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Post by gy6fandan on Jul 26, 2014 15:45:35 GMT -5
I replaced my original cylinder head because it arrived with exhaust valve closed and burned it. I ordered a replacement head and striped out the cylinder head cover bolts holes - now repairing. This technique can help you ensure your new / upgraded head matches your original. I used the replacement head for 3,500 - 7,100 miles. Seems to me the template of the original shuld fit exact on the replacement. Anyway, thats the template matching methode. If anyone can offer explinations of how it can be off so much and still work - it would be interesting.   |
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Post by gy6fandan on Jul 25, 2014 13:24:27 GMT -5
Thanks ----> alleyoop  I will check it out..... a 117.5 and 118 main jet could be good for that "fine" tunning.  |
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Post by gy6fandan on Jul 25, 2014 13:02:17 GMT -5
Thanks ---> ramblinman I will check it out  |
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Post by gy6fandan on Jul 25, 2014 12:58:11 GMT -5
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Post by gy6fandan on Jul 25, 2014 10:07:11 GMT -5
After an upgrade ( still tweaking ) finding jet size an issue. Carb is PD24J on 150cc. #120 is simply too rich at running speeds (10mph +) #115 is great at idle and performs decent at running speeds (10mph + 35mph). Runs awful over 35mph However the #115 causes temperature rise of 300 deg in a few minutes during 5 minute test ride....... The 300 deg temp is off the cylinder head / under the spark plug - not oil temp. Sooooo, anyone know where I can find a PD24J main jet between the #115 and #120 size ? Thinking a #117 - #118 would be the perfect medium - but where to get it ?... Anyone  |
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Post by gy6fandan on Jul 25, 2014 10:01:08 GMT -5
UniqueSP --> Thanks for the info  Still in the process of fine tuning... carb jet, exhaust, etc. |
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Post by gy6fandan on Jul 22, 2014 14:00:56 GMT -5
Have a gy6 - 150cc ( STOCK CYLINDER). Just installed a : "Big port cylinder head /stainless steel valves / high performance springs. ( STOCK CYLINDER). What should the valve lash be on such a setup ? Currently set at .004 / .005 but I am thinking with stock cylinder it may be too much |
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Post by gy6fandan on Jul 19, 2014 12:41:25 GMT -5
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Post by gy6fandan on Jul 19, 2014 9:59:05 GMT -5
CAMSHAFT STOPPER - ((( thanks to "Alleyoop" ))) - new subject researched & disscused in this reply. So, thank you Alleyoop.  Because of "Alleyoops" warning in a copy of this thread on another forum, I googled the camshaft stopper and found a discusion in an old "scootdawg" forums dated May 07, 2008. The direct link and title is : OEM Valve Adjustment : scootdawg.proboards.com/thread/8313?80264=undefinedIt is suggested / stated in the above post that ; "This stopper is not on any of the high performance cams with the exception of the c6 cam". I haven't researched / verified this concerning any changes in performance camshafts since that thread dated in 2008 (six years since then). It seems to me that if it (camshaft stopper) was installed on stock camshafts - and - that everyone states not to turn the flywheel counter clockwise during valve adjustment or in any other circumstances that the camshaft stopper surely plays an important role. I will have to remove my new "A9" cam and look for variance btween my the A9 camshatf my stock camshaft. I could not find a "rebuild" or "maintenance" thread / video on rocker arm assymbly. - Just saying it may good for future reference purposses / general maintenence / troubleshooting. |
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Post by gy6fandan on Jul 18, 2014 16:43:41 GMT -5
Just popped in a cylinder head.
Flywheel turns backwards <---- backwards ? I though it was only supposed to turn forward.
My re-install process "in order" - best as I can remember :
1.) installed 2 hollow metal guides on two of the four stud bolts that the cylinder head slides onto.
2.) put on head gasket.
3.) put on the cylinder head. bolted snugly the 2 side bolts.
4.) put on 2 hollows metal guides that cam holder goes on.
5.) Installed camshaft and made sure marks (holes) were lined up & down.
6.) Installed rocker assymbly.
7.) set valve lash .004 in and .oo5 out.
8.) installed cam chain tensioner.
Stoped at this point because I was re-turning the flywheel to re-check that valve lash was correct and noticed
that the fly wheel turned backwards (due to back pressure ?) about 1/2". I turned gently backwards and it move 3/4 - 1".
What could it be now ?
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Post by gy6fandan on Jul 18, 2014 16:01:01 GMT -5
The head is new - big port with stainless steel valves - the valves seem to be the same size as the original.
The clay test shows .13" clearance in and out.
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Post by gy6fandan on Jul 18, 2014 14:25:57 GMT -5
A9 camshaft on gy6 150cc stock cylinder
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Post by gy6fandan on Jul 18, 2014 13:59:54 GMT -5
I just did a Piston-to-valve Clearance test with modeling clay.
I don't know what the clearance measurements should be for intake or exhaust between valves and cylinder head.
Help would be greatly appreciated.
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Post by gy6fandan on Jul 17, 2014 15:45:36 GMT -5
Is the - "A8" - stock or an upgrade from stock ? If its not stock, what is ?
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Post by gy6fandan on Jul 17, 2014 15:14:05 GMT -5
Alleyoop --> I'm getting conflicting info. 90GTVert stated the following on another post : "You need to put some modeling clay across the top of the piston. It's best to apply oil or some type of lube to each side so the clay doesn't stick so bad after the test. Assemble the top end and set valve lash. Turn the engine over two full revolutions (1 revolution of the cam). Remove the head. You should be able to immediately see if the clay has been broken through, indicating the valves are hitting the piston. Even if not, you need to do farther checks. I cut the clay in half across the centers of the valve indents with a razor, then measure the thinnest point. Be careful not to squish the clay when working with it " I know that you ( Alleyoop ) and him ( 90GTVert ) both know your stuff . So I am really lost on this. However, I found a link to the method 90GTVert stated above : How To Check Piston-to-valve Clearance |
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