moonman314
Scoot Junior
Um.....I'm new at this.
Posts: 17
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Post by moonman314 on Jul 10, 2016 7:30:10 GMT -5
I really don't know the ratio. I'm going to rent a compression tester and test it. Due to the fact I lost of engine power a while back and couldn't get it to run again. And I only use 91 octane, nothing else.
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Post by jkeney on Jul 10, 2016 9:44:16 GMT -5
Did you clean the two surfaces that mate to the gasket? And how about that rejetting of your carb?
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richn312
Scoot Member
2014 Velocity 50cc
Posts: 72
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Post by richn312 on Jul 10, 2016 11:36:18 GMT -5
I can see on your valves the bigger one is not completely round. It looks like its chipped in a few areas. That is prolly why you are leaking. It isnt seating right. That is also a reason for loss of power i believe. Thats just my opinion anyone correct me if in wrong please.
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moonman314
Scoot Junior
Um.....I'm new at this.
Posts: 17
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Post by moonman314 on Jul 14, 2016 4:54:37 GMT -5
So I did the repair, the engine started up beautifully. I cleaned all the gasket areas and put new ones, with some gasket maker to ensure they remain sealed. I have the same size piston the my mechanic sold me (different of course) and I used the jet he provided. So yes, the carb has been rejetted. But now I still have problems. My compression is perfect, but...
On long rides, there is a squealing noise coming from the engine and something that sounds like when 90GTvert forgot to put in gear oil. This sounds like it, but its coming from the engine. Yes I have new gear oil. And another issue is that I'm STILL leaking oil. I don't get it. The gaskets are all new, the cylinder was put together perfect and the gasket doesn't look like it's blown. And there is no oil coming from the breather hose. And top of that. The engine was running fine for 2 day, no issues, just oil leak. And today, I bogged out 6 times. I didn't have a problem starting it up, but first you hear the squealing and it bogs out. Kinda smells like burning oil too.
I don't know what the problem is. I've done everything I can to correct this issue, but the engine either overheats, loses oil, bogs out, or just plain is making noises it shouldn't. Is there anything I can do the fix this with cost? Or would I be better off getting a new engine and scrapping this one?
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richn312
Scoot Member
2014 Velocity 50cc
Posts: 72
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Post by richn312 on Jul 14, 2016 5:35:38 GMT -5
If you are having this many problems with the same engine and its the same problem over and over, i would get a new engine for it.
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Post by 90GTVert on Jul 14, 2016 7:40:14 GMT -5
Given the past issues from your mechanic mentioned here, I wouldn't put a whole lot of faith in his jet selection. Lots of detail here about carb tuning : www.49ccscoot.com/faq/carbtune.htmlThis may be a little easier to get the basic idea : www.youtube.com/watch?v=K5j8gHg5kMcYou could try to do a full thorough inspection of the engine and figure out if the crank is bad, clearances are off, what compression is, and so on. Could have issues related to heat or improper modification somewhere along the way. If you do get a new engine, remember you'll be subject to the same sort of problems unless great care is taken when modified.
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moonman314
Scoot Junior
Um.....I'm new at this.
Posts: 17
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Post by moonman314 on Jul 14, 2016 16:18:52 GMT -5
The crank seems to be good, besides the burning oil smell. When I removed the entire front end to clean the surfaces for new gaskets and the gasket maker. The crank seems to be fine. I referred to your videos, when you were replacing/show us what a bad one looked like. It's weird tho. This morning I poured in so new fresh oil, as I had run dry by the time I got home from school last night. So with the new oil, it ran great, no noises, no bogging out, nothing. Just the dripping of oil along the way.
And I don't seem to have any issues with the carb. The engine starts fine and runs fine, as long as the oil stays in there. I've already went though a whole bottle and a half in a week. Could this mean the engine casing is bad? Or the gasket near the crank blew out?
I checked compression and I got a perfect reading of 124 psi on the compression test. I also brought a brand new head for the engine. This one has shorter valves, which required me to get a new set of rocker arms.
If I do have to get a new engine. I want it to have an 80cc bore. As it's safer for me to get around Vegas. What is the best advice for the "break in." Because on my first BBK, I used that break in oil from AMS Oil. It worked great, I took it easy on the engine, and gave it baby rides. Then the oil leak started to happen and everything went down hill from there.
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moonman314
Scoot Junior
Um.....I'm new at this.
Posts: 17
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Post by moonman314 on Jul 14, 2016 16:22:33 GMT -5
I can see on your valves the bigger one is not completely round. It looks like its chipped in a few areas. That is prolly why you are leaking. It isnt seating right. That is also a reason for loss of power i believe. Thats just my opinion anyone correct me if in wrong please. Yes you are correct. I damaged them like an idiot when I tried to "clean" them. But I replaced the entire head and valve set with new ones. Only these are shorter in length.
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richn312
Scoot Member
2014 Velocity 50cc
Posts: 72
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Post by richn312 on Jul 14, 2016 16:29:54 GMT -5
I can see on your valves the bigger one is not completely round. It looks like its chipped in a few areas. That is prolly why you are leaking. It isnt seating right. That is also a reason for loss of power i believe. Thats just my opinion anyone correct me if in wrong please. Yes you are correct. I damaged them like an idiot when I tried to "clean" them. But I replaced the entire head and valve set with new ones. Only these are shorter in length. So your new head has shorter valves from your stock one?
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moonman314
Scoot Junior
Um.....I'm new at this.
Posts: 17
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Post by moonman314 on Jul 15, 2016 20:54:05 GMT -5
Yes. But the engine runs the same.
I'm going to try one more thing before I give up on this engine. And since I'm a college student, I don't have the income to order a new engine. So I heavily rely on this one. But at the amount of oil I'm losing. Could this be an oil pump failure???
Because after using the gasket maker and repositioning the piston correctly. The engine ran perfect for about a day or two until the oil problem came back. Could the pump be pushing more oil into the bore and the pressure blowing out the base gasket?
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Moat
Scoot Member
Posts: 88
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Post by Moat on Jul 16, 2016 0:10:05 GMT -5
But at the amount of oil I'm losing. Could this be an oil pump failure??? ... until the oil problem came back. Could the pump be pushing more oil into the bore and the pressure blowing out the base gasket? No. The oil pump "pushing" something is not the problem. The real problem appears to be that you're running it out of oil, time and time again - essentially destroying your engine/top end in a matter of minutes/miles. Until you figure out where your oil is being lost - and fix it - you are wasting your time and money by throwing even more new parts at it. Never, ever run an engine low on oil. Using a sealant on base gaskets should be avoided, as it's too easy to over-apply, and it can squeeze out apon torquing the head down and therefore can plug the oil passage that feeds the rockers/cam (IIRC, the only thing the oil pump feeds on a 139QMB). Too, sealants can also act as a lubricant of sorts, allowing the gasket to slide/shift out of place and cause issues/leaks. If you have to use it, use as little as possible... just a tiny, thin film smeared onto the gasket with your fingers, and then only in locations where absolutely wanted/needed. Bob
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Post by 90GTVert on Jul 17, 2016 9:20:59 GMT -5
If I do have to get a new engine. I want it to have an 80cc bore. As it's safer for me to get around Vegas. What is the best advice for the "break in." Because on my first BBK, I used that break in oil from AMS Oil. It worked great, I took it easy on the engine, and gave it baby rides. Then the oil leak started to happen and everything went down hill from there. You should be alright using break-in oil. www.49ccscoot.com/faq/break-in.html
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