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Post by maconboi on May 19, 2012 9:30:11 GMT -5
Any way to tell if you have 64mm or 69mm valves without disassemble. different valve cover size? head thickness difference? thanks in advance.
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Post by ososlow on May 19, 2012 12:12:02 GMT -5
the only diff ive seen is the length of the adjustment screw on the rockers. but without one to compare it too its probably gonna be pretty hard to see the difference between the two
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Post by larry001964 on May 19, 2012 21:38:05 GMT -5
I believe the way to tell is the stamped number on the case, 1P39QMB has the longer valves. the 139QMB has the shorter...
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Post by maconboi on May 20, 2012 11:19:47 GMT -5
I beleave you're right. ended up just pulling the head and measuring. with the valve in the head it was hard to get a pinpoint measurement but came up less than 69 (around 65) so it's a 64mm thanks guys!  |
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Deleted
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Post by Deleted on May 20, 2012 12:32:01 GMT -5
I believe the way to tell is the stamped number on the case, 1P39QMB has the longer valves. the 139QMB has the shorter... 1P39QMB 1 is for the number of cylinders...The P code is for Horizontal (I have seen 64mm and 69mm on motors stamped P). The 39 is for bore size...Q is for forced air cooling...M is for motorcycle..B is for 50cc An E between P and bore size means 2t like 1PE40QMB= single horizontal cylinder 2 stroke forced air cooled motorcycle engine 50cc 69mm valve motors have a taller valve cover than 64mm. A 69mm valve cover will work on 64mm heads but a 64mm valve cover will NOT work on 69mm heads. Some true 49cc motors have 69mm. never seen 69mm on any 63cc and 72cc factory motors. |
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Post by larry001964 on May 20, 2012 12:57:04 GMT -5
ahhh ok Fast
All I know is i had the longer valves and my rockers didn't want to fit right on the new head ( Too Short ), had to take the top adjustment nut off buy two more of them, then place them under the rocker arm and double nut them..... when I questioned why they were too short, I was told the 1P in the engine code meant I had the longer valves... That was a different forum.. Never heard different until now..
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Post by maconboi on May 21, 2012 20:03:10 GMT -5
yeah and this one was a true 49cc
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boo
Scoot Newb
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Post by boo on Nov 25, 2016 13:34:50 GMT -5
Well this is 2016, so I am sure you have found your answer; but this is my first time on the board and was looking to find information about 64mm valves vs. 69mm valves.
So, the way I tell if it is 69mm or 64mm valves, without pulling the head to measure valves, or interpreting serial numbers, is to view the head from the side.
The edge, of 64mm valve spring seat/keeper, that is closest to the head, will be just below the surface the valve cover sits on.
The edge of the 69mm valve spring seat/keeper, that is closest to the head, will be above that surface so that you can see the start of the spring.
At least, this is what I have observed.
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Post by 90GTVert on Nov 25, 2016 16:34:35 GMT -5
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Post by Deleted on Nov 25, 2016 18:42:14 GMT -5
Well this is 2016, so I am sure you have found your answer; but this is my first time on the board and was looking to find information about 64mm valves vs. 69mm valves.
So, the way I tell if it is 69mm or 64mm valves, without pulling the head to measure valves, or interpreting serial numbers, is to view the head from the side.
The edge, of 64mm valve spring seat/keeper, that is closest to the head, will be just below the surface the valve cover sits on.
The edge of the 69mm valve spring seat/keeper, that is closest to the head, will be above that surface so that you can see the start of the spring.
At least, this is what I have observed.  Bill |
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Post by greggkinney on Dec 19, 2016 21:05:35 GMT -5
Does the different valves lengths make any performance differences or can be used to tuned different? Like higher lift cans or anything...anything
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Post by 90GTVert on Dec 20, 2016 6:19:31 GMT -5
Does the different valves lengths make any performance differences or can be used to tuned different? Like higher lift cans or anything...anything Stock vs stock, I don't think you'd notice anything. The 64 and 69mm heads that I cut in half showed that the 69mm head had more meat on the port roof. That would leave it more open to raising the port and potentially creating more flow where you'd want it. How much difference it would really make, I can't tell you. No idea if the aftermarket is the same way. Cams are the same for 64 and 69mm valves. I'm not sure if the rocker ratios would be any different. That's not a spec Chinese manufacturers are going to cite or that most parts places would care to know. It could be figured out, but it will be a bit time consuming. I may look into that someday, but I don't want to pull my engine to do it right now. |
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