that had fits with his cooling system and he finally found the thermostat housing and part of the system partially clogged up and afer a good cleaning and flushing his went back to normal.

So let us know about the engine and we're here to help.

JR

[cruiser]

Welcome to the forum, Dave. JR has great advice. As a matter of fact, here is the thread for a 2008 Jonway YY250T-2 that also had a heating problem:

thescooterprofessor.proboards.com/index.cgi?board=250classchinese&action=display&thread=23

[daven68]

Hey guys, thanks for the quick response. I have been reading through the threads you suggested and all others i can find as well. I believe it was on another forum where i read of someone with the same engine and problem removing the thermostat and fixing the issue , which was where I got the idea. Out of curiosity why do you say it must be installed? I know on a car it mainly gets the temp up quickly for heating purposes. Also can you recommend a good place to order a replacement thermostat from?
I believe the engine must be the CFmoto clone because a friend of mine , with greater knowledge of these things than I have, is working on this with me and he has the Linhai scoot and it is totally different than what I have. As a test I boiled the thermostat and it opened up but the spring had a gap in it, I would say it opened 3/4 of the way maybe a little more .Is that normal or should it have completely compressed tight? We did not find the housing to be clogged up but dont know about the rest of the system yet as we have not completed a flush. Also the bike has about 4000 miles on it . It did sit all winter with periodic idle running where it did get too hot ,but at that point the fan was not operating. since then I have put about 100 miles on it riding it back and forth to the shop on cool days but after what happened I have given up on this mechanic and cant find another local one. Thanks again for all your help.

[cruiser]

Here's a thermostat for the Honda clone engine.

.shop.kidnmekarts.com/Thermostat-250cc-Thermostat-250cc.htm" rel="nofollow" target="_blank">.shop.kidnmekarts.com/Thermostat-250cc-Thermostat-250cc.htm

I believe a thermostat is necessary to regulate the coolant flow through the radiator once the engine is warmed up. If the coolant flows too fast through the radiator, it will not be able to release enough heat and will recirculate back to the engine at a higher temp than if a thermostat is used.

[scootforfun]

Apr 23, 2012 11:45:14 GMT -6 cruiser said:

Here's a thermostat for the Honda clone engine.

.shop.kidnmekarts.com/Thermostat-250cc-Thermostat-250cc.htm" rel="nofollow" target="_blank">.shop.kidnmekarts.com/Thermostat-250cc-Thermostat-250cc.htm

I believe a thermostat is necessary to regulate the coolant flow through the radiator once the engine is warmed up. If the coolant flows too fast through the radiator, it will not be able to release enough heat and will recirculate back to the engine at a higher temp than if a thermostat is used.

Hi cruiser,

I am the friend helping daven68 try to resolve this problem. And honestly, while I am somewhat mechanically inclined, and tend to work on my own vehicles when I can, I am really not all that knowledgeable when it comes to scooters. But I am learning, and do have a 2006 Linhai 300 SuperStrada I have done some work on a bit.

His bike is another animal though, with a different engine. One thing he didn't mention yet is that when we were taking the thing apart, we discovered what appeared to be some kind of air type line that runs to the TOP of the gas tank. It had a major tear in it. Looked like it had been pinched and ripped somehow on assembly. It is connected to a little round plastic piece of some kind, with another similar line coming out from the other side of it. It appears to me to be some kind of vaccum line or something, but not sure. Do you know what this is?

In any case, there was enough slack in the line for us to cut it clean, past the tear, and then remount it on the plastic round piece. We did that. I am just wondering if that line was cut and it was some kind of vacuum line, if it could have been causing the fuel mixture to run lean, and possibly causing this overheating problem? I read somewhere else that this can happen.

Thing is, after all that has been done with the fan replacement and coolant flushing and all, I am really starting to wonder, given that the bike only overheats after running it on the road for more than 20 or 30 minutes, if it wasn't the cooling system at all causing this. But we make take your advise and not run it without the thermostat to see. What you said makes sense.

[JR]

Cruiser hit the nail on the head, even todays modern vehicles will not cool properly without a thermostat and if it is indeed only opening to what appears 3/4 of the way replace it, they are cheap and just another thing to eliminate as a possibility.

I'll also stress the air in the system and what you describe is a classic symptom because as it heats up the air expands and causes bubbles that intefer with cooling.

Pictures of this line will help we have manuals to find out what it is and if it goes to the engine pair system and was sucking too much air through the open line then yes it will run hotter but shouldn't run that much so.

JR

[gowron78]

Here's one a tad cheaper

.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532" rel="nofollow" target="_blank">.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532

[scootforfun]

Apr 23, 2012 17:14:21 GMT -6 gowron78 said:

Here's one a tad cheaper

.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532" rel="nofollow" target="_blank">.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532

Part of the problem is the confusing engine model numbers, which are very similar for Jonway's. There is a YY250T-2, YY250, YY250T, etc.

