Plagued with overheating problem By skysoldier173d (Read 5,850 times)

[skysoldier173d]

New Road Runner 250 w/257cc Linhai clone. I thoroughly flushed the radiator and engine with water 3 times both fwd and reverse flushes, put in a brand new thermostat and filled the system with Prestone Dex-cool which says it is perfectly safe for all alum sys. parts. But upon a 2 mile road test the temp gauge shoots right over to Big Red. I believe the temp gauge is okay because at idle and for the first 5 to 10 min's it stays low until I put some rpm's to the eng on a road test. I have less than 10 miles on this new Scoot & can't believe that I'm still having these radical problems. I can't take it to the dealer as he is in Dallas, TX, and I'm coastal NC. I have a new water pump on the way that won't arrive until Tuesday (Today is sat 2-19) I took off the front face of the water pump and all looks new inside including the white 6 blade impeller. Will all of the retaining screws now removed I still haven't been able to remove the main pump housing by wiggling and pulling. It seems to rotate about 1/4 inch but beyond that it's sorta stuck. Before I put a long shanked screw driver and started tapping it to try and further the removal I hoped to hear from some of you experts regarding how to remove the main wp housing. I don't want to chance hammering tools around the machined fit and possibly damage the alum. or die cast housing if an easier way can be found to remove the pump. I don't know what else this 257cc Linhai cooling sys to run real hot other than than the water pump. One important test that I wish I would have made was to watch the removed top hose to the radiator and see coolant flowing out of it into a catch container as that would have been pretty much proof that the water pump was pumping. After sufficient warm up time (thermo opened) I never saw any coolant liquid flow moving while viewing down into the radiator with cap removed.

I forgot to mention that when the coolant temp rises to above 160 the fan kick's on but as crazy as this sounds when I place my hand over the front side of the the fan the air seems to be blowing toward the front of the Scoot rather than blowing it thru the radiator air flow from front to rear. Could Chicom scooter tech's be that inept as to put a cooling fan on backwards?? While observing the fastener point around the fan they seem to be laying correctly with the screws fastened into place. Maybe my air flow senses aren't hitting right and my hand is feeling the draw of the air being sucked into the fan. With this problem keeping me down so long of a time maybe my head is playing tricks on me. lol! But I swear it sure feels like air being blown out the front side (toward front fender).
Thanks for any of your thoughts in this. I'm quite frankly running out of possibilities and areas to check.

I badly miss my new Honda Ruckus clone GY6 that became a theft statistic after being stolen from a major shopping ctr parking lot with steering lock engaged. So here I am after sinking a couple of thousand $$'s into this Road Runner 257cc and now 3 weeks later and still no scoot to use. Buses and taxi's to and from work is becoming a real pain. She uses our only 4 wheel SUV for her job as a home hospice nurse. Any help will be greatly appreciated and graciously received. Thanks

Ernie

[ccprof]

Skysoldier173d? Are/were you with the 173rd Airborne? If so, thanks for serving from an old artillery sarge! We're glad you're with us!

[skysoldier173d]

Hi cc prof,
Thank for manning those big guns for our beloved USA. I did spend 2 combat tours with 3/503d Abn Inf of the 173d Abn Bde. I was with the Battalion recon platoon and loved every
moment of the 2 years that I served with them during the central highlands campaigns in Vietnam. The guys I served with were the absolute best our country had to offer. Thanks so much for asking. :=))
I'm still battling the cooling sys problem of my new scoot. the DR gave some some great info. While turning the eng over I saw that the impeller blade of the water pump was spinning so that pretty much indicates the water pump is okay. When the Chicom gauge was red lining I checked the radiator water temp with a digital thermometer of known accuracy and the water temp read approx 175 deg. With the rad cap removed the scoot temp gauge did go down to about the mid level reading. I put the cap back on and in about 5 minutes of idle the reading went back up close to the red line indicator. Also, my hat off to those wonderful Chicom factory scooter techs. The radiator fan is blowing in the wrong direction. DR's fix is next to reverse the polarity of the 2 wires and should correct that problem. I'm thinking about running the eng with the thermostat removed as it only speeds up the warm-up of the scoot and that shouldn't be a problem down here in the Carolina's. I have tried to burp this engine so many times that the scoot maybe is trying to avoid me, LOL! Thanks guys for the warm
greetings and hospitality.
Best wishes and I'll keep trying.
Ernie

