|
|
Post by jerseyboy on Jun 2, 2014 20:29:49 GMT -5
This is a question I was thinking about earlier today,,I remember reading both was true,,just curious.If they tighten with wear then the motor should get quieter as they do,,and louder tap,tap,tap,tap if vice versa...I did mine last year within the first 500 miles and the motor sounds the same,,it is a little noisy when hot but not bad at all. Hope all are scootin along well this season  Tom |
|
|
|
Post by geh3333 on Jun 2, 2014 20:32:31 GMT -5
It all depends , sometimes they loosen and some times they get tight .
|
|
|
|
Post by jerseyboy on Jun 2, 2014 20:42:49 GMT -5
Yeah I figured they might go either way but you figure if the surfaces of the lifters, cam lobes,and rocker's are getting worn they would not push the valve open as far causing them to get tighter??
|
|
|
|
Post by alleyoop on Jun 2, 2014 20:49:02 GMT -5
There are no lifters the motors are Over Head Cam. You just have the rockers and cam. What usually happens with a head that is not of such good quality is the valve seats start to compress with all the heat and banging shut of the valves. Now the Valve stems moves up and your valve gap goes away. When the head valve seats gets compressed even more then the valve is left a little open no longer sealing and you loose compression.
Alleyoop
|
|
|
|
Post by jerseyboy on Jun 2, 2014 21:17:19 GMT -5
I got ya Alley so they do wear tighter on these gy6 motors,,thanks brother,,good to see you still active here,,missed the forum quite a bit |
|
|
|
Post by geh3333 on Jun 2, 2014 21:34:11 GMT -5
Why would they loosen ? Bad rocker arms possibly
|
|
|
|
Post by geh3333 on Jun 2, 2014 21:37:22 GMT -5
I have a 58.5 ncy racing head but I used the stock rocker arms . I've has them loosen a bit before but never tighten . I set mine to .004 and I've had the exhaust loses to a .006 once . But then again if we are talkin about a stock head and rockers I guess they would either loosen or tighten .
|
|
|
|
Post by jerseyboy on Jun 2, 2014 21:44:46 GMT -5
Yeah Im thinking rocker arms or cam lobes wearing/damaged would have something to do with loosening them but Im not sure..
|
|
|
|
Post by alleyoop on Jun 2, 2014 21:51:21 GMT -5
If they loosen you better start checking your rocker and the adjusting stud lock nut, or it rotated a little loose on you. On most if you take a good look check out the adjusting stud where it hits the stem most should be a little offset to make the Valve turn so it wears evenly. Sometimes just a hair of the tip breaks off on the stud and that will cause a little loose valve. The Cam wear and rocker wear are rare but can happen, but when that happens you will usually hear a slapping sound.
Alleyoop
|
|
|
|
Post by geh3333 on Jun 2, 2014 22:00:36 GMT -5
Thanks alley , I think I may have had a stripped rocker nut on the exhaust , I replaced the entire rocker last yr " with another stock one " I'll find out soon if it loosens again . It's nice to have a ton of extra parts , just sucks they are stock parts . I have three stock variators , one from the engine that came with the scoot , one I ordered after I bought the scoot and one came with the new engine I ordered over 2 yrs ago and all have noticeable different weight , the variator that came with the new engine I bought weighs less then my Koso . Stock parts at vary unpredictable .
|
|
|
|
Post by rockynv on Jun 2, 2014 22:02:56 GMT -5
Poor hardening of the cam lobes or ends of the rockers will contribute to loosening as will a plugged oil gallery to the head or failing oil pump. Sometimes if the first main bearing in the oil circuit from the pump is loose you can have enough drop in oil flow to cause the head and valve train to run dry and wear preamaturely also.
Choice of oil can contribute also in an overhead cam engine especially when air cooled as the head can run very hot and an automotive oil may not be as resistant to coking as an oil formulated for a air cooled overhead valve motorcycle engine.
Tightening can be made worse by using too low an octaine fuel. If you have valves tighten too quickly so that you constantly have to loosen them jumping one grade higher in octain can help.
|
|
|
|
Post by jerseyboy on Jun 3, 2014 7:34:00 GMT -5
Thanks for all the helpful info guys,good to know!
|
|
..BAD TO THE BONE..
