New Rider
Currently Offline
Hello all, I am new to the scoot world and learning quickly.
Posts: 16 
Likes: 4
Joined: Jun 17, 2014 12:52:27 GMT -5
|
Post by mrscoot on Jan 14, 2015 23:34:19 GMT -5
I have been considering putting in a new cam and I was wondering if anyone have ever dialed in the cam on one of these gy6 engines. I know these engines are chain driven cams and the cam gear is pressed onto the cam. I also know that all these engines are not created equal. One gy6 150 engine is not the same as another gy6 150 engine. They all have slip fit cylinder jugs and that tells us the head and cylinder deck hight from crankshaft centerline will be different from one engine to the next. With an overhead chain driven cam there would be no way to accurately zero in the cam for every engine.
|
|
|
|
Post by tvnacman on Jan 15, 2015 5:36:02 GMT -5
and I thought you wanted to get a read on a cam (you know the whole dial indicator ) .
John
|
|
|
|
Post by dmartin95 on Jan 15, 2015 12:01:05 GMT -5
They all have slip fit cylinder jugs and that tells us the head and cylinder deck hight from crankshaft centerline will be different from one engine to the next. With an overhead chain driven cam there would be no way to accurately zero in the cam for every engine. Can you elaborate? Why will the deck height from the crankshaft centerline be different on every GY6? Isn't that the point of the cam tensioner? |
|
New Rider
Currently Offline
Hello all, I am new to the scoot world and learning quickly.
Posts: 16
Likes: 4
Joined: Jun 17, 2014 12:52:27 GMT -5
|
Post by mrscoot on Jan 16, 2015 18:32:05 GMT -5
The cam tensioner is just that, a tensioner, it only pulls the slack out of the cam chain. With a slip fit cylinder, not every cylinder will be exactly the same hight, in fact it wont be the same from one engine to the next. From the mating surface of the cylinder base to the head deck of the cylinder could be as different by .001 to .010 in. from one cylinder to another. This difference will be seen at the camshaft to crankshaft centerline dimension/length. With the camshaft at the top of the head and the longer or shorter cylinder hight, the cam chain tensioner only pulls the chain slack out of the chain but it does not adjust for differences in length.
This would explain why installing a particular camshaft into a gy6 150 engine and having awesome results, then installing the exact same camshaft into another gy6 150 engine and have very little results or none at all. Dialing in a cam zeros in the camshaft lobe centerlines per manufactured specifications to the crankshafts exact TDC. What I am trying to get at is about degrees of rotation of the crankshaft to the camshaft which could vary by as much as +/- 0-5 degrees or more at the cam. Major power gains or losses can be had with as little as +/- 1 degree off cam centerline.
I know the cam manufacturers for these engines do not give out there cam spects so I would have to retrieve my own cam specs from the particular cam that I am interested with. Then with the specs that I get from that cam, I would need to use a computer based program such as Desk Top Dyno, input my cam specs and run the program to find the optimal cam dial-in for best possible engine performance.
|
|
|
|
Post by jerseyboy on Jan 16, 2015 18:55:21 GMT -5
These motors are made out of swiss cheese from the chinese,,not sure how long it would stay dialed in like you mention,,after time and high RPM's things will change no matter what you do.
I just say put the cross hairs on and have the cam gear perfectly level with plane of head,,leave well enough alone,,sounds way to complicating to me for a GY6 motor,,now if we where talking about a Honda RA121E V12 engine that would be a different story,,but these are little cheap toys to have fun with.Where else could you get a brand new motor/trans for $300 ready to drop in and gooooo!!!..lol
BTW-I noticed awesome results from my A10 cam along with my big port head and 60mm bore...and all was bolt on except for setting ring end gap...its not broke in yet but it pulls alot harder and sounds throatier than any other 150 scooter I heard.
Definitely open to what you are doing though,,very interesting and I like learning about these technical things.
Tom
|
|
New Rider
Currently Offline
Hello all, I am new to the scoot world and learning quickly.
Posts: 16
Likes: 4
Joined: Jun 17, 2014 12:52:27 GMT -5
|
Post by mrscoot on Jan 17, 2015 18:37:19 GMT -5
I understand all about these scooters as toys and I do have so much fun on my scooter. I have been a custom car, hotrod and restorer as well as an engine builder for a few of the SCORE off road racers and doing things such as cam dialing, zero decking piston and cylinders, fly cutting and cc'ing/porting heads... really getting into the heavy dirt is fun for me. I have been doing this stuff for longer than I can remember. Then about a year ago a neighbor shows up at my door with this scooter that did not run and he wanted a 50 for it. By that evening I had it running and on the road,,, I have a total blast with it and I have a real itch to turn this thing into a road warrior. I had some medical issues about 4 years ago and had to take a step back from everything that I was doing. Now I feel strong and healthy,,, basically a new life and I am just thinking that maybe I may have redirected my passions. I envision myself going hog wild and low and behold,,, a full on custom road warrior scooter may evolve.
|
|
|
|
Post by jerseyboy on Jan 17, 2015 18:45:34 GMT -5
Sounds like a plan,, Im like you,,been heavy into building and modding bikes,,mostly 2 strokes in the past 35 years,,keep us posted on your endeavors. As soon as it warms up a bit around here I plan on doing some more testing on this little GY6.I have a 3rd gen racing clutch and bell on the way,,Im sure that will compliment the 60mm BBK pretty sweetly  |
|
