|
|
Post by fixedinwi on Sept 4, 2008 20:30:04 GMT -5
hey-
me and my friend are fixing up an old geely jl50qt that is seemingly having a compression issue. we can run a test, but need to know the standard compression in the first place. the ped has 4300miles on it and can acquire parts for cheap, just wondering if i could get some guidance from the pros...
any help would be greatly appreciated.
thanks
|
|
|
|
Post by Karl on Sept 4, 2008 20:35:59 GMT -5
If you could give us an engine number off of it then that would help.
If it's anything like 1PE40QMB then the compression should be between 198 psi - 139 psi.
If it's the legendary 90cc disguised as a 50cc then you'll want to order a rebuild kit for a 90cc Minarelli motor and they're normally found in the ATV's.
|
|
|
|
Post by fixedinwi on Sept 4, 2008 21:02:36 GMT -5
thanks!
where would you find the engine number?
i ran a compression test and found 90 psi...
next action is to try with the exhaust off...
thanks for the help!
|
|
|
|
Post by Karl on Sept 4, 2008 21:36:23 GMT -5
The engine number will usually be on the tranny somewhere. It'll be engraved and obvious.
When you do a compression test, be sure that the engine is warmed up, use the kick starter and hold the throttle wide open.
|
|
vv238
New Puppy Dawg
Posts: 2
|
Post by vv238 on Sept 4, 2008 22:05:57 GMT -5
well we started it up with the electric starter and the throttle was wide open, but there is a small problem, the kick starter doesn't work, we haven't bothered to find out why, it just doesn't work and for the record, the psi was about 100 less than what you recommended, so therein lies our problem
|
|
|
|
Post by motomech on Sept 5, 2008 8:17:04 GMT -5
Read;
ScootDawg Scooter Forum :: The Garage :: 2 Stroke Scooters :: NEED HELP WITH SICK QJ1E40QMB
|
|
|
|
Post by 90GTVert on Sept 5, 2008 9:48:05 GMT -5
Here's a link to the thread motomech referred to... scootdawg.proboards59.com/index.cgi?board=2stroke&action=display&thread=15471Here are a couple of posts in particular that may be of interest to you... The compression is 90-95 psi The 1E40QMB service manual lists 198psi standard and 139psi service limit compression. Before tearing anything down, you can try and torque your cylinder head nuts and re-test to see if it improves. Make sure the threads in your cylinder head aren't damaged while you're there (you prob would have noticed by now... just making sure).  Other than that, a damaged reed valve can cause compression loss, though I don't know that it would be that severe from a reed. If neither of those are the culprit it's probably time to pull off the cylinder/head and see what's going on in there. My experience with compression testing has shown me that readings can vary widely. Techniques(throttle open, right?), gages and length of hose can cause different readings, especially on small engines. To be sure, place your thumb over the plug hole and crank over with the throttle open. It should pop your thumb off with authority. If you suspect the compression is low, the next thing to do is to remove the muffler again and look into the exhaust port. If the rings are stuck(seized), you will see the scoring lines on the piston skirt. You may have to rotate the engine, of course. BTW, it's probably easier to continue trying to resolve your issue in one thread rather than multiple threads. |
|
|
|
Post by fixedinwi on Sept 5, 2008 17:14:52 GMT -5
ok.
the exhaust was not a hinderance to the compression...
neither was loose cylinder head bolts...
nor was it a bad reed...
I also found the engine number, and is the same as pictured above.
I have two questions for you:
1) are their piston rings, head and base gaskets available
and 2) where to obtain them.
Any help would be great, and the help we have been getting has been absolutely immaculate!
Thanks so much!
|
|
|
|
Post by 90GTVert on Sept 5, 2008 17:59:41 GMT -5
|
|
|
|
Post by fixedinwi on Sept 7, 2008 19:38:07 GMT -5
ok-
so tonight I took apart the engine, down to the bottom end.
turns out the head gasket had a small leak
AND
there was some scoring on the inside the cylinder
SO
I need to hone the cylinder and replace all three items...
I'll post my progress once more is finished.
cleaned the bottom end gasket off of the bottom end and the cylinder and both the head and cylinder are soaking in the parts cleaner.
|
|
|
|
Post by motomech on Sept 7, 2008 21:06:43 GMT -5
If, after a light hone, you can catch your fingernail on any of the score marks, you will need to replace the cyl.(I don't think over-size pistons are available, someone correct me if there is).
|
|
|
|
Post by Karl on Sept 9, 2008 17:42:23 GMT -5
I think you're right, Moto. I've never seen any over bores out there.
|
|
|
|
Post by fixedinwi on Sept 14, 2008 18:35:39 GMT -5
so the parts I ordered were wrong.
all of them.
rings are too big.
base gasket holes dont match, and wouldnt seal if installed anyway.
head gasket holes dont match.
but shipping was obsenely fast.
any suggestions?
I was probably going to return the parts.
|
|
|
|
Post by 90GTVert on Sept 14, 2008 19:04:42 GMT -5
First off, sorry for pointing out those parts. I was under the impression that it was a 1PE40QMB or 1E40QMB from the rest of the thread and the parts I pointed out should be correct for that style of engine. I doubt that parts for scooters will give you any trouble with the return, they are a good company.
I don't know anything about engine options for a Geely. Hopefully Karl or someone can help you out there. Maybe parts for scooters can offer you some insight. I know Karl mentioned a 90cc Geely, but the rings should be too small for your piston if that were the case.
|
|
|
|
Post by fixedinwi on Sept 14, 2008 21:01:50 GMT -5
no, I did find out it was a 1PE40QMB.
and I ordered the parts.
and they didnt work.
If I could figure out how to post pictures... (I took some)
|
|
|
|
Post by 90GTVert on Sept 14, 2008 21:29:19 GMT -5
|
|
|
|
Post by fixedinwi on Sept 15, 2008 15:43:02 GMT -5
pictures: heres my cylinder:  heres the cylinder w/ the new gasket:  here are the two head gaskets (new on top):  and here are the piston rings (new on bottom(larger)):  I got a message from the company that they would take the return and give me a full refund. I am probably going to send them back and throw the moped in the back and use it for a donor. |
|
|
|
Post by Karl on Sept 16, 2008 18:03:27 GMT -5
Is the scooter a Geely JL50QT-16 or JL50QT-21? Those 2 models had the 90cc engines in them. John at Valley Scooters can get those 90cc parts (I think). www.scootersus.com/index.htmlKarl |
|
|
|
Post by fixedinwi on Sept 17, 2008 6:33:04 GMT -5
sorry, its a geely kp50qt-15
at least thats what it says on the side.
could it be a 90cc?
|
|
|
|
Post by Karl on Sept 17, 2008 19:30:22 GMT -5
sorry, its a geely kp50qt-15 at least thats what it says on the side. could it be a 90cc? Do you know if it was listed as a "Turbo" model? If so, then it's probably the 90cc. |
|
|
|
Post by fixedinwi on Sept 18, 2008 7:04:09 GMT -5
no, but is there a way to tell from piston ring size/pison dia./ that sort of thing?
it would be cool if it was a 90...
|
|
|
|
Post by 90GTVert on Sept 18, 2008 9:10:59 GMT -5
I don't know if these specs are correct for geely's 90cc engine, but the 1E50QMF (Minarelli style 90cc) is a 50mm bore and a 42mm stroke.
|
|
|
|
Post by fixedinwi on Sept 19, 2008 15:26:58 GMT -5
no its not a 90...
bore is 43mm
if I remember right...
|
|