[skysoldier173d]

Thanks for stopping me at the last moment I was just about to perform the thermo removal surgery. I'm going to keep up the generic coolant temperature checks and try to nail down this scooter temp gauge as either being good or bad. At present I don't have the necessary coupler to use to insert compressed air into the scoot's system and am working on getting a new compressor as my 35 yr old C.H. finally went kaput. I'm still wondering if bubbles could still be in the system and more burping could be needed. After the water flushes I then refill and top off with new Prestone Dex Cool and I'm exhausting many gallons of the expensive stuff to this point. I don't want to reuse the drained out coolant as I see imperfections and small trash in it.
Thank you,
Ernie

[Cruiser]

Welcome to Scooter Doc, Ernie. The 257cc scoots do not usually have cooling problems. A lit cigarette or some other smoking device held in front of the radiator will show the actual direction of air flow when the fan comes on. The coolant temp in the radiator sounds normal and proves that there is some circulation in the cooling system so the water pump is OK. The fan turning on and off is good and confirms coolant flow. The radiator cap should not affect the temp reading in the cooling system. Having the cap on pressurizes the system allowing it to run at higher temps without boiling over.

I also read someplace that tilting the scoot as far as possible from side to side with the engine running can help in removing trapped air.

[skysoldier173d]

I'll certainly check the temp sensor connections. I worked for Motorola Communications for a large part of my life and am pretty good around anything electrical/electrn and connections. I had a few Harley's in younger years, XLR, Electro-Glide and all were air-cooled. A Vespa 150, Lambretta 175cc scoot and air/cooled ofcourse so my 2 wheel liquid cool equip learning curve is moving rapidly. From what I could see, I did not see anthing below the auto-choke that looked like the bleed screw in the illustration and all the hose were of the small 1/4" vacuum size and fuel line. Did some of the Linhai clones not have a carb with the liquid connection?
Thanks again,
Ern

[skysoldier173d]

I ran the eng up to mid temp; via riding it around the block a couple of 3 times, let it totally cool, top of the radiator with 50/50 mix, start let it warm-up again with cap off and top off again. I did the above maneuver 3 times over a 5 hr. time period and after the last top-off I took it out for a 15 min cruise and midway thru the ride it red lined. Later, I discovered a small trickle leak at the thermostat goose-neck. Must have not seated properly from the last time I changed the thermostat. Next, I removed the gooseneck and reattached it but this time I did not put the thermostat back in. BTW, it's an 82 C. unit. I then fired up the Scoot and ran it for about 30 mins in stop & GO, 45mph sustained on the freeway (still well inside the break in mileage) and low and behold the temp meter stayed mid-way and went just slightly above midway during idle behind a truck at a red light. The idle is the same as with the thermostat in which is a little rough. I'm pretty sure the A/F mix needs to be tended to. I could not find the mixture adjustment screw yet. I'm pretty sure that it's not on the intake manifold end, I'll need to remove the airbox to see if it's on the inlet end of the carb.
Acceleration out of the hole seemed normal and thru mid rpm's all seemed fine. While pulling out of stop there's a low level "rattling marbles" sound that has been there from my 1st test ride remained. Perhaps the sliders. Seems to be coming from the aft eng to CVT area. I suppose that my repl thermostat could have been defective. I have a new one that should arrive on Tues or Wed. but have decided to run it w/o the thermostat for awhile and monitor how it runs and heats. The weather temp around here is supposed to drop alot tomorrow as it has been mid to upper 70's for the past 5-6 days. Wondering if the Chicom mech's might have left a large sponge inside the eng. somewhere, lol. I say that because after I have been doing the complete rad/eng drains into the catch pans and refill the top off's always seem to take nearly a whole gallon of anti-freeze including what I pour into the reservoir.

