RX3: Engine Top End Rebuild at 22,450 Miles

[jbfla]

Originally Posted by katflap

....

There is a detailed service manual available on the AJP website for the PR5, you and others already know, It uses the same engine as ours. so is seems quite relevant.

(I don't think we have had this one on here before )

It contains a number of procedures, specs, service wear limits and torque settings in regards to the engine and fuel system.

It Might serve as a good companion to your tutorials.

http://motoajp.com/ajp-support/pr-service-manuals/

Thanks for the link to the AJP PR5 Service Manual.

It's nicely done with color photos.

I noticed the AJP engine uses the metal mesh oil filter.

jb

[SpudRider]

Kat,

Thanks for providing the link to the AJP PR5 Service Manual. I have added this link under the "Manuals" subheading in the RX3 Tech Sticky, which is pinned to the top of this forum.

http://www.chinariders.net/showthread.php?t=14228

[rjmorel]

Spud , have you read any of the AJP RX3 like bikes having issues with the valves receding like yours did? There's probably not to many with the miles you put on yours so time will tell. rj

[SpudRider]

No, I have not heard of this problem occurring with any other NC250 engine in other motorcycle. I'm pleased to hear that many RX3 owners have reported their valve clearances have stabilized. However, if you ride many miles and the valve clearances won't stabilize, something is wrong.

[Sullybiker]

Originally Posted by SpudRider

No, I have not heard of this problem occurring with any other NC250 engine in other motorcycle. I'm pleased to hear that many RX3 owners have reported their valve clearances have stabilized. However, if you ride many miles and the valve clearances won't stabilize, something is wrong.

Anomalies in manufacturing. We all know it happens. For instance, if you mosey on over to the Ninja 300 forum, you'll see some examples of big failures at the bottom of the engine; these are rare, and not a 'thing' but once in a while an unlucky owner is going to get a bad surprise. I'm guessing yours is similar.

The sheer number of these things around, I'd be surprised if patterns didn't emerge pretty quickly.

[SpudRider]

Today I passed 27,000 miles on the odometer, which is about 4,500 miles after I did the top end rebuild of my engine. I will check the valve lash again in a week or so. The RX3 is running very well, and getting excellent fuel mileage (70 mpg).

[SpudRider]

Today I checked the valve lash with about 27,250 miles on the odometer. The exhaust valves had closed about .01 mm, and the intake valves had not moved.

So far, I am very pleased with the results. I will check the valve lash again in about 2,000 miles.

[2LZ]

Originally Posted by SpudRider

Today I checked the valve lash with about 27,250 miles on the odometer. The exhaust valves had closed about .001 mm, and the intake valves had not moved.

So far, I am very pleased with the results. I will check the valve lash again in about 2,000 miles.

That's great news Spud!.....and sounds much more like my results. My intakes never seem to move, just the exhausts have closed up a little each time but I need to start putting on more miles now that the rain has finally stopped.

[MalcolmReynolds]

Spud, Have your remained stable after you did the rebuild? You should do a tutorial video series on how to do this stuff! Just awesome. For a person who is mechanically challenged it would be great to have someone that explains the what and how to do this kind of thing. Very impressive you can get the parts for this bike so affordably.

[2LZ]

Originally Posted by MalcolmReynolds

Spud, Have your remained stable after you did the rebuild? You should do a tutorial video series on how to do this stuff! Just awesome. For a person who is mechanically challenged it would be great to have someone that explains the what and how to do this kind of thing. Very impressive you can get the parts for this bike so affordably.

Just a heads-up. I haven't seen Spud around in quite a long time. He is truly a positive influence and wealth of information who's sorely missed.
From what I understand, he bought another bike and is involved with that now.
Others can chime in on what I'm lacking.

[jbfla]

Originally Posted by 2LZ

Just a heads-up. I haven't seen Spud around in quite a long time.
From what I understand, he bought another bike and is involved with that now.

I've seen Spud post on AdvRider....on the Versys X-300 thread.

I'd be curious about the fate of his RX3.

jb

[2LZ]

Originally Posted by jbfla

I'd be curious about the fate of his RX3.
jb

Same here. He was the Grand Poo-bah of the Cult of the Zong and probably their biggest cheerleader. He sold a lot of bikes for them.

[Cafetracer]

Originally Posted by SpudRider

Here are some additional photographs I took while the engine was apart.





Here is a closeup photograph of the valve recession.



CSC sent me a new cylinder head and new exhaust valves under warranty coverage.

Using my valve spring, compression tool, I installed four new valves in the new cylinder head. I lapped all four valves, and also installed four, new, valve stem seals.

After reassembling the engine, I re-installed the engine in the frame, and reassembled the motorcycle. As I posted earlier, the bike has now been running very well for over 3,000 miles, and all four valves are holding the correct clearance.

Hello! I'm new to the forum. I was just wondering where you ordered your valve seals? Thank you!

[ChopperCharles]

Is there a trick for getting the front cam chain guide in place?

I got a new head, did all the same work, and my engine sounds terrible. I followed all the steps exactly... but what I didn't check to see is if the bottom of the cam chain guide is supposed to fit in a notch or something. I just dropped it into the notches at the top.

Charles.

[ChopperCharles]

Just as an FYI for those of you contemplating this, it is not necessary to remove the rear wheel or swingarm. Put the bike on the center stand. Jam an old paperback under the rear wheel, to support it. Remove swingarm bolt. The rear end will not move.

Quick order of disassembly:

Unplug electrical connectors (stator, starter, ground, O2)
Unplug the two coolant hoses, draining your coolant in the process.
Remove the bolts that hold the intake manifold to the head
Remove the exhaust pipe
Remove the lower crash guards
Remove the cradle under the engine.
Engine now held on by swingarm bolt, one bolt on the cylinder head, and one more bolt at the rear.
Loosen chain and remove countershaft sprocket
Support the motor, remove those three bolts, then lower the motor to the floor.

It's actually really quick and easy to get the motor in and out. Probably the easiest of any bike I've ever done. I did remove the radiator wings but didn't remove the tank - just lifted it to get access to the wiring. No tire removal or swingarm removal.

Charles.