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1986 NQ50 Overheating
Posted: Sat Aug 18, 2012 7:24 pm
by rogerthat
I was wondering if you guys could help me know why my 1986 Honda Spree NQ50 is overheating. It soft-seized twice today. I have all the parts on there. I recently put a new stock piston/cylinder kit on there from Taz, and it has 90 miles so far in the break-in period. I know I get impatient, and want to drive as fast as I can, but I didn't think I was doing too much. I can do about 25mph on half-throttle, and that is mostly how I've been driving it. It wasn't too hot out today, being for Houston, TX weather anyway. I have the muffler on there, with a new exhaust gasket. The stock air box is on there, with a brand new air filter, and it is tight and snug up to the carburetor. The shroud and fan cover is on there. The fan cover is missing the slotted fins, and is completely open. I am wondering if those slotted fins help draw in air some how. I put a post under the parts section to see if someone would sell me one complete. Maybe I just need to be patient. I've read the break-in period is anywhere from 100 to 400 miles. I had another I rebuilt with a new piston/cylinder, and I was hitting 30mph with no soft-seizes in the same amount of break-in time. I guess they are all a little different.
Re: 1986 NQ50 Overheating
Posted: Sat Aug 18, 2012 11:27 pm
by Bear45-70
Seizures, especially soft seizes are not caused by overheats. They are caused by lean jetting or not enough oil and the overheat and oil thing almost always cause hard seizures that require rebuilds. Plug chop.
Re: 1986 NQ50 Overheating
Posted: Sun Aug 19, 2012 12:58 am
by rogerthat
I recently cleaned the entire carburetor, and I put the intake screw at 1.5 turns. It was running like crap, until I cleaned the carburetor. I've tried doing the plug chop, but I am unsure if it's good, or too lean. It's definitely not too rich, as there is no oil on it. I bought a brand new plug, and it's definitely not brand new looking anymore either. Maybe I will post a picture. Is there something else I can check in the mean time? Oil pump? Is there a test to see if it's correctly delivering oil to the system? Thanks!
Re: 1986 NQ50 Overheating
Posted: Sun Aug 19, 2012 1:17 am
by paulpauly7
did you put the head on the right way,check for airleaks
Re: 1986 NQ50 Overheating
Posted: Sun Aug 19, 2012 1:21 am
by Bear45-70
rogerthat wrote:I recently cleaned the entire carburetor, and I put the intake screw at 1.5 turns. It was running like crap, until I cleaned the carburetor. I've tried doing the plug chop, but I am unsure if it's good, or too lean. It's definitely not too rich, as there is no oil on it. I bought a brand new plug, and it's definitely not brand new looking anymore either. Maybe I will post a picture. Is there something else I can check in the mean time? Oil pump? Is there a test to see if it's correctly delivering oil to the system? Thanks!
It is obvious from this post that you have not read the service manual at all, because that is NOT how you set the idle mixture screw and you have no clue how to read a spark plug because you haven't read Wikispreedia to find out either.
Re: 1986 NQ50 Overheating
Posted: Sun Aug 19, 2012 2:57 am
by rogerthat
It is obvious from this post that you have not read the service manual at all, because that is NOT how you set the idle mixture screw and you have no clue how to read a spark plug because you haven't read Wikispreedia to find out either.
Wikispreedia says 1 1/2 turns out for an 86'. Did I miss something? It is referring to the 'air screw' as the 'mixture screw', as it states the 'throttle stop screw' is the 'idle speed screw', which is adjusted for the best idle setting. I referred to it as the 'intake screw' in my post.
As far as plug chops on Wikispreedia, mine looks like Good/Best.
did you put the head on the right way,check for airleaks
The kit I bought only had an EX on the top of the piston, which I pointed towards the front of the scooter. Is that incorrect? My compression is 100psi cold. As far as air leaks are concerned, I wouldn't know how to test for that exactly, except with a compression test.
Re: 1986 NQ50 Overheating
Posted: Sun Aug 19, 2012 3:12 am
by Bear45-70
rogerthat wrote:Wikispreedia says 1 1/2 turns out for an 86'. Did I miss something? It is referring to the 'air screw' as the 'mixture screw', as it states the 'throttle stop screw' is the 'idle speed screw', which is adjusted for the best idle setting. I referred to it as the 'intake screw' in my post. (
Yes, you did. That is an initial setting ONLY. Then with the engine warmed up you adjust the AIR screw (mixture screw or any * thing you want to call it) for the highest idle RPM possible. Only morons set a carb mixture screw by a number in a book. Oh and the idle speed screw is NOT set for the best idle setting, but 1800 RPM + or - 100 RPM. Learn to read all of it.
