[fledermaus]

I have been reading this forum for quite some time.  And it has taught me much about the Royal Enfield.  I was hoping my first post would be that I made it to 10,000 miles without a hitch. Alas it is not so.

The particulars. RE 2012 Military.  Broke in gently, ridden spiritedly afterwards.  Minimal vibration. Mostly stock (aftermarket exhaust after the original suffered cracked welds)

Riding along a state highway in excess of 65 MPH the engine suffered complete loss of power.  I roll to a stop and nothing I tried (from the dozens of tricks learned here) would get the engine running again.

Rolled into the carport and pulled the head. Intake valve looks like it departed the keepers (keepers are still in the spring) and thwacked the piston.  Piston has a pretty nice moon divot in the top.

Questions:

1.  Can I keep the head and swap out valve and seat?  No damage other than bent valve is seen.

2.  Can I just dress the ding on the piston top?  Smooth it out to avoid detonation.

3.  If not 1. and 2. what are my best options?

Photos to follow.

[fledermaus]

Please have a look...

[ace.cafe]

Please have a look...

You were very lucky that much more damage wasn't done.
You needs a new valve and a valve seat grind to mate the new valve.
You might be able the keep the piston, but it is damaged,  and we are not sure that something wasn't damaged down below.
I would suggest at least having a look at the rest of the piston to check it out.

[fledermaus]

Thank you.  I was hoping I could get away with just a valve, guide and retainers.

Valve stem actually has an S-curve to it.

[ace.cafe]

Thank you.  I was hoping I could get away with just a valve, guide and retainers.

Valve stem actually has an S-curve to it.

You may need the guide too.

[Arizoni]

I think if you intend to keep on with your "spirited riding" you should plan on replacing the valve and lapping it in and replacing the piston.

If you can stand to change your riding to a more sedate style, you could probably get away with just buying a valve and lapping it in.
The notch in the head should be carefully smoothed out and blended in to remove any nicks.  Nicks form stress risers that will eventually turn into cracks.

As I said, this fix would only be suitable for gentle riding because just removing the nick will still leave the head of the piston thinner and weaker.

[fledermaus]

Good advice...  I will try blending in the nick.  I figures the valve and the guide were goners as the valve had to be hammered out.

Any suggestions on vendors and/or kits?

[no bs]

this sure sounds familiar... try the cmw store in ft.worth, but call them, it's easier than looking for parts on the website.

[gashousegorilla]

 VERY LUCKY !   And very odd ?    Both keepers  and the retainer where still in place ?     How do the keepers and the groove at the top of the valve stem look ?   Did you measure the valve stem ?  Particularly  up near that groove ?   You should see something very near to 7mm.

  I would also take a close look at your Rocker block/ Rocker bearing.... which ever you prefer to call it.  In those rocker blocks, there are oil passages . Oil enters from the under side of them , lubricates the rocker arm shaft.  AND on either side of the blocks, there are two oil squirter's  .... two little holes.  One points at the pushrod tip side of the rocker arm.  And ..THE OTHER ONE... points at the  top of the valve stem tip, on the spring side of the rocker arm.    IF.. that valve/ spring side oil squirter is blocked or mis-directed ?   You would have no oil lubrication at the tip of the valve, in the area of the keeper and retainer to cool things down there.  ... Oil pools WELL below in the valve pocket and would provide no real splash lubrication and cooling at that valve tip area. So those oil squirter's are important to have open.     I would blow out all those passages to be sure.


  I would also make sure that the oil passage from behind the right side cover, through the cylinder and up into the head is clear.   Blow it out and make sure you are getting air coming out into the head.

[suitcasejefferson]

Yes, very lucky. It could have easily knocked a hole in the piston, let metal fall down into the crankcase, and possibly even bent the rod. I think I would replace the piston. I have no idea how thick the piston is, or the quality of metal it is made out of.

I did make it past 10,000 miles. Not without some issues, but nothing with the engine. It still runs great. I also replaced the long heavy cat con muffler with a much smaller, lighter, and louder one with a similar look. And, I replaced the EFI with an Amal carb. I'm so glad that was possible, not to mention cheap and easy, because I am not a fan of EFI.

I don't ride mine in a "spirited" manner, it has never been above 60 mph, and most of the time I ride it at 55 mph. I like to take it out on the highway and ride it 200 miles or more at a steady 55. It is a very relaxing ride. The seats in many expensive cars now come with built in vibrators. Not necessary on the RE. And the sound of the long stroke single at low rpm through a less restrictive exhaust is pure music.

[fledermaus]

VERY LUCKY !   And very odd ?    Both keepers  and the retainer where still in place ?     How do the keepers and the groove at the top of the valve stem look ?   Did you measure the valve stem ?  Particularly  up near that groove ?   You should see something very near to 7mm.

