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Post by joehyundai on Jun 13, 2011 13:06:16 GMT -5
I just picked up a keeway 49cc with a jog engine. The engine was almost completely filled with oil! It seems that it is seeping down from the oil tank when it is sitting. Is the pump maybe bad?
:sos:
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Post by lshigham on Jun 13, 2011 13:15:04 GMT -5
There should be a check valve in the pump that stops the oil draining past the pump when it's not supposed to, sounds like it's broken.
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Post by joehyundai on Jun 13, 2011 14:07:24 GMT -5
Thank you for your reply. So do I replace th pump or is the check valve separate?
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Post by lshigham on Jun 13, 2011 14:42:22 GMT -5
It's part of the pump  |
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Post by marshinman on Jun 13, 2011 17:29:32 GMT -5
Do away with the oil tank and pump and premix, this way you will sure that the engine is always receiving the proper lubrication.
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Post by joehyundai on Jun 13, 2011 19:27:58 GMT -5
Yeah, that was a thought. But don't I need to re-jet the carb? Also then you have the no oil on downhills issue.
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Post by jmkjr72 on Jun 13, 2011 19:33:05 GMT -5
yes you will need to rejet your carb if you do that
and you could have down hill issues with no oil if you are off the throttle
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Post by marshinman on Jun 13, 2011 19:37:43 GMT -5
I have not heard of having to re-jet due to premixing but then again I am not the genius here, talk to Brent about that one.
The no oil down hills?
Once you mix 2 cycle oil with gas it will stay mixed unless it sits for a period of time not being disturbed.
I raced 2T bikes for years and never did I ever have a issue going down hill.
Ask Brent (90GTVert) see what he has to say.
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Post by jmkjr72 on Jun 13, 2011 19:43:25 GMT -5
the problem is if you are not on the gas you are not getting oil
and i doubt on a race course you had to coast down some hills like you would on the road
and a lot of times when you coast on a cvt your clutch will stay engaged and your motor still spinning the revs you would be going down the hill
on a bike you could grab the clutch and your revs would drop
this has been debated for many years thats why i say could
as for upjetting the reason why is the oil displaces fuel so your air fuel ratio will not be right any more
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Post by marshinman on Jun 13, 2011 20:13:44 GMT -5
"the problem is if you are not on the gas you are not getting oil"
If the engine is running and the oil is mixed in with the gas then you are getting lubrication.
"and i doubt on a race course you had to coast down some hills like you would on the road"
This is a two part answer as on a race course you would be surprised of the down hill events, I did mostly endurance races that were anywhere from 20 to 150 miles and were cut through the Appalachian mountains.
"and a lot of times when you coast on a cvt your clutch will stay engaged and your motor still spinning the revs you would be going down the hill
on a bike you could grab the clutch and your revs would drop"
For the most part you use the clutch as a brake when going down hill by down gearing and releasing the clutch slightly and braking at the same time so your RPM's go up.
As for the jetting this I can agree with to some point as the scooter was designed to be using a premix which inserts the oil into the crank area where it is then mixed with the gas. So it is possible that the original jet is not large enough to be able to handle the additional oil which would make it slightly thicker.
My wifes scooter is a TNG LS49 and I disconnected the pump and premix it. The prior person that owned it stoped putting oil in the oil tank and premixed it and they owned it for two years and never had a problem, I have not had a problem with the motor running correctly.
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Post by joehyundai on Jun 13, 2011 21:38:46 GMT -5
Great, Thanks for all the input.
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Post by 2strokd on Jun 14, 2011 7:55:23 GMT -5
Coulda been the oil pump seal as well. Dude showed me were and how they blow out this weekend at the track. The lower seal (closest to the drive gear) blows out and leaks oil all over. The right kind of oil should always be used with injection. Its not the engine that requires a different blend, its the pump that does. One clot or "chunk" of oil hits a tight spot... bye bye seals. I premix as well with some builds. I have mixed thoughts about it. :laugh: , "mixed thoughts". My deal is, injection is a MESS :rant: . Gets your motor all oily and nasty chunky with crud. All of em get that way, good system or not. Premix is security IMO. If you know you mixed that fuel at 40-or50:1 then thats what is getting into the engine. No adjustments or jetting needed. If you burn up from lack of oil then you know it wasnt enough. I run my race scoot at 50-60:1 oil mix with the best results. Then again, i pay almost $10 a pint for the insurance in Redline oil. Hills wont be a problem with premix... Sounds like someone was thinking waaayyy to hard :stumped: . As long as the engine is spinning it will get oil and fuel. If it turns at all and has any compression it is getting wet. Spark or not. Think about it  |
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Post by 90GTVert on Jun 14, 2011 8:43:47 GMT -5
Regarding the jetting issue, it's simple. You mix say 3% oil in your fuel and what is getting to the engine from the jetting is now 97% gas instead of 100% when you were injecting. So if you were using a 100 main jet with injection, it now delivers as much fuel as a 97 main jet. With the more common jet range around 70-80, 3% makes even less difference where a 70 would be a 68 and an 80 would be a 77.6. A lot of folks would never notice a change. If your scoot was on the edge of lean before, you may need to make adjustments.
I don't see hills being a big issue for premix. I agree that if your engine is turning it's making vacuum and that's gonna pull at least some oil mixed fuel from the carburetor for lubrication and cooling. No, I don't think it's enough to keep your engine happy for long... but most of us aren't on hills that big that we can be out of the throttle completely for any length of time. Running your needle and idle settings a little on the rich side will help out some. I've rode a helluva lot of miles on premixed scoots, and I have had no problems other than when I tried to go 80:1, but that's my own stupidity. lol
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Post by lshigham on Jun 14, 2011 15:18:06 GMT -5
When going down hill keep the throttle open as much as possible without increasing speed. There is another way oil can change the mixture, it makes the fuel thicker (not sure if it has a noticeable effect or not though).
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Post by 2strokd on Jun 14, 2011 16:25:48 GMT -5
Say we did just coast down a long hill as most of us do at idle position. I burp my throttle but anyway.....
Even with a oil pump you are still at idle position going down a hill, therefor the pump is only pumping the oil it would with the scooter at idle. No matter how fast it spins it only pumps oil into the engine according to throttle position. Theoretically the oil input would be the same or less than premix unless the pump is adjusted wrong.
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