Running China Motor backwards ?? Successfully ??

[BigBlue]

O.K.,

I get the point of needing the crankshaft keyway at 2:00. I also understand why the magneto keyway would have to be at 7:00. I just didn't think it through. I had to visualize in my mind what was going on. It would have been easier if I was playing with the engine seeing what was going on.

I deleted my other post since I didn't want anybody else having incorrect information or cause any further confusion.

Chris
AKA: BigBlue

 

[ToyTruck]

O.K.,

I get the point of needing the crankshaft keyway at 2:00. I also understand why the magneto keyway would have to be at 7:00. I just didn't think it through. I had to visualize in my mind what was going on. It would have been easier if I was playing with the engine seeing what was going on.

I deleted my other post since I didn't want anybody else having incorrect information or cause any further confusion.

Chris
AKA: BigBlue

That's ok .

I would prefer to have members here question my setup so as to double check my theory and my execution ...

As for my setup , does it sound right to you ????

I am still confident that some earlier Wrong timing setup Cooked my bearing!

 

[Deleted member 12676]

If timing is too advanced I think it destroys the upper rod bearing before it destroys the crank bearing.

 

[ToyTruck]

Thanks Jaguar

I have been searching for more detail , but I am confident I had I right

As soon as my bearings arrive I will be able to get it going and add more detail if it all works ...

 

[BigBlue]

That's ok .

I would prefer to have members here question my setup so as to double check my theory and my execution ...

As for my setup , does it sound right to you ????

I am still confident that some earlier Wrong timing setup Cooked my bearing!

Jaguar would know about bearing problems and timing since he designed a CDI to work with the engine. It is a possibility that the magneto is slipping since you don't have a Woodruff key.

The 2:00 BTDC crankshaft keyway timing can be verified with the head off. The top of the piston should measure 2mm to 3mm down as shown in this picture from Grubee:


A 7:00 position for the magneto keyway, I am not sure unless you showed me a picture. I can't visualize it.

To set the position of the magneto keyway, it might be best to have the leading edge of the magneto(Green) right of the lowest point of the magneto coil arm(RED) since that is where the magneto is closest to the magneto coil.


Chris
AKA: BigBlue

 

[ToyTruck]

Ok , a couple pics ...
FIRST PIC is NORMAL rotation motor , rotor is turning clockwise about to leave the magneto pickup
The woodruff key is IN in this setup ... TDC is 1:00 so firing point at 15BTDC is 12:00
.

Now this next pick is the way I set the rotor for Counter Clockwise rotation
So the rotor is about to leave the magneto pickup in an Anti-Clockwise motion.

So in this setup TDC is still 1:00 and the new 15BTDC is at 2:00
Woodruff key is NOT in
.

 

[ToyTruck]

Did I get it right or at least close enough not to cause meltdown lol

 

[BigBlue]

I now see why you say 7:00 for the magneto keyway. Pictures are wonderful.

Chris
AKA: BigBlue

 

[Fabian]

If timing is too advanced I think it destroys the upper rod bearing before it destroys the crank bearing.

That's an interesting comment because in 43,000 kilometers and on my 8th engine or it should be better stated that i'm on my 8th crankshaft and connecting rod assembly, i've never had an upper connecting rod bearing fail; "never", yet every "caged (connecting rod big end) needle roller bearing has failed within 700 kilometers, using the standard CDI.

In one case, i replaced the crankshaft and rod assembly (the 7th time), still using the standard CDI and the older style caged big end needle roller bearing. After about 300 kilometers the engine started to make it's first rattling sounds; typical of the big end caged needle roller bearing getting ready to fail.
The standard CDI was replaced with a Jaguar CDI and the engine ran for a further 2,700 kilometers before i decided to replace the crankshaft and connecting rod assembly with the newer crowded roller big end connecting rod assembly.

Even in this case where the big end bearing was damaged and rattling, the upper connecting rod bearing was still in good condition, and it was used in the new connecting rod assembly.
That crankshaft has now clocked up 10,000 kilometers and i've recently pulled the engine out of the bike to replace the crank and rod, because the big end bearing started to get noisy; not in a real bad way, but rattly non the less.
The small end connecting rod bearing has now clocked up 13,000 kilometers and still appears to be in reasonable condition, and i'm almost tempted to throw it in the new connecting rod.

I have no idea how people keep destroying small end needle bearings???, when i've never had one fail.

 

[ToyTruck]

So......

Any opinions on my timing for reverse rotation ???

I believe I have I right , but while a am still waiting for new bearings
I thought I should double check