timing marks on a Roketa MC 54 250 B

[jdrogosz]

Hello, I need some clarifications on the timing marks. I come up to 2 separate notches and then an arrow pointer. Which is TDC? My scooters are 08's. My wifes engine started dieing when coming to a stop. I think the exhaust vales are too tight. I adjusted the exhaust valves on teh arrow. The engine starts fine and does not kill from a rev to hitting the brake letting off of the throttle. The only prob it is noisy now. I think the arrow is not TDC. Any help/ideas would be great. I do have a service manual on a PFD. It may be helpful to someone else. Thanks for reading my entry.

[katoranger]

Welcome. I am going to move this post down to the scooter forum.

Allen

[phil]

im going to tell you something that may make me sound stupider than i am and start a fight that this isnt "proper procedure" but
1. in the direction of rotation the first mark is a fire or sparking the second is tdc, since it has to fire before tdc, i can explain that but its unimportant.
2. rule #1 dont count for much, when adjusting valves without a lot of details once the lobe is pointed away from the lift clearance is made examples would be adjusting the intake valve while the exhaust valve is open, the point im making is if you used the wrong mark the clearance would be the same
3. this is the important one when adjusting clearance if you can slide the next size gauge in your wrong do it again.
when i adjust i add .001 (.002 gets .003) the extra you cant hear but may keep from burning a valve or bending one at high high rpm once they wear i know everyone going to say this is wrong so before you say im doing it wrong check yours, the clearance will be the same untill it starts to lift 8O.
your problem is most likely you adjusted them too loose not at the wrong time give it a try let me know :lol:

[jdrogosz]

That makes sense, I was confused about 3 diffferent marks. So you think it should be TDC at the second mark? Then what is the arrow head mark. I'll try to get a picture posted. Thanks for your reply and input. I was thinking of checking thr gap at all three marks which would confirm which mark it TDC. Keep in touch.

[forchetto]

The top dead center mark is usually marked with a "T". Lining this up with the arrow index mark on the casing is only part of the procedure. It has to be "top dead center" on the compression stroke to be able to adjust the valves, not on the exhaust stroke.

You can tell you're on compression because both valve rockers will feel loose, meaning the valves are fully closed.

[kczukiman]

Check this thread out.I have the same type of scooter and adjusted my valves a couple of weeks ago.It made a big difference.Much better take off and top end.Ran much cooler too.
http://scootdawg.proboards.com/index.cgi?board=tipsandtricks&action=display&thread=16205

P.S. intake .004
exhaust .005

[jdrogosz]

THANK YOU, that site spelled out exactly what I could not figure out. Thanks again, great info :D :D :D :D

[kczukiman]

Your welcome.Thats a great site for scooters.It helped me bunch.

I am adjusting the valves and need info on the timing marks. As I turn the engine I see three different marks.