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Post by Damon4t on Jul 12, 2015 10:39:38 GMT -5
Hi guys, just got myself in a jam here. I had my scoot running so good yesterday, i was so happy and loving life..lol but every time i get it running good i got to go and touch things i should not:) I been doing this for a while so i got the basics down and am pretty good at working on my 4 stroke 50cc jonway scooter(Well 83cc), but i would go out for a ride, about 20 to 30 min rides at most, and i would come home and check the temp of my oil and the outside of the head with a multimeter temp check wires, and my oil is about 210 degrees and just putting the wire up against the head i would get a reading of 250 degrees, i am not sure what my oil temp should be, but my guess is somewhere around 130 or so, but just a guess. So i felt like my oil pump was maybe going out on me, so i cracked the case open but as i was doing this all the case bolts were so dam loose i was amazed it ran that good with them bolts that loose, but i changed the pump with one i had from my last upgrade so pretty sure its good, but the big questions are; There is only one way my oil pump can go on as there is a bigger hole on bottom of pump for a spacer or dowel thing, so it can only go on one way, but the one way it gos on the arrow is pointing down? And it needs to be pointing up from what i have read....So i put it together got it running pretty good, but there is 2 problems, 1 is after 45 seconds of it running the exhaust pipe is hot like it was running for 30 mins. 2 as i have it running it sounds like something is banging in to each other, the best way i can word it...Not sure on what to do, this is one of those times i as a forum member really need the help of my friends on 49ccscoot.com Any and all advice questions and concerns are welcomed and very much appreciated....
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trh
Scoot Member
Posts: 43
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Post by trh on Jul 12, 2015 19:15:33 GMT -5
How bad is the banging, and can you feel it? Heat + noise could be it running lean, with harmonics from detonation
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Post by Mrx2002 on Jul 12, 2015 19:42:09 GMT -5
There are two main reasons for an air cooled engine to run hot. One is running lean second is a blockage in the cooling shroud. With the scooter running you should be able to feel air blowing out around the exauast pipe.
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Post by Damon4t on Jul 12, 2015 20:33:29 GMT -5
check on the plastic shroud, and the banging was not to bad, could not feel it though. Updated::: Now i got it running fine but giving it throttle its slow going but will climb (rpms on center stand) But the exhaust gets hot faster then i can shut the garage door and kick the stand to test run it, so i shut it right back down. I had it running so good, but i was hearing noise coming from the bottom end and the heat issue so i decided to check on the oil pump, that is when i found the crank case bolts almost finger tight, all of them to. So its a good thing but i am mad at myself for touching it to..lol I am thinking its in the needle and slide area, so i am gonna put a 100% carb i got ready to go just for these times:)) Still not to sure what it is, my guesses send me on a 3 day wild goose chase so i am open to all thoughts. Thanks again for the help so far guys.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Jul 12, 2015 20:48:20 GMT -5
rod bearing is toast. did you replace the 2 little rubber o-rings that seal the oil pump against the case?
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Post by Damon4t on Jul 12, 2015 23:06:24 GMT -5
no, i did not get them with my new one, and i thought they looked good. Ya, it could be. Is there a way to check it? well guess i could look at it but would i see a loose bearing in the race or something like that? I am not to familiar with the bearings yet, but i think that time is running short for me..
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Post by 90GTVert on Jul 14, 2015 9:01:01 GMT -5
An oil temp of 210F is fine. A cylinder head temp of 250F is fine. With long WOT runs I routinely see oil temps over 250F and CHT approaching 400F. I will say that checking after it's been shut off and you've got the multimeter out isn't a great way to do it. Even if I'm hitting close to 400F, it cools down quite quickly. Problem number one may be that you've tried to fix a non-existent issue.
Make sure you can blow air through the exhaust easily.
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Post by Damon4t on Jul 15, 2015 18:13:15 GMT -5
Thank you for that, ya it just seemed like a good idea at the time, i even sat there for a min before checking it..lol I been screwing a lot of things up on this scooter lately. I had it running so good then i got to go touching it. But i sure could use some help with it, i am so lost right now. Now i get it running nice, i mean it starts before the starter can even make the complete turn, its awesome, but problem 1..It is dead anything past quarter throttle, but will stay running. 2..The cylinder head and exhaust gets super hot after one min of idling. everything else is cool, i even pull the dipstick and touch the oil and its cool as i just put it in. But the exhaust pipe is blazing hot!! This has started after i switched my oil pump with one i had that was good,(Far as i knew) so i opened it back up and put the one that was in it from the start, i did not want to put it back in but i thought it would stop the over heat but no luck, i guess i need to buy a new oil pump, that is the only thing i could say is both my pumps are shot, and the arrow is to be facing up on the oil pump but i can't make either one of these face up as there is only one way it will line up with the bolt holes and in and out ports, that is got my mind all over the place, so i been working on this scooter for 3 days and have done all or most basic things to rule things out but things check out and i am lead right back to this pump with the arrow that don't point the right way..lol going nuts. 178psi perfect vac and fuel flow, new coil plug and tried 4 different cdi's and 2 different exhaust pipes, and on all cdi box's and both exhausts it got just as hot exactly at the same rate of speed to, checked the timing 8 times valves 52 times and tried it at 002 003 004 005 i guess i got to order a oil pump but i am afraid to cause if i can't point this arrow up i will be going crazy, help..lol
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Post by Damon4t on Jul 15, 2015 19:20:09 GMT -5
I get good pressure from the exhaust to, i was thinking maybe i got some gasket maker crap clogged in the port but there is good pressure..
