| Author |
Message |
    
Barrick09
| | Posted on Wednesday, March 12, 2014 - 10:46 pm: | 
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Rocket - I forgot to mention that it does have an aftermarket Dyna S Ignition. So i Will make sure to check the timing on rebuild. |
Phelan
| | Posted on Wednesday, March 12, 2014 - 10:47 pm: |
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I can't comment on the damage, but I will say to ALWAYS shut off the fuel valve when the bike is off. I worked on my brother's FXD that sat for a a couple years, only ran for a short while every couple of weeks, and there was over a gallon of gas in the oil from gas seeping through the carb, past the rings and into the oil sump. |
Lynrd
| | Posted on Wednesday, March 12, 2014 - 10:49 pm: |
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Dyna S - That is the one with the flyweights, right? So no VOES...
You might want to forget what I said about using the rev limiter for a shift indicator...you don't have one... |
Barrick09
| | Posted on Wednesday, March 12, 2014 - 11:08 pm: |
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WAIT!! I do  I have a Dyna rev limiter to! |
Screamer
| | Posted on Thursday, March 13, 2014 - 08:51 am: |
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"never seen anyone just plug their breather before"
I have seen two situations where the crankcase system had no vent to atmosphere (unintentionally). One was an aftermarket air cleaner with mis-manufactured breather bolts (no breather hole), and the other was a customer that assembled miscellaneous parts for home-built air cleaner kit. The symptoms on both that brought the customers to the dealership was a "pushed out" rocker box seal.
Plugging the breather system will create issues. I still suspect the blown head gasket shown was due to other problems. |
1313
| | Posted on Thursday, March 13, 2014 - 09:09 pm: |
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I have seen two situations where the crankcase system had no vent to atmosphere (unintentionally).
I have rather close experience with one instance of blocked breathers. A certain '99 M2 owner accused my S2 of throwing oil at his gas tank. When I inspected his bike, both breather hoses were kinked which pushed tranny fluid up his clutch cable and out onto his tank.
I'd have to side with R. on this.
suspect the blown head gasket shown was due to other problems.
Blocked breathers would give some other, less serious, causes of concern - at least initially.
Just my $0.02,
1313 |
Rocket_in_uk
| | Posted on Thursday, March 13, 2014 - 11:36 pm: |
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The head gasket failure shown in the photo appears to be between the two left cylinder studs (a common location). The drain holes are between left side cylinder studs and the right side cylinder studs - favoring the right side. The gasket does not appear to have failed in that area. The area on either side of a cylinder stud has higher clamp-load and typically will not leak cylinder pressure - most head gasket failures occur (left side) centered between the cylinder studs where the clamp load is lower.
Sorry but I don't agree. The clamping pressure is a constant across the surface of the gasket, or designed to be so within the working parameters of the engine. Obviously if a failure were to occur it's not that the clamping pressure is less between the studs. It's simply a case of excess pressure / cylinder seal failure, will find the least resistant path, which won't be close to the studs, but between them. BUT DON'T BE CONFUSED. THIS IS NOT WHAT'S GOING ON.
If any reason could be attributed to the failure of the gasket being common place in that area it's most likely due to the spark plug location amplifying a hot spot brought about through detonation.
I say this because it's likely another clue to why the gasket has failed in this location, but not a given. Such could not be determined until the head is pulled. There are several other reasons why a hot spot, or just a gasket failure itself, could occur at this location.
It's still likely though, if head gasket failures are commonplace on other (many) Evo engines in this location, it's not clamping pressure that's to blame. It would be localised excess temperatures concentrated about the plug burn as this is the start of the flame front, therefore the gasket is under more duress closer to the initial flame front when hot spots occur that are related to burn ignited by spark.
Crank case pressures should have little impact on head gasket durability. There are many less durable paths (than the head gasket) for excess crankcase pressure to force it's way out. Plus the head gasket has minimal exposure to crankcase pressure through the drain holes. A head-to-cylinder joint can leak oil at the drain hole area of the gasket but is unlikely to "blow out" leading to a loss of chamber pressure.
Indeed. It's clearly NOT a cause brought about due to excess crankcase pressure. I don't see anything wrong, in breathing terms, with the breathing system in the pics. Hoot's idea is one I'd be going for also with the set-up in the pics.
Rocket in England |
Screamer
| | Posted on Friday, March 14, 2014 - 10:15 am: |
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Rocket - no apologies needed for disagreeing. Thanks for the input.
