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Post by keikara on May 16, 2015 12:34:38 GMT -5
Only if oil was getting into the combustion chamber, but if the blow by is back into the motor there would be no smoking, it would in turn just be letting the compression leak past the rings and basically prime the crank case, which in turn would cause it to spit oil. Have seen this happen on a car motor don't know if that could happen on one of the scooter motors, but heck anything is possible. TBA , I would not see much harm since there is already oil flying around in the crank case . I'm sure the crank case oil is reaching the lower cylinder wall anyway . isn't the crank case pretty much open around the inner crank ? Yea the crank case is basically open, however with the added compression leaking into the crank case it will cause it to pressurize, which will cause the oil to foam up and then be pushed out the breather tube on the valve cover due to too much pressure in the engine case. Would be similar to the cooling system on your car when cold there is no pressure but after it has run and starts to heat up it pressurizes the system which allows the over flow to go into the reservoir with out the reservoir to catch it would just blow out the vent tube or blow out a hose if no vent was available. I know it is not an exact match between how the two would work but closest I can think of to compare to. |
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Post by cleverscooterpun on May 16, 2015 16:34:18 GMT -5
Now do you guys think one of ScrappyDog's vent/oil catch systems be worth trying at this point? Or would this just be bandaiding the symptom and not curing the problem?
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Post by ramblinman on May 16, 2015 17:42:20 GMT -5
Now do you guys think one of ScrappyDog's vent/oil catch systems be worth trying at this point? Or would this just be bandaiding the symptom and not curing the problem? i would do an oil change mainly to see how much oil is in there. then fill with about 750ml, that is less than a quart. if it's spewing that much oil something is wrong. either pressure build up or accidentally over fill. i'd do the oil change so you can eliminate one possibility. |
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Post by JoeyBee on May 16, 2015 17:55:42 GMT -5
I agree with ramblinman. Drain your oil completely, then add 750ml of oil. If you still have problems you will know you have a bigger problem than a mere overfill. |
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Post by geh3333 on May 16, 2015 20:58:02 GMT -5
TBA , I would not see much harm since there is already oil flying around in the crank case . I'm sure the crank case oil is reaching the lower cylinder wall anyway . isn't the crank case pretty much open around the inner crank ? Yea the crank case is basically open, however with the added compression leaking into the crank case it will cause it to pressurize, which will cause the oil to foam up and then be pushed out the breather tube on the valve cover due to too much pressure in the engine case. Would be similar to the cooling system on your car when cold there is no pressure but after it has run and starts to heat up it pressurizes the system which allows the over flow to go into the reservoir with out the reservoir to catch it would just blow out the vent tube or blow out a hose if no vent was available. I know it is not an exact match between how the two would work but closest I can think of to compare to. Yeah if the compression is high, he def needs to get that checked. |
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Post by keikara on May 17, 2015 0:10:19 GMT -5
Yea the crank case is basically open, however with the added compression leaking into the crank case it will cause it to pressurize, which will cause the oil to foam up and then be pushed out the breather tube on the valve cover due to too much pressure in the engine case. Would be similar to the cooling system on your car when cold there is no pressure but after it has run and starts to heat up it pressurizes the system which allows the over flow to go into the reservoir with out the reservoir to catch it would just blow out the vent tube or blow out a hose if no vent was available. I know it is not an exact match between how the two would work but closest I can think of to compare to. Yeah if the compression is high, he def needs to get that checked. Not necessarily high compression, just compression getting into somewhere there should not be, and not designed for. |
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Post by geh3333 on May 17, 2015 0:36:35 GMT -5
There is compression on both the upstroke and downstroke . when combustion happens in the chamber the piston is forced downward " I know u know this " but this downstroke does cause some compression in the crank case. Of course that's why there is the breather on the valve cover , but too high of compression in the crank case will Blow the oil out the breather . I think the main issue is why " if compression is high " is this happening " which I'm sure is what u are getting at " . Actually there are not many reasons for possible high compression .
If the compression rings are leaking , the combustion may be passing the rings causing the blowback and extra compression in the crank case . of course if that were happening I would expect the scoot to be running like crap , not just blowing oil .
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Post by geh3333 on May 17, 2015 0:39:27 GMT -5
Wait, so you are saying, with the scooter on the center stand, and the dipstick NOT screwed in, full would read halfway up the hashed segment?? I'm curious about this reply . how were you measuring the oil ? |
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Post by cleverscooterpun on May 17, 2015 0:59:41 GMT -5
On the center stand, dipstick NOT screwed in, full reading to the top of the hashed segment.
Also, as to you previous post, define for me the scoot running like crap? Are we talking about a marginally noticeable loss of power, or a drastic loss?
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Post by ramblinman on May 17, 2015 1:59:57 GMT -5
On the center stand, dipstick NOT screwed in, full reading to the top of the hashed segment. not screwed in should read about half way up the hashed segment. i would say you're about 100ml over (maybe 200). 100ml over proly won't be a problem until you hit WOT. i have accidentally over filled once and oil did spew out of my engine too. |
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Post by ramblinman on May 17, 2015 13:25:36 GMT -5
On the center stand, dipstick NOT screwed in, full reading to the top of the hashed segment. not screwed in should read about half way up the hashed segment. i would say you're about 100ml over (maybe 200). 100ml over proly won't be a problem until you hit WOT. i have accidentally over filled once and oil did spew out of my engine too. i meant to type 100ml over probably won't cause problems but 200ml over would likely cause problems at WOT. |
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Post by geh3333 on May 17, 2015 16:17:52 GMT -5
On the center stand, dipstick NOT screwed in, full reading to the top of the hashed segment. Also, as to you previous post, define for me the scoot running like crap? Are we talking about a marginally noticeable loss of power, or a drastic loss? You are def over filling the scoot . when you overfill the crank case your scoot may seem sluggish. If combustion is passing the rings you will feel a loss of power also. But first I would def drain the scoot and fill it right .and let us know if your scoot is still blowing oil . |
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Post by cleverscooterpun on Jun 20, 2015 21:51:18 GMT -5
Sorry I have not followed up on this.
I was finally able to tinker with scoot again today. I did as suggested and drained the oil, then added exactly 750 ml if 10w 40. I then rode scoot up the highway for a while, hitting an incline and mostly all WOT. All told only rode about six miles, but, unfortunately, returned to find I am again blowing oil.
Any suggestions for my next step?
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Post by pistonguy on Jun 22, 2015 10:09:22 GMT -5
Sorry I have not followed up on this. I was finally able to tinker with scoot again today. I did as suggested and drained the oil, then added exactly 750 ml if 10w 40. I then rode scoot up the highway for a while, hitting an incline and mostly all WOT. All told only rode about six miles, but, unfortunately, returned to find I am again blowing oil. Any suggestions for my next step? How many miles on Her? What Type/Brand of 10-40? Have you been using the same Brand/Type since you have owned it? |
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Post by geh3333 on Jun 22, 2015 23:59:01 GMT -5
Sorry I have not followed up on this. I was finally able to tinker with scoot again today. I did as suggested and drained the oil, then added exactly 750 ml if 10w 40. I then rode scoot up the highway for a while, hitting an incline and mostly all WOT. All told only rode about six miles, but, unfortunately, returned to find I am again blowing oil. Any suggestions for my next step? Did you check the oil level as suggested ?. You always have oil lft over in the crank case. At this point I still don't think its overfilled enough to blow oil , so you probably have an issue with blow by forcing the oil out the vent hose. |
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