Author |
Message |
Barrick09
| Posted on Wednesday, September 13, 2017 - 03:48 pm: |
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Hello Everyone. I was hoping to get some opinions on a reoccurring problem I am having with my 99 X1. I've owned the bike about 7 years and in that time I have blown 4 head gaskets in this order rear, rear, front, and now rear again. Generally anywhere from 1.5-2 years between blow outs. Always professionally done, heads machines, new hardware ect. I'm not concerned with the assembly as I think the problem may be something else. It always happens without warning and always on start up. Pretty much when you press the button you head a loud bank and the gaskets gone. Normally the bike fires right up with no hesitation and goes straight to idle and runs great. I am suspect of this carb/breather set up on the bike. It has a Mukuni Carb and the breather lines run between the cylinders to a filter and hose. (see pictures). This is how its always been but is it correct? problematic? concerning to anyone? Could excess fuel be leaking into the cylinder causing the blow out on start up? Could a clogged breather system cause built up pressure? Prior to blow out cylinders have no leaking on base gasket, head gasket, or rockers. Any suggestions to prevent this again or is this just simply Harley. Thanks. Top view of Carb
Lines going down between Cylinders
Lines from other side with T joint and filter.
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Barrick09
| Posted on Wednesday, September 13, 2017 - 03:50 pm: |
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As an addition I believe the bike has a Dana S ignition but I don't really know much about that it. In case it has something to do with ignition on start up. |
Natexlh1000
| Posted on Wednesday, September 13, 2017 - 04:34 pm: |
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If the breather was under a great deal of pressure, I think it would be much more likely to pop the oil tank lid first. |
Hootowl
| Posted on Wednesday, September 13, 2017 - 04:59 pm: |
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The return oil is pumped to the tank. It does pump air, as the rate of return is greater than the rate of supply, so as to keep the sump pumped out. The tank has to have a way to deal with this excess air. I doubt a little bit of crankcase pressure is going to make the dipstick pop out any more than the air being pumped into the tank will. If course, I could be wrong. And yes, excessive crankcase pressure can cause gasket failure. Not head gaskets though. Those deal with combustion pressure. Crankcase pressure is nothing compared to that. |
Barrick09
| Posted on Wednesday, September 13, 2017 - 06:43 pm: |
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What are everyone's thought on turning the gas off while its parked? I've heard mixed opinions about that as well. |
Two_seasons
| Posted on Wednesday, September 13, 2017 - 07:14 pm: |
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On carb'ed bikes, the petcock is ALWAYS shut off when engine is off. Always. |
Upthemaiden
| Posted on Wednesday, September 13, 2017 - 08:10 pm: |
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I agree, always turn the gas off. Should just be part of your normal key/kill switch/choke routine. |
Ratbuell
| Posted on Wednesday, September 13, 2017 - 11:13 pm: |
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And leave the carb bowl full. Air is what spoils fuel; a "dry" carb bowl will clog up much faster than a full one. Just turn off the valve so the pressure of the fuel in the tank isn't pushing on the float. As to your issue - have you looked at the blown gaskets? Are they popping in the same location each time? A pop (backfire?) sounds to me like intake leak, or jetting issue, or timing. Not breather. But if the gaskets blow in the same place every time, that tells me a mechanical sealing issue is going on. |
Lynrd
| Posted on Thursday, September 14, 2017 - 08:32 am: |
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On my bike, half the time the gas is still off when I start riding. Then I remember shortly after that. |
Barrick09
| Posted on Thursday, September 14, 2017 - 10:26 am: |
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The Gaskets do not blow at the same location. Been a different spot almost everytime. Currently I am not sure what size jets are in the carb but I will check. What is the best way to check for an intake leak? Wouldn't I notice a problem at idle or while riding if the timing is off? I guess if its only off by a couple degrees it would run fine but have prolonged damage. |
Phelan
| Posted on Thursday, September 14, 2017 - 10:40 am: |
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Do you have any pictures of the blown gaskets? What kind of gaskets are you using? And have you checked the decks on the heads and cylinders for damage before installing the new gaskets? Are you running the gaskets with O-rings? Old gaskets used O-rings around the dowels, but most new gaskets do not. If you ran an old style gasket without, or a new style with, that will always cause a failure. |
Barrick09
| Posted on Thursday, September 14, 2017 - 11:11 am: |
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Phelan - Gasket is blown on the right side of the rear cylinder between the pushrods. I have not taken the engine apart yet. I am using the cosmetic gasket which everyone recommends, NO O-Ring. Yes the Cylinders and head were always checked for damage/warping/surface finish before installing. When needed they were machined. I've done some research on the intake leak and I think it's very possible I might have one. Once I pull the carb today I should know better. Once its back together I'll take it to get the timing and carb adjusted since this has never been done. Any thoughts on using a gasket spray like Permatex Copper Spray? I've seen this done before. If it can't hurt then it might help. If not then its nothing lost. |
Phelan
| Posted on Thursday, September 14, 2017 - 11:55 am: |
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I like the Copper spray and use it on metal gaskets often. |
Williamscottrobertson
| Posted on Thursday, September 14, 2017 - 02:56 pm: |
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I bought a cometic gasket kit and it came with o-rings and the multi layer rubber coated head gaskets. Since I pulled o-rings off my s2 (with fiber gaskets) so I put them back on in assembly. Did I boo boo using both? No head gasket failure yet. |
Williamscottrobertson
| Posted on Thursday, September 14, 2017 - 02:57 pm: |
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The metal gaskets had a little "raised" area where the o-ring went. |
Odd
| Posted on Thursday, September 14, 2017 - 08:24 pm: |
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not saying this it but I have seen this problem when the heads are assembled and there was no oil put on the cyl. studs and not enough oil put under the head bolts |
Barrick09
| Posted on Thursday, September 14, 2017 - 09:40 pm: |
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I can't say for the rear as I did not assemble it last time but the front head had oil under the cap and threads, but not as much as to hydrolock them. So far disassembly is going...well it's going almost to smooth. I removed the tank cover, tank, carb, cross over pipe (which had the bolts nearly snug) engine mount, rocker boxes, all the exhaust and that only took about 45 min! Hoping this isn't the calm before the storm. Tomorrow I'll get the jack under it and remove the head. I'll post pics once I'm there. |
Barrick09
| Posted on Thursday, September 21, 2017 - 12:47 pm: |
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Can anyone tell me the proper break in procedure for head gaskets? I googled it and holy crap does everyone seem to have a different opinion! Also I used the Permatex copper spray this time and WOW that stuff is like sticky glue for head gaskets! UPDATE: I removed the rear head and compared to the front the rear bolts were considerably more loose. I also found O-rings on the rear gasket. So much for "professionally rebuilt". Not sure if this was the cause as the rear was rebuild something like 4 year years ago. One thing that was a pleasant surprise was how clean the spark plugs and overall the tops of the pistons. Almost no carbon build up. I could practically wipe it shinny with a rag. Overall the entire tear down and build up took about 8 hours. Would have been 7 but I put the head on without the pushrod tube and removing the push rod retainers on the bottom took about an hour! |