To much blow by

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motbro

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Nov 26, 2014
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Well guys im new here so im not sure if this is where to ask this question or not but here goes I bought the ghost racer 7g kit and the motor has had to much or excessive blow by to where it is filling the breather full of oil.So I was wondering if maybe that might be a sign of bad rings or miss aligned rings or either maybe something simpler thanks.
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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Takes a while to break the engine in for a good ring seal. Give it at least 3-400 miles before you worry.
 

Greg58

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May 1, 2011
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Jerry he has a four stroke with piston ring blow by, like Maniac said it should get better after the rings have time to seat.
Motobro, if you can take the bike out on a few trips to put a few more miles on the engine before winter sets in you'll probably see the oil build up reduce.
 

MotorBicycleRacing

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Jul 28, 2010
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Well guys im new here so im not sure if this is where to ask this question or not but here goes I bought the ghost racer 7g kit

and the motor has had to much or excessive blow by to where it is filling the breather full of oil.So I was wondering if maybe that might be a sign of bad rings or miss aligned rings or either maybe something simpler thanks.
The ghost racer 7g kit is a 49cc 4 stroke clone of a Honda GXH 50.

Did you overfill the crankcase with oil?
How much oil did you add?

Is your motor mounted fairly level?

You give no details like how many miles, etc.
 

motbro

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Nov 26, 2014
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Well that was one thing whenever I got done building it I did over flow it the first time I put oil in but I have changed it since then and it should have the correct oil level in it now.Then I did use a level to mount the engine so the motor mount is level then I probally have about 200 or 250 miles on it now but yeah its the GHOST RACER 7G KIT WITH A 4 STROKE ENGINE.Then its on a huffy millennial 29er with a 48 tooth rear sprocket but it has had excessive blow by ever since I had the kit and the neighbor he has the same kit and the first time he rode his it didn't have excessive blow by and still doesn't after 3 or 4 rides on his so I wondering if I just may of wound up with a reject motor or something thanks guys
 

Greg58

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May 1, 2011
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I don't own one so I'm no authority on them but have you pulled the valve cover and checked the oil return holes ? I wonder if oil could be getting trapped on the head and going by the intake valve into the carb, farfetched I know for a new engine but a thought. How often should you adjust the valve lash? Looking at the valve train it has adjuster on the rocker arms.
 

motbro

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Nov 26, 2014
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Well im pretty sure the oil is coming out the crank case vent hose that goes into the breather cause that hose is usually dripping with oil and rite now I have put a longer hose in that hole for the crank case vent and am now venting the blow by under the bike since there is so much oil coming out there.But far as how often you should adjust the valve lash on them im not to sure of but I do know you can adjust them though.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
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If the valves are set with decent lash from the factory, they won't need adjustment until the plastic cam starts getting worn. Six months to a year if you change your oil frequently. My HS 49cc Int: .004" Ex: .004" and they all have 1,000's of miles on them.

They just keep on running....I ran my first HS49 for 2 years before I even checked the lash :eek:
 
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motbro

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Nov 26, 2014
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It also has little to no low end power either from a stop it just sits and chatters real bad until the bike gets going then it smooths out.I thought that might be caused by compression leaking by the piston because of bad rings and filling the crankcase full of excess preasure causeing abunch of blow by.But at first I thought the chattering might be cause by the chain or belt but I have checked them and there good and tight.
 

FFV8

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Oct 29, 2013
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Spring Valley NV
Sounds like it is time for a compression test.

Besides the high crankcase pressure, how is the oil consumption?

Any oil at the tailpipe?

I had a bad Lifan out of the box once. Rings were broken. It had high crankcase pressure, low power & was blowing oil out the tailpipe from day one.

Both compression rings were in two pieces when I tore it down @ 5 hours.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
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Scotto have you ever had one with bad ring blow by like Motbro is having?
No I have not. I've owned at least 8 of these HS 49cc engines in the past couple years, I'm now down to 4 and they all run great still.

A broken ring from the factory would not surprise me though as the assembly of them is pretty sketchy from what I can tell. Quality control....what's that?

Still great little engines for the money ;)
 

motbro

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Nov 26, 2014
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Actually now that you mention it FFV8 I have caught little wiffs of what smelled like oil burning while I was riding it and I just went and checked the exhaust tip and sure enough there is oil on it so I think you may of hit the nail on the head there.But yeah Scotto I agree it isn't or wouldn't be to supriseing if it does have bad ring cause like you said quality control what quality control they wouldn't have clue to what that is over there where these things are made.Then to the construction of the motor on mine looks horrible someone went over board with the gasket sealer and it is just ouzzing out everywhere where they seal the 2 crankcases together.But I have been on kings website and seen that they were having a black Friday sale on the ghost racer 7g motor so I went and ordered me a new motor to replace this one but ill tear the old one down and see if it has bad rings ill let you guys know if it was or not then probally buy some new rings for it and have a spear motor laying around for one of those rainy days thanks guys each and every one of ya for responding so much on my thread it was helpful
 

motbro

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Nov 26, 2014
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Oh yeah does anyone here know the compression psi is suppose to be ill check and see what mine is and you all know if anyone has the specs on that.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
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38
Ridin' inSane Diego, CA.
Oh yeah does anyone here know the compression psi is suppose to be ill check and see what mine is and you all know if anyone has the specs on that.
Not really sure on the specs myself but I would hope at least somewhere between 125-145psi.

And you can never have too many of these little engines laying around. Heck you can throw a spare in your backpack on really long adventures and hardly know it's there! They are that light and that small.....but you really shouldn't have to ;)

dnut
 

motbro

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Nov 26, 2014
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Yeah I would agree they are pretty light little engines and fairly reliable to cause my neighbor he has a tricycle with one of these HS 49CC engine in it and it has been very reliable for him for the couple of years he has had it but I guess every once in awhile a bad one makes it out the door and unfortiately my very first 4 stroke was that one bad that made it but im not giving up them tho.
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
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38
Ridin' inSane Diego, CA.
Yeah I would agree they are pretty light little engines and fairly reliable to cause my neighbor he has a tricycle with one of these HS 49CC engine in it and it has been very reliable for him for the couple of years he has had it but I guess every once in awhile a bad one makes it out the door and unfortiately my very first 4 stroke was that one bad that made it but im not giving up them tho.
That's good too hear, you won't be disappointed in the long run.

Here is a recent thread I started, check it out as it might cheer you up!

Huasheng 49cc

It just goes to show that it does happen but not very often.
 

FFV8

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Oct 29, 2013
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Spring Valley NV
Yep, sounds like broken rings.

If they were broken on install, many times they do no damage to the bore. Replacing the rings will fix it right up if there are no deep scores in the bore.

Even with good QC, bad product still makes it to the customer occasionally.

Hope you can fix it without too much effort.

.
 

motbro

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Nov 26, 2014
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Well since I seen that kings had the ghost racer motors on sale for black Friday for 129 dollars I just wound up going the easy way out and ordered me another motor so hopefully that will fix it.Maybe not the cheapest but I think its probally the easiest tho.
 

FFV8

New Member
Oct 29, 2013
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Spring Valley NV
Sounds like a good plan to me.

Now you can tear the bad engine down at your leisure. If the bore is good, you can go ahead and clean up the ports, deburr everything & put it back together.