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Author Topic: Decarbonization, piston upgrade, drill case for old style breather  (Read 2163 times)

mattjohnson207

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Parked my '09 AVL several months ago due to hard starting, metallic top end noise, and constant kickback. 8,000 miles.  Need a laundry list...Want reliability above all.  I definitely want to drill out the case to go back to the old iron barrel style breather. ( for off road use only of course:)  I read the previous tread on piston/ cylinder specs...don't have that kind of expertise ...but want to upgrade piston  for my peace of mind, and anything else I may have overlooked. Was thinking  32 mm Amal mk1,or  TM32 mentioned in a recent thread. 
   Reliability and peace of mind is my main goal, not necessarily  performance.....
    Thanks,  Matt in Glendale

mattjohnson207

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #1 on: July 23, 2013, 05:05:23 AM »
Forgot...I also want to drill out the head and install an enfield decompression valve ,looks like a pretty simple installation ,  10 mm as opposed to the  larger Harley,  All I have are a hand drill and  tap, am I being too optomisic?  Searched Nfield gear for decomp valve...
« Last Edit: July 23, 2013, 05:39:58 AM by mattjohnson207 »

DanB

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #2 on: July 23, 2013, 02:09:56 PM »
Hi Matt,

Sounds like a good project, so please share progress and lots of pics!  Have you seen Adrian's decomp thread:  http://www.enfieldmotorcycles.com/forum/index.php/topic,16052.0.html

If you're out for reliability and are opening the case anyway, you should think about bearings / conrod as well. 
« Last Edit: July 23, 2013, 04:14:59 PM by Kevin Mahoney »
Suppose I were an idiot, and suppose I were a member of Congress; but I repeat myself. ... Mark Twain
2006 AVL Electra

ERC

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #3 on: July 23, 2013, 10:07:59 PM »
Don't know if you can put the old style breather on an AVL. Ace may know and would help you with it.  ERC
2-57 Apaches, 2-57 Trailblazers, 60 Chief, 65 Interceptor, 2004 Bullet, 612 Bullet chopped.

mattjohnson207

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #4 on: July 24, 2013, 03:30:09 AM »
Was looking at some of the old threads, not sure, but if the case doesn't have  the crescent shaped relief  or cut out for the breather, I'd get my Mikita grinder and 4" disc. And  shape out the 1/2" X  2"  X 5/16 crescent relief .  Hopefully?  Sounds like a great mod

Ice

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #5 on: July 24, 2013, 04:50:05 AM »
 Per factory service manual  for the AVL, piston to cylinder clearance is .08-.10mm (.003-.004in) when new and the service limit is 0.30mm (.012in)

 Those numbers sound pretty big but they diminish quite a bit as the piston expands.
 
 The AVL came standard with a forged steel conn rod, a roller bearing big end and an oil pump that flows a lot more oil than any iron barrel hi volume pump could ever hope for.

 I believe the pistons to be pretty decent as I don't ever remember hearing of one giving trouble.

 If I had an AVL the breather and the de-comp are about the only things I would change about the engine itself.

 The AVL had the full length breather lump ( but un-drilled ) on the left side of the crank case until '06. The '07 had a half length breather lump also un-drilled. 
 A drilled '07 lump would need a short hose nipple installed by either threading or pressing.
 The lump has been drilled with the engine intact and in place by one of our forum brothers and the how-to was covered in a thread here.

 Not sure if '08 and later had the lump. If they didn't, fitting a bolt on breather lump like the interceptors used should be pretty straight forward.

  As mentioned adding a de-comp to the head has been done and I like the idea too. I think it is a better system than the valve lift system.
Plenty of meat there to drill and tap not by coincidence but by design. AVL twin spark was a production model available in the Indian home market.

 As far as ancillary equipment goes I would de-restrict the exhaust to make it run cooler of course. Adding a spin on oil filter for better filtration would keep the oil cleaner and make the engine last longer. A thermostat controlled oil cooler wouldn't help the engine any but it would make me feel bettw for the two to four weeks a year it gets hot enough here to want one.