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Post by 90GTVert on Jul 16, 2015 7:39:05 GMT -5
Have you thoroughly cleaned the carb and made sure the main jet isn't clogged?
You should be able to rotate the engine over with the valve cover off when you've got the bottom end together and filled to spec with oil and tell if oil is moving around if that's your concern.
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Post by Damon4t on Jul 16, 2015 15:41:26 GMT -5
Yes, and even tried a carb that came straight off a running scooter, and cleaned my carb, tried up jetting to richen it out and still same issue to the tee. I mean swapping carbs plugs or coil or cdi with different ones and it gets real hot just as fast, i am just afraid to burn up my motor, i do thank you for that oil info, i was worried that was my issue, but after having it running for five mins on center stand i took the cover off and my cam valves and entire area was nicely coated. It was even starting to drip out the bottom so that was awesome to know, i feel a lot better, but can't understand why my cylinder head and exhaust gets so hot so fast, it is not normal at all. I even took my head off completely did a leak test checked it all out, there was a good amount of carbon but not to bad, someone told me it could be electrical so i tried 2 different coils, and bought a new one, no change at all, and its the header pipe that gets hot very fast as the muffler stays cold to the touch, i am thinking of just running it and let it burn, i will find out what it is then...I even changed my gas flushed tank and changed oil 3 times each time going thinner from 20/50 on down, and not even a slight help...craziness in New Hampshire.....
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Post by Damon4t on Jul 22, 2015 19:45:47 GMT -5
It ended up being my cam chain tensioner had a crack in it and broke but you could not see it at all. It always surprises me this dam scooter. I love it though. Thanks for the help guys.
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Post by Damon4t on Jul 24, 2015 19:31:47 GMT -5
Update; It was not the tensioner:( After going through the whole scoot, breaking it down completely and back together again, i can't know matter what get the scoot tuned in properly, it just won't do it, i have it running, starts nice, idles nice, i can gas it a bit but i get backfire like crazy, or it just is crappy but gos, also, the exhaust pipe and head get hot fast, and it sounds weird in the bottom end somewhere, like a 100% lean engine, but its not,(To the best of my knowledge) i have electrical stuck in my head, so i am gonna swap out my stator and pick up tomorrow and see what that does, but everything i switched out no matter what it is, from a carb to 5 different cdis, different pins, slides, intake gaskets enrichers exhausts, soliniods it don't make a bit of difference in the tuning of the scoot or the fast heat up of the head, or that lean sound in the motor, i am a bit worried now, is there something in my bottom end that could be broke? not to sure what is in there besides the crank, oil pump, thats about the extent of my know how in that area of the scoot. Any thoughts i would love to hear them..thanks again guys..
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Post by niz76 on Jul 24, 2015 20:06:44 GMT -5
178 psi compression seems a bit high assuming that's correct. Your sig says 196 psi! At those compressions, pre-detonation seems to be a possibility and may explain the heat?? IDK. Just stretching here. Is the header pipe of the exhaust glowing red hot? Have you experienced any seizes or soft seizes? Just curious what makes you think that it's getting abnormally hot? Fan blowing air correctly onto the cylinder with all shrouds in place?? Bad crank bearings may cause extra friction and heat but usually there's some tell-tale signs or noises that there's something wrong...
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Post by Damon4t on Jul 24, 2015 21:20:16 GMT -5
If i ain't fried something i can't fix then i will be lowering that psi. No glowing as i won't run it for more then a min or two at most, but i am about to take it for a ten min ride though and see where its at then, just don't want to hurt it, as i got so much blood sweat and tears in it:) I really don't know what a soft seize is, or never seized a motor either. Well i did once and it was in a camero and a ton of white smoke came out the exhaust and it coasted to a stop, and sounded like a rod ripped through it..lol but that was a car, i never had anything like this happen with this scooter, i had it and upgraded for 4 yrs. about, and ride maybe 500 miles a yr. snow, and just don't get to do to work or working on it,,I think it is abnormal just when i run it for a min. shut it down,the header pipe will smoke a bit from just dirt a touch of oil left on it witch is normal but in under a min? the muffler part i can hold my face on it cause its so cool but seems pipe gets way to hot for 60 seconds, i am afraid to see what 10 mins would do. I had all plastics on, changed the plug 3 times with a cooler one, i even just swapped the head with a perfect one i had just to rule out something i was just not seeing, but it made 0 difference. I am switching my stator out and trying that now, i inspected the key thing on the end of the crank shaft and its perfect, i checked for play from crank on both ends to the best of my know how and not even a bit of play. This is making me really think its something i have no experience with, cause i been doing this for 6 7 or 8 days now, i lost count.....
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