As far as plug chops on Wikispreedia, mine looks like Good/Best.
Those pictures are telling you nothing, unless you did a correct and proper plug chop and only if you read the base of the insulator and not the tip.
Re: 1986 NQ50 Overheating
Posted: Tue Aug 21, 2012 10:51 pm
by rogerthat
I adjusted the air screw to 2 turns, and it soft-seized. I then tried 2 1/2 turns, and it soft-seized. I thought I would inspect the reeds, and I found out that whoever had the engine before me used the wrong bolts, and one side wasn't bolted down all the way. I cleaned the reeds, and used the right bolts from a spare engine. I took it for a test drive and it soft-seized. I inspected the oil pump, and it was pumping out oil. I thought maybe I should try a better oil, so I drained it, and bought Mutol 710 from a cycle shop. I put it in the oil reservoir, and a little in with the gas, and after test driving it, it soft-seized. So, after all that, I seen how people put air scoops on the fan cover to draw in more air. I went to Home Depot, and bought a 90 degree elbow of PVC, and bolted it over the opening, facing forward. I also bought 2 large bolts for the muffler, as only 1 was on there before. I thought maybe some heat wasn't leaving the base of the engine onto the muffler fully. After driving it for 20 minutes, it didn't soft-seize, so I guess we will see.
Re: 1986 NQ50 Overheating
Posted: Tue Aug 21, 2012 11:12 pm
by zuphilius
rogerthat wrote:did you put the head on the right way,check for airleaks
The kit I bought only had an EX on the top of the piston, which I pointed towards the front of the scooter. Is that incorrect? My compression is 100psi cold. As far as air leaks are concerned, I wouldn't know how to test for that exactly, except with a compression test.
Sounds like you got the piston in correctly, but he is referring to the head. You need to put it on the correct direction or the airflow will not help with cooling the engine.
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 12:01 am
by abreen89
zuphilius wrote:rogerthat wrote:did you put the head on the right way,check for airleaks
The kit I bought only had an EX on the top of the piston, which I pointed towards the front of the scooter. Is that incorrect? My compression is 100psi cold. As far as air leaks are concerned, I wouldn't know how to test for that exactly, except with a compression test.
Sounds like you got the piston in correctly, but he is referring to the head. You need to put it on the correct direction or the airflow will not help with cooling the engine.
yup you want the fins to go left to right so the air can flow over it .. Took me a while to figure that out lol
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 12:16 am
by rogerthat
Oh the head. Well honestly, I don't know. Is the overhang part supposed to be towards the fan, or towards the carburetor? In the manual, on page 6-0, it shows it pointed towards the carburetor, but in the picture on 6-3, it looks like it's pointed towards the fan. I have the fins going left to right, but I'm not sure if the 45 degree angle part on the head points forward/right or backward/left.
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 12:20 am
by abreen89
towards the carb.. for sure i had the same question a few weeks ago. the wat i remember it is that little overhang stops the sair flow and you dont want to stop the airflow at the fan .
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 12:27 am
by rogerthat
Well son of a gun!
I have it on wrong! I can see how the overhang part, towards the fan, could stop the air from rushing over the engine. I will switch it around tomorrow, and see how it goes. I might not need my redneck air scoop after all.
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 12:47 am
by abreen89
rogerthat wrote:Well son of a gun!
I have it on wrong! I can see how the overhang part, towards the fan, could stop the air from rushing over the engine. I will switch it around tomorrow, and see how it goes. I might not need my redneck air scoop after all.
nope stock it all you need just make sure you have the fan shroud and motor shroud and all the bolts for them have and have the head flipped the right direction. Also make sure if you are using the appropriate jet for your setup..
Re: 1986 NQ50 Overheating
Posted: Wed Aug 22, 2012 9:22 pm
by rogerthat
I flipped the head around, and took of my air scoop, and I didn't have any problems. I never would of thought something so simple would make all the difference in the world. I went ahead and put my air scoop back on, and will probably leave it like that for now. I like to drive it WOT everywhere, and this way I know it will always stay cool. Thanks.
