DO I have to split my case? By retardninja (Read 6,316 times)

[retardninja]

As many of you know I have been installing a big bore kit on my scooter. For some reason after I have it re-assembled all the way to head and the cam is tightened down but it won't turn all the way when i turn the magneto, only about half way and then back halfway. It is definitely binding on something and I think it is the timing chain. I woul'd think it would be very easy for the timing chain to slip off the rear sprocket inside the case OR AM I WRONG? What are the chances of this having happened? Do I need to open my engine case to put it back on or is there another way to tell if it really is off the rear sprocket? Can I put it back on easily? I don't know what else could causing it to bind unless I have the lower chain guide installed wrong. I have never done any of this before so I appreciate your help. My girlfriend is getting pissed my scooter is tore apart in the house , so I better get it fixed soon. Thanks again.

[Alleyoop]

Appears the chain is not on the cam sprocket and is binding:
Check this tear down and build so you can see how to get the chain on the cam sprocket without having to split the case. You will have to take at least the head off and maybe even the jug to get the chain on the cam sprocket. But is easier than spliting the case and taken it all apart.
Alleyoop

www.scooterdoc.proboards.com/index.cgi?board=techtips&action=display&thread=6884&page=1

[retardninja]

Okay thank you Alleyoop. I'll check it out now. You have been a tremendous help. Thank you.

[Bashan]

Is it a bigger cam? Those bigger lobes create considerable resistance when trying to turn the engine. That's why some guys go to a heavy duty starter. It's just a thought

[tvnacman]

Make sure you have it static timed correct. Also try to turn it over by hand with the spark plug out of the engine. I would recheck the valve lash.

John

[tvnacman]

Make sure you have it static timed correct. Also try to turn it over by hand with the spark plug out of the engine. I would recheck the valve lash.

John

[retardninja]

I really appreciate you guys responding. No it's not a bigger cam but I would like to have one. I'm pretty sure I had it timed correctly. I just took the chain guide out and it seed jammed in there because it didn't slide out easily. I was lookin over the tear down thread and now I'm double checking to make sure the intake is the top valve. I also have some triangular aluminum piece that seems to be an extra part from the rebuild kit. I'll post a pic of everything I have left over

*figured this out* Btw- what is "valve lash"? Different name than I heard before.

Thanks again.

[retardninja]

I have figured out the chain binding problem and solved that. So of course there is yet another problem.

After tightening down the valve lash/rocker arm to the head, there is no space at all to slide the feeler gauge between the adjuster screw thing on the rocker arms and the springs for the valve on the head. I have completely removed the valve adjuster screws and the rocker arm still sits tight against the spring heads. It's as if the springs aren't compressed enough.. I am using the same old cam and and valve lash rocker arms. Can I compress the springs more or do I need to buy a new cam shaft and valve lash? This is so much fun I don't care if I ever get it fixed cuz I'm learning how to keep my temper and that is always fun to do on the 4th of July! Thanks for sticking with me...

[royldoc]

Did you replace the head with the bbk? It sounds like you are using a rocker arm assembly for 64mm valves on a 69mm valve head. I found that most stock heads have a valve length of 69mm while most after market heads have a valve length of 64mm.

Valve lash is the gap between the valve stem and the rocker arm.

Roy

[retardninja]

Yeah I replaced the head. I don't know why the guy I bought it from would'nt have at least told me I would need to replace the F*$%^@ rocker arm assembly. Good grief. Thank you royldoc. That has got to be the problem. The guy does ship really fast so thats cool.

Edit: The rocker arms are supposed to be included in the kit- for some reason I didn't get them. I sent the guy a message. I'm sure he'll take care of me.

[royldoc]

Several years ago when I got my first scooter I decided to do a bbk, head included. The heads do not come with a rocker arm assembly, so I thought I could use the old assembly. When I finally got it together I found that the adjustment screws where to short. The stock head had 69mm valve and the new head had 64mm valves. I could get them to the proper gap but couldn't get the lock nut on them. So I did some research and found someone else had the same problem. The suggestion was to put the nuts on the bottom of the rocker arm. This didn't seem right to me so I did more research. This is when I found out that heads came with two different valve lengths. The rocker arm assembly frames are the same for both heads, the difference is the rocker arms.

Roy

[retardninja]

Yeah I checked and the rocker arms were supposed to come with the kit but they were overlooked. The guy is really cool but still it's a drag to have to wait to ride my scooter. Very anti-climactic. It's like always wanting to get a girl and then when you do she's lousy in bed.
Anyways please have a look at my pretty picture because I have parts left over and don't know what they are or where they go.
And I'm bored so I did this to make sure nothing else would go wrong. Thanks again for being there guys. I would be dead in the water without this forum.

Attachments:

[Alleyoop]

[Deleted]

The gear and the part next to it look like an oil pump. They go under the stator behind the fan. Don't know if most guys change it or not with an upgrade. Need special tools for that one.
The tiny brass part is your new main jet. It goes in the carb. Take the bottom off your carb, you'll see it.
Rubber "O" ring looks to fit the intake elbow. and the copper ring is an exhaust seal between the head and exhaust manifold.

[retardninja]

Cool deal. this site is awesome. It really is the best tech help anywhere. As a matter of fact the only tech anywhere help aside from murky answers from TaotaoUSA (theres one other pretty good site scooterrebels but the responses are really slow so it's almost useless if your truly trying to accomplish something. I will stick around this site until I have hot girls to fix my scooter for me, which might happen tomorrow so this might be the last you hear from me and my lottery millions. Thanks for your help. I say that so much it seems kinda hollow, but dammit I'll post a video of the hot girls fixing my scooter to pay you all back.