  I would also take a close look at your Rocker block/ Rocker bearing.... which ever you prefer to call it.  In those rocker blocks, there are oil passages . Oil enters from the under side of them , lubricates the rocker arm shaft.  AND on either side of the blocks, there are two oil squirter's  .... two little holes.  One points at the pushrod tip side of the rocker arm.  And ..THE OTHER ONE... points at the  top of the valve stem tip, on the spring side of the rocker arm.    IF.. that valve/ spring side oil squirter is blocked or mis-directed ?   You would have no oil lubrication at the tip of the valve, in the area of the keeper and retainer to cool things down there.  ... Oil pools WELL below in the valve pocket and would provide no real splash lubrication and cooling at that valve tip area. So those oil squirter's are important to have open.     I would blow out all those passages to be sure.


  I would also make sure that the oil passage from behind the right side cover, through the cylinder and up into the head is clear.   Blow it out and make sure you are getting air coming out into the head.

Valve stem looks good (except for S-curve in stem) keeper slot looks good.

The keepers on the other hand are practically smooth on the inside.  One has little indication of the ridge that is supposed to keep the stem in place. The other only a slight rise where the ridge should be.   It appears it is the keepers just let go.

Oil passages appear clean and unobstructed.

Are the keepers a known issue?

[fledermaus]

Yes, very lucky. It could have easily knocked a hole in the piston, let metal fall down into the crankcase, and possibly even bent the rod. I think I would replace the piston. I have no idea how thick the piston is, or the quality of metal it is made out of.

I did make it past 10,000 miles. Not without some issues, but nothing with the engine. It still runs great. I also replaced the long heavy cat con muffler with a much smaller, lighter, and louder one with a similar look. And, I replaced the EFI with an Amal carb. I'm so glad that was possible, not to mention cheap and easy, because I am not a fan of EFI.

I don't ride mine in a "spirited" manner, it has never been above 60 mph, and most of the time I ride it at 55 mph. I like to take it out on the highway and ride it 200 miles or more at a steady 55. It is a very relaxing ride. The seats in many expensive cars now come with built in vibrators. Not necessary on the RE. And the sound of the long stroke single at low rpm through a less restrictive exhaust is pure music.

My riding was a combination of 90% safe and sane and 10% ride it like you stole it.

My vibration was minimal compared with a Yamaha 650 and a thrashed XV920R...  Only thing vibrated loose in 6,000+ miles was the welds on the exhaust.  Now it breather through a basic straight through with minimal baffling.

Music indeed to stir the soul.

[gashousegorilla]

Valve stem looks good (except for S-curve in stem) keeper slot looks good.

The keepers on the other hand are practically smooth on the inside.  One has little indication of the ridge that is supposed to keep the stem in place. The other only a slight rise where the ridge should be.   It appears it is the keepers just let go.

Oil passages appear clean and unobstructed.

Are the keepers a known issue?

  No... no they are not.  At least not to my knowledge.  The ones that I have seen looked pretty good.  Interesting ?   Those valves are stainless and those keeper's are hardened steel.   Maybe they were soft ?   Or Unfinished shallow ridges  from the factory ?   6000 Miles ain't a lot  I tell ya.  And you certainly didn't abuse the bike.   This nonsense about you can't ride over  55-60 mph on these motor's , is just simply not what I have found.   Plenty of people do , including myself and do it regularly and over long distances.  I have been in side these motor's and try not to make assumptions about them.. They are quite capable from what I have seen.  and I do not park my bike in my living room from fear of riding it.     

  Of course you cant go over 55 mph if something is wrong or defective on an INDIVIDUAL motor.   We can probably count the engines failures that we have seen here on the forum on one hand , in these last 8 years?

Anyways.... I would replace those springs too.  The spring may be weak as well and lost control of the valve, hammering those keepers smooth.

[Kevin Mahoney]

The UCE engine can take a lot of abuse as far as speed goes. The Iron Barrel is an entirely different matter. You are lucky about this. I don't think I ever did a warranty claim for a failure of this type. I remember one where the head of the valve dropped off but not this. Thankfully it will be an inexpensive repair. You are getting good advice that is not "over thought", go with it. I also agree call RE of Ft. Worth at1 (817) 834-1392 for parts. They can usually have them ready to ship in a day or two. Website is better for accessories, calling is the way to go.

[johno]

totally agree with the strength of the UCE engine.
I ride regular 100 plus miles 50 miles of which is on fast dual lane roads at 65-75mph without any problems so far with the engine...nuts and bolts on the B5 on the other hand, well!!!
I think you are just plain unlucky with an end of week built bike.....