RX3: Engine Top End Rebuild at 22,450 Miles

[SpudRider]

Originally Posted by 2LZ

...Here's a quote from the Lucas website.

"Lucas Fuel Treatment should definitely be used in vehicles that require leaded fuel because it actually replaces the benefits of lead in gasoline...."

Makes ya wonder.

I see that quote for the Upper Cylinder Lubricant at the Lucas website.

https://lucasoil.com/products/fuel-t...fuel-treatment

Walmart sells the quart bottle for $8.87. This seems to be the best value.

https://www.walmart.com/ip/16777813?...&wl13=&veh=sem

[SpudRider]

If you drop the engine for repairs, be sure to examine the O-ring which seals the intake manifold. Make sure this O-ring is not flattened, deformed, or torn, et cetera. Also, be sure this O-ring is installed when you tighten the intake manifold to the cylinder head.



This O-ring is a critical component which keeps dust from entering the cylinder head. Dust entering the cylinder head from either the intake manifold or air filter will eventually cause valve recession of the intake valves.

Once again, I recommend you keep your air filter well oiled, and clean. I use Belray Foam Air Filter Oil for the flat air filters in both my Zongshen motorcycles.

https://www.rockymountainatvmc.com/p...air+filter+oil

[SpudRider]

Here is another tip.

On all my other motorcycles, I always install the piston on the connecting rod first. Then I lower the cylinder onto the piston, while compressing the piston rings. I tried using this method with the NC250 engine, and it did not work. The piston rings of the RX3 are very difficult to compress, and I actually snapped one of the piston rings as I tried to lower the cylinder onto the piston.

Therefore, I ordered another, complete set of piston rings, and used the alternative method of installing the piston into the cylinder first. Here is a summary of that method.

First of all, install a circlip into one side of the piston. Using this method, you will only need to wrestle with a single circlip when the cylinder is resting over the engine case. Then install the new piston rings in the piston. Apply motor oil to the piston rings and the piston skirts. I also spread a little oil inside the cylinder.

Turn the cylinder upside down on a workbench, and turn the piston upside down, making sure the arrow on top of the piston is facing the exhaust side of the cylinder. Using this method, it is very easy to compress each piston ring and push the piston into the bottom of the cylinder. Push the piston into the cylinder, but leave enough room at the bottom to install the piston pin later.

Make sure you install a new cylinder base gasket on the engine crankcase before you install the cylinder/piston assembly.

Take the cylinder/piston assembly to the engine. Tilt the engine to the left, so the cylinder will not easily drop onto the engine case. Now you can install the cylinder/piston assembly over the cylinder bolts, and lower it to the proximity of the connecting rod.

Apply oil to the piston pin, and insert the piston pin through the piston and the connecting rod until it bottoms on the single circlip you installed earlier. Stuff a rag around the connecting rod so you don't accidentally drop the final piston circlip inside the engine. Install the final circlip. Now you can remove the rag surrounding the connecting rod. Finally, push the piston farther into the cylinder, and lower the cylinder onto the engine.

This method is very easy to perform while the engine is removed from the frame, and I might try using this method on my other bikes in the future.

[SpudRider]

If anyone wants to purchase a Cylinder Leakage Tester Kit, I highly recommend the OTC 5609. Most leak down testers don't have a spark plug adapter which fits the 10 mm, spark plug hole of the RX3. Also, this spark plug adapter must be small enough to fit in the narrow, spark plug hole of our RX3 motorcycles. Finally, if the hose comes off the adapter when you try to remove the spark plug adapter, you must be able to retrieve the adapter from the spark plug hole. If this last scenario occurs, you can use the spark plug wrench included with the RX3 tool bag to retrieve the adapter included with the OTC 5609 unit.

The OTC unit is well manufactured, works very well, and is sold for a very reasonable price. This tool also includes a very rugged, molded plastic case. The OTC 5609 works superbly with the RX3 motorcycle, so I highly recommend this unit.

[SpudRider]

Here is another tip.

When removing the engine from the frame, or replacing it, it helps a lot to have an assistant. One person can jack the engine to the proper height and help stabilize the engine on the jack. The other person can twist/tilt the engine to the proper orientation for removal/installation of the swingarm bolt.

If you make all the preparations beforehand, you will only need your assistant's help for about 15 minutes.

[humanbeing]

5.5mm wifi scope/ cam ... (USB version just dozens yuan but needs android phone...) is good for the job
Review of the 8mm http://www.thp.com.hk/forums/thdeta....rum=1&pn=96948

[SpudRider]

I started a thread on the Lucas Upper Cylinder Lubricant at the following link.

http://www.chinariders.net/showthrea...710#post253710

[BlackBike]

Spud, you are one of (if not) the best technical/process writers on this site. Csc should definitely include this in their shop information if they dont already have such a chapter. I know you just did it for the community but is worthy of compensation if they wanted to use it.

I read it all and understood it (which is good since I am not an engine mechanic )

Trouble is, the more I learn, the scarier this stuff becomes makes me wonder about purchasing something like a newly developed 450cc zong engine

[fjmartin]

That was amazing Spud. Thank you for working so hard on this tutorial. I hope to never have to use it...but if I do, it will make things a LOT easier. Take care!

[SpudRider]

Originally Posted by BlackBike

Spud, you are one of (if not) the best technical/process writers on this site. Csc should definitely include this in their shop information if they dont already have such a chapter. I know you just did it for the community but is worthy of compensation if they wanted to use it.

I read it all and understood it (which is good since I am not an engine mechanic )

Trouble is, the more I learn, the scarier this stuff becomes makes me wonder about purchasing something like a newly developed 450cc zong engine

Originally Posted by fjmartin

That was amazing Spud. Thank you for working so hard on this tutorial. I hope to never have to use it...but if I do, it will make things a LOT easier. Take care!

Thank you for your kind words, gentlemen.

[DanKearney]

Thanks for sharing your experience and passing on the knowledge.

Cheers,

Dan K.

[1cylinderwonder]

Spud,
Doesn't 22,450 miles seem quite early for a top end rebuild?
Was it due to inadequate maintenance, manufacturing mistake, or just bad luck?
Kind of a put off for potential buyers.

[SpudRider]

If you read the entire thread you will learn I performed the top end rebuild of the engine because of intake valve recession. This problem was not caused by inadequate maintenance; I maintain all my motorcycles very well. Regarding bad luck, I don't know how bad luck enters the equation. As I stated earlier, I must assume this problem was caused by a manufacturing defect. I hope my problem was a rare, isolated instance.

[jbfla]

Originally Posted by SpudRider

...... As I stated earlier, I must assume this problem was caused by a manufacturing defect. I hope my problem was a rare, isolated instance.

I hope it is an isolated case, too.

While out riding today, I was thinking that most recreational RX3 riders, more than likely, ride 10,000 miles a year or less.

By the time they get to Spud's mileage, the bike will be out of warranty...

jb

[pete]

Originally Posted by jbfla

I hope it is an isolated case, too.

While out riding today, I was thinking that most recreational RX3 riders, more than likely, ride 10,000 miles a year or less.

By the time they get to Spud's mileage, the bike will be out of warranty...

jb

parts are made in batchs not one offs..... So if it's not a assembly issue
from the factoy !!!
Spuds bike was one of the first so any other bikes in the same shipment
could have parts from the same batch...
So read into that what yer want...



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