I'm not confused - my reason for joining in was that it seemed to be implied that the problem would be solved by improving the breather system. My concern was that Barrick's engine would be reassembled without determining the root cause for the head gasket failure. Regarding clamp load- I've had and I've witnessed others having struggles with unequal clamp load issues on XL Buell heads especially in "high chamber pressure" engines. |
Barrick09
| | Posted on Friday, March 14, 2014 - 10:36 am: |
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So sorry for the late reply. Talked to my mechanic yesterday. He said he used James gaskets?
I am going to do the rebuild myself this time. It's just to cold here to start on it, 16 degrees in my garage.
Couple of thoughts. I'm thinking about going with a thicker gasket to reduce compression. I will have to do this on front and rear tho. Any thoughts?
Also he mentioned prepping the surfaces were they are scuffed in a way to better give the gasket traction/tooth to hold on too.
Will let you know/get pics when I get the heads of te front.
Thanks. |
Bluzm2
| | Posted on Friday, March 14, 2014 - 11:23 am: |
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Test the compression on the good cylinder before you start the tear down. This will give an idea for your starting point before you start changing compression ratio and such.
Quick 5 minute test... |
Sportyeric
| | Posted on Friday, March 14, 2014 - 12:05 pm: |
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Or measure the volume of the combustion chamber. Should be 67cc, IIRC.
A thicker gasket is the wrong thing to do. Read up on setting squish area. If you're going to do the work yourself, you might as well improve on the set-up.
(Message edited by Sportyeric on March 14, 2014) |
Kalali
| | Posted on Friday, March 14, 2014 - 02:50 pm: |
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You're putting the cart before the horse. You need to first find out the root cause of the issue and then find the right solution. Just putting a thicker gasket is definitely the wrong thing to do. Take your time and take good measurements before and as you take things apart so you can compare with the OEM dimensions. |
Rocket_in_uk
| | Posted on Friday, March 14, 2014 - 06:55 pm: |
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Screamer, apologies as I didn't mean you were confused. Nor was I wanting to appear like a 'no it all'. I am far from such in these matters. I was just saying, no one should be confused by what's going on here in relation to you mentioning clamping issues and what's likely going to turn out to be a detonation issue.
I'm not familiar personally with high output XL engines and clamping pressure failures, but in ANY higher output tuned application, when working outside of the original intended design parameters of an engine, I don't doubt clamping load becomes a consideration. You raised a good point in my opinion, which brought about a more concise explanation from me. I might well be proven wrong too!
Rocket in England |
Rocket_in_uk
| | Posted on Friday, March 14, 2014 - 06:59 pm: |
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Give me time. I will copy Denish's formula for checking / measuring mechanical compression.
It's simple to follow and what you need to do rather than as others have said, not to just use a thicker gasket. You have to get it right. Love the cart before the horse thing. We've all been there at some point, lol.
Rocket in England |
Barrick09
| | Posted on Monday, April 28, 2014 - 09:12 pm: |
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UPDATE!!
So it is finally warm enough that I started to dissemble the front cylinder But now I need some advice/help.
I have removed everything and I am down to what i believe to be the last 6 bolts to remove the head. These being the 4 studs that hold the cylinder together and the 2 that mount the head to the frame.
When I remove the 2 bolts that mount it to the frame how much will the engine drop? Any recommendations on the best way to secure this engine after these are removed and removing the top of the head?
Thanks in advance. Also as an update everything looks good so far, however one of the threaded plugs for the lines for the carb into the top of the cylinder was broken in half. pics soon! |
Jim2
| | Posted on Tuesday, April 29, 2014 - 08:47 pm: |
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I used a floor jack under the front shock mount. I left it there until work was complete and the front mount was back on. I had front wheel secured in chock with two tie straps from forks to chock. Back was off ground using rear passenger pegs (M2) flipped upside down on jack stands. |
Barrick09
| | Posted on Wednesday, April 30, 2014 - 07:01 pm: |
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Thanks Jim, I wasn't even't sure anyone would see my post the thread was so old.
How far will the engine drop out when the bolts are removed? I want to make sure I don't go to far as to hurt something/bend something.
Thanks for the advice. |
Jim2
| | Posted on Friday, May 02, 2014 - 10:55 am: |
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The way it works is the jack under the front supports it at the same height it is already at. When the bolts come out it doesn't drop at all. The jack must stay under undisturbed until your ready to put the front mount back onto the newly installed front cylinder. |