Thanks to all and will be donating to the site,

Ern

[skysoldier173d]

I rode the scoot 7 to 10 miles with thermostat removed and with the headlight cowling removed and the temp reading stayed midway until I put the cowling, front headlight fairing back on and with the small amt of air louvers the temp went back up to high after riding for a few miles. So now the challenge is going to be where can I locate one of the thermostats you suggest. I will call around locally before I go on line unless you have a good suggestion. I know you have spent much time helping me with this problem and I am truly grateful. The dealer I bought it from in Texas, EVO Sales had one of his new customers from Louisiana call me with the same problems he is having with his Road Runner 257cc Linhai clone. He has already tried all the steps that I have and is in the same rut as myself.
Thanks,
Ern

[skysoldier173d]

Today I successfully located a lower temp thermostat (72 deg C - 161.6 F) Installed and sealed well and test rode the scoot with the headlight cowling intact. Outside temp was approx 65deg F. Test road at 45mph for approx 5 miles and at the 5mi period the temp gauge has rose just a small indication to the left of "H" but still in the white and not the red. This proves that the eng will run cooler with the thermostat installed as opposed to being removed. I'll post a photo of the scoot and front end so you can see the very skimpy 3 little louvers that I don't believe can let enough of fresh air into the radiator intake & fan. Any additional suggestions will be gratefully rcv'd by myself and the other guy, (Jerry) with the same scoot as mine and enduring the same hi temp probs. I think that the solution in my case will be to cut out an area of the fiberglass cowling just in front of the radiator location and either buy or fabricate a fiberglass air scoop or air intake vent device similar to car owner's using the hi-rise intake manifolds used by auto enthusiasts of past decades to direct the flow of air to the carb(s) or fuel injection. The chain car part stores don't stock them any longer, ie advance, Auto-Zone, O'Reillys, I haven't checked Pep Boys yet. May have to go to the Harley dealer or Honda motorcycle shop who might have something or be relegated to the fiberglass & resin cans.
Thanks again Doc,
Ernie

[skysoldier173d]

Here are some pic's of some very pitiful are intake louver air intakes. At 1st glance they look adequate but in my opinion the very narrow width of the slits as seen under the headlights are only approx 1/8" wide. The ribbed louvers seen on the sides under the handlebar grips are the only air outputs (aft of the radiator) and don't have much of openings to deflect the hot air.
Before I attempt to take a can opener to the area under the headlights I think I might greatly enlarge the space inside the louvers with a small roto disk cutter which should allow a lot more air to direct to the radiator where I will have a total of 3 fans, of which 2 fans will be running the entire running time except for cold during the winters.
Thanks,
Ernie

[skysoldier173d]

Radiator output vents shown under the hand grips.

[Cruiser]

It looks like they decided to mess up a good working design like the MC-54-250B style scoot. It looks like the cooling vents were an afterthought which was attached to a scoot which was really designed for a 150cc?

Is the gas tank behind the seat on this scoot?

[skysoldier173d]

Hi Doc,
I'll be showing another pic later of the radiator as Chicom mounted. It's location is behind the 3 dinky 1/8" wide vents and those three (4 counting the one above the fender) are all the vents the wonderful Chicom engineers thought enough to provide. I fully intend to do the Dr. JR radiator fan mod's using 2 switch controlled 4" computer type fans. I like the bracket idea you cleverly used to relocate and rivet on the new fans.
Thanks,
Ern

[skysoldier173d]

Any higher up and the radiator would have been in the instrument cluster.

[skysoldier173d]

As you can see there are 3 already tapped anchoring pts for bolting on some mod's. I was thinking about shifting the rad all the way to the far right and attempt to locate 2 small 4 inchers on the left side putting one on top of the other.