 Installing a low restriction air filter and exhaust along with a 30mm PWK really, really woke up brother Bill Harris's AVL based scrambler.
 His Bullet was always quicker and faster than mine.
Its also quicker than my son's free flow, re-jetted, higher compression trails kitted Bullet

 With the recent addition of a set of S cams it's even quicker than it was before and now pulls like a 441 Victor or thereabouts.

 
« Last Edit: July 24, 2013, 04:53:01 AM by Ice »
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

mattjohnson207

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #6 on: July 24, 2013, 08:58:22 AM »
My 09 AVL has a nub the size of a small grape where the breather will be drilled .  They say if you sit in an airplane cockpit long enough you'll think you can fly it.  Drill in place...not have to split the cases...not replace the piston...hmmm
   Thanks for Adrian's thread and photos
      Matt
Ps saw Aces thread oct 2 nod 2009.... Looks like I'm  going to have to use the Mikita and split the cases.  That crescent relief  allowing air flow around the sleeve might not be there. Will be a cheap mod though, just the engine gasket set...thanks
« Last Edit: July 24, 2013, 09:58:04 AM by mattjohnson207 »

D the D

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #7 on: July 24, 2013, 02:10:02 PM »
My 2007 Iron barrel has a little nub, but beware: that nub is the base of a threaded cylinder stud, not where the breather went.  The breather would have been below it.

'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH

Kevin Mahoney

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #8 on: July 24, 2013, 05:45:58 PM »
On average I think you are getting good advice from Ice. In the real work the AVL has turned out to be a good engine. It cools a lot better than the iron barrel, has a better crank and bearings, and oiling system as mentioned. The pistons are good, we had some initial head gasket failures but that seems to have settled down.

The breather leaves something to be desired also as mentioned.
As for an oil cooler I think you should put a thermometer in your oil tank after a good ride. I think you will be surprised, especially with that engine. It runs cooler than you might think. 

Ice

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #9 on: July 25, 2013, 05:48:36 AM »
My 2007 Iron barrel has a little nub, but beware: that nub is the base of a threaded cylinder stud, not where the breather went.  The breather would have been below it.

Thanks Br. D the D, I love a mystery!
 
The 64 dollar question.
 When was the lump deleted ? early middle or late '07 ?
 Fellows, please check your engine numbers and let us know the month it was made and if it's lump or no lump.

First digit denotes the year I.E. 6=2006
Last character should be a letter for the production month A= January, H= August, K= September, N= December


« Last Edit: July 25, 2013, 05:53:24 AM by Ice »
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

D the D

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #10 on: July 25, 2013, 02:59:54 PM »
Ice,
All I can tell you is that my 2007 Iron doesn't have the lump nor the crescent cut inside.  I remember someone else here had a 2007 that had a partial lump and the cut inside.  Ace posted that he's seen 2007s with them.  My date is Feb?  I'll have to check.  Doesn't seem to be rhyme or reason for a cutoff date.  You have to pull the barrel and check for the crescent unless someone knows for sure that the AVL didn't have them.
Good Luck!  I hope you have them.
Dennis
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH

Ice

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #11 on: July 26, 2013, 06:20:49 AM »
Mines an '06 with the full lump ( un drilled ) Brother Bill Harris's AVL also an '06 came with the lump.
I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

D the D

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #12 on: July 26, 2013, 06:36:39 AM »
March '07 and no lump, no internal crescent.
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH

mattjohnson207

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #13 on: July 26, 2013, 07:17:18 PM »
Thank you all for your encouragement.  Took the head off this morning , easily. The two rocker arm studs came off with it; normal?
        Stuck on the barrel though, hit a protruding  solid part with  hammer and chisel ...nothing.  Figured I'd better wait for advice.
         Pictures tomarrow , work night shift...too tired.
          Again, thanks for all your help
                       Matt

D the D

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Re: Decarbonization, piston upgrade, drill case for old style breather
« Reply #14 on: July 27, 2013, 01:49:31 AM »
Not 100% sure about an AVL.  Someone will let you know.
On an Iron Barrel you need to remove a nut on a stud holding the barrel to the case above the tappet cover.  Also, loosen the two cross bolts holding the case together closest to the barrel.  They clamp down on the barrel.  It should pop right off after that.
'07 Iron Barrel Military (Deceased 14 September, 2013)
2014 Yamaha Bolt R Spec V-Twin
1975 XLCH