Broken Intake Rocker Arm, Any Suggestions?

7 replies to this topic
  • SonOfCombustion

Posted October 08, 2006 - 02:57 PM


Ok, what I know...
I got a 2001 R, 2 months and 1100 miles ago
The bike started ticking ~ 400 miles ago
I adjusted the valves 300 miles ago and the int. were ~ 1/16" off
I changed the oil (I use dino) when I adjusted the valves, oil level was fine
Coming home Weds my bike lost a lot of power and started ticking
The Intake rocker had broken off 3/4" of an inch from the camshaft end.
The exhaust rockers are heavily worn (gall'ed) on the camshaft end
The cam APPEARS fine, and does not have any abnormal wear on it.
The top of intake valves are bashed in from the tappets traveling so far before making contact with them.

What I don't know...
When the previous owner changed the oil
If a previous owner ran the oil dry
If this was an abused bike
If I damaged anything other than what I can see

What I believe...
Since my Intake needed so much adjustment the first time I checked it, this problem started LONG ago, when a previous owner ran it dry, causing the hardened metal on the outside of the surface of the rocker to wear, exposing the softer metal on the inside to accelated wear. Finally enough material wore off that the rocker just gave up. Of course, it could all be my fault by not changing the oil when I first got it. And as my father (InternalCombustion) keeps telling me, I need to put synthetic in it.

Anyway, this is what I need, and if anybody has any of these lying around their garage, I would love to buy them from you. Also, if you can think of anything else I need to be checking, please let me know.

1 Original Cam (this is my commuter, so a hot cam isn't necessary)
2 intake valves
1 intake rocker arm
1 left exhaust rocker arm
1 right exhaust rocker arm

Pictures can be seen at:
then click on the "rocker arms" folder


  • SonOfCombustion

Posted October 08, 2006 - 03:12 PM


One more note...
This bike got me home 18 miles, AFTER this rocker broke.
Gotta give credit where credit is due.


  • Old_Man_Time

Posted October 09, 2006 - 10:52 AM


So are you thinking the rockers were actually sticking on the rocker shaft creating a resistance that snapped the rocker? Was there any sign of that on the rocker shaft. What about the threads on the tappet adjuster screw and it's hole? It seems like you were getting too much play almost like the threads were bad and the adjusting screw was backing out. But you would have noticed that when you went to remove the lock nut on the tappet adjuster. Valves generally stretch which causes them to tighten up not loosen up. The condition of the tappet face seems to indicate a hammering condition caused by the rockers seizing on the rocker shaft or the tappet coming loose and being ridden while it was way loose.

Sounds like a head job. I hope your valve guides and seats are OK but most likely not worth taking a chance on. Have you seen the top of the piston yet?

I don't have any spare parts myself. I have a stock cam with no miles on it but I have been saving it cause we are starting to get regulated for sound. My Stage 1 cam will not run right with the Baja Designs baffle but the stock one will.

How soon you want to ride your bike? Waiting for E-bay to come up with spare parts may be a long wait.

  • cleonard

Posted October 09, 2006 - 11:07 AM


I think your analysis is correct. A lack of oil caused the root of the problem.

There has got to be a lot of metal bits floating around. While I don't have a 650R, I'm pretty sure that there are 2 metal screens. One is at the bottom of the frame oil tank, and the other is under the right crankcase cover.

Take a look and make sure there is no restrictions in the oil passageways.

On my 600, there is an external oil supply line that goes to the head. After any engine work, I always check that oil is getting to the head. After it has been running for a minute, I loosen the fitting going into the head. Oil should come out. It's scary how long it takes the oil system to prime on a rebuild. Next time I will fill the oil filter area to cut the time down some.

About the only used part that you are likely to find is the cam. You might even get one for shipping. I'd start another thread titled "Stock 650R cam wanted" or something. There must be a lot of them sitting around after an upgrade. For the rest, Service Honda has about the best price.

Take a real close look at everything. Give the rocker shafts a real close look. If there is any wear at all, I would replace them too.

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  • Huffa 2

Posted October 10, 2006 - 04:06 AM


So what's the verdict, are you going to buy new? I don't think it's even a good idea to buy those type of parts used unless you know for sure the history of them.

You might want to give Ron Hamp a email or call and see if he has connections with anyone that may have those parts.


He is very well known on TT and works on the CRF's a lot motor wise but he may be able to steer you in the right direction for used parts or have some suggestions on what "hardware" (type valves) to use .

He did my head pertaining to the valves, seats, and guides.

  • Boston Mangler

Posted October 10, 2006 - 04:38 AM


Ya might wanna check eBay for parts. There was a guy parting out an 650R engine on there last week.

  • SonOfCombustion

Posted February 25, 2007 - 02:28 PM


Here's an Update...
Ok, I replaced all of the stuff shortly after this post was started. I went 300 miles down the road and valve noise pointed out that it was happening again. So, after about 74 beers and 2 months trying to pinpoint the problem, I JUST saw what might have been causing it...

When I replaced the cam, I followed page 8-19 (Camshaft Installation) in the manual, where it says "The outer bearing rubber shield faces outside" well, I didn't know what the "outside" was, and the picture showed the non-chain side, so that's where I put that rubber shield'ed bearing. HOWEVER... if I would have noticed on 8-20, the "outside" of the cam is the chain side. So I just went outside to double-check, and low and behold, that was causing all of the oil destined for the cam lobes to drip down the cam chain.

Now, I don't know if this is what caused it the first time, as I don't know how the cam was assembled from the prev owner, but I hope this will prevent others from having this happen if they replace their cam.

Hmm, should I drink another beer in victory, or drink another beer because I ripped the entire engine apart looking for clogged oil passages, causing my bike to be down for the past 2 months? Either way...

  • SonOfCombustion

Posted February 26, 2007 - 06:53 AM


Forgot to note...
In my disassembly, I found that the oil hose from the BOTTOM of the frame into the oil pump had some stuff that can best be described as snot in it.
It was opaque and runny, and came out with medium pressure from me blowing through it. I don't THINK that this was causing oil starvation, as it would mean that the frame would be filling up with oil, and I did not notice that. Just an interesting observation.

I have NO idea what it was, but I cleaned it all out with carb cleaner. I did not notice it anywhere else in the engine/frame.

If anybody knows that this means the end of the world, or that my rear tire has low air pressure in it, please let me know.


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