.jonway-motor.com/1-250cc-motor-scooter.html" rel="nofollow" target="_blank">.jonway-motor.com/1-250cc-motor-scooter.html

That makes finding the right thermostat for it confusing. Will a YY250 or YY250T thermostat fit a YY250T-2???

But thanks for the suggestion. I see some places are trying to sell you the thermostat with the housing. We just need the stat. Housing is fine.

[daven68]

Thanks again to everyone who replied, we will definitely be using your suggestions. I will go ahead and order a new stat and install it hopefully that plus a good system flush will solve the issue. Cant wait to get cruising again. Forgot to mention we live in the mountains so everywhere I go is uphill. If that doesn`t solve it i`m not real sure where to look next.

[JR]

Apr 23, 2012 17:26:37 GMT -6 scootforfun said:

Apr 23, 2012 17:14:21 GMT -6 gowron78 said:

Here's one a tad cheaper

.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532" rel="nofollow" target="_blank">.chinesemotoparts.com/index.php?main_page=product_info&cPath=53_61&products_id=1532

Part of the problem is the confusing engine model numbers, which are very similar for Jonway's. There is a YY250T-2, YY250, YY250T, etc.

.jonway-motor.com/1-250cc-motor-scooter.html" rel="nofollow" target="_blank">.jonway-motor.com/1-250cc-motor-scooter.html

That makes finding the right thermostat for it confusing. Will a YY250 or YY250T thermostat fit a YY250T-2???

But thanks for the suggestion. I see some places are trying to sell you the thermostat with the housing. We just need the stat. Housing is fine.

All the same engine, the CfMoto vertical clone.

.ebay.com/itm/250cc-Thermostat-Scooter-Parts-Free-Shipping-63155-/290702223182?pt=Other_Vehicle_Parts&hash=item43af33e74e&vxp=mtr" rel="nofollow" target="_blank">.ebay.com/itm/250cc-Thermostat-Scooter-Parts-Free-Shipping-63155-/290702223182?pt=Other_Vehicle_Parts&hash=item43af33e74e&vxp=mtr

[scootforfun]

JR, could you possibly explain what the "GY6" designation actually means? That is another source of confusion for me.

[cruiser]

Apr 24, 2012 13:51:25 GMT -6 scootforfun said:

JR, could you possibly explain what the "GY6" designation actually means? That is another source of confusion for me.

Here's a pretty good explanation of the GY6 family of engines.

en.wikipedia.org/wiki/GY6_engine

Notice that they are air cooled and 150cc or smaller. They are based on an old Honda design.

[scootforfun]

The YY250T-2 has a radiator. It has coolant. And yet it considered air cooled?

And how can his be a GY6 then if it is 250cc, and the GY6's only go up to 150cc?

Yes, more confusion. Some of these parts dealers keep referring to the YY250T-2 also as a GY6, with parts that are supposed to fit the YY250T-2.

Dave tried emailing Jonway to ask about a service manual, and not only will they not email him back at all, but you can't access those manuals unless you are a dealer.

[cruiser]

Apr 24, 2012 16:15:54 GMT -6 scootforfun said:

The YY250T-2 has a radiator. It has coolant. And yet it considered air cooled?

And how can his be a GY6 then if it is 250cc, and the GY6's only go up to 150cc?

Yes, more confusion. Some of these parts dealers keep referring to the YY250T-2 also as a GY6, with parts that are supposed to fit the YY250T-2.

Dave tried emailing Jonway to ask about a service manual, and not only will they not email him back at all, but you can't access those manuals unless you are a dealer.

Chinese scoots can be a little confusing:

1. The YY250T-2 is water cooled contrary to the description on the Jonway site.

2. GY6 is a term used for the family of older Honda 50 to 150cc engines. Some vendors use the term for all Honda clone engines. Here's another description of the GY6 family:

.scootertronics.com/hondagy6engine.html" rel="nofollow" target="_blank">.scootertronics.com/hondagy6engine.html

3. Some use the GY6 descriptor for any Chinese clone scooter engine. I have even seen it used for the Linhai clone which was designed by Yamaha.

4. I know of no service manual in the wild for the Jonway maxi scoot (250cc or larger). I wonder if there actually is one even for qualified service personnel. Most people use the service manual for the Helix for the 244cc Honda clone engine. The Yamaha YP250 service manual is generally used for the Linhai clone 257cc engine. The YY250T and MC-54 bodies and frames use the Honda Reflex service manual for the plastic layout and some of the hardware. There are several different wiring diagrams which can be found in our technical library. Most of these diagrams are adapted from generic diagrams since there are very few 100% accurate diagrams originating out of China.