kingster1 Posted February 17, 2017 Report Share Posted February 17, 2017 Im glad i have found this forum, i need some 2 stroke 101! I'm very good with 4 strokes, I rebuilt those on a daily basis. I'm having trouble with this 2 stroke banshee. I'm going to tell you what has happened and what I have done and maybe you can help me or point me in the correct direction. Once upon a time, I had a banshee come in for repair. It was leaking from the overflow and had spooge with the bottom end bog. I adjust floats, and still get smoke and spooge. Well I know spooge is leftover fuel that the chamber didn't burn. I then check the jetting, it have 25 for pilot and 280 for main. Although the main is a huge jump from stock, the bike has fmf pipes and k&n filter with the lid cut in half. My first instinct is not to toy with the jetting just yet because as we all know a 2 stroke that is starving for fuel or running lean will lock up, due to lack of cooling. I then go on to change the clip on the needle jet. That made a difference, it was actually rideable. It still had the bottom end bog, but once it hit the power band it would haul A**. My next thought is we may need to take it to the dirt and open it up, and burn all that spooge out. I was totally wrong. What happened next is the spark plug porcelain engraved a hole in the piston on the right side. Well without a doubt we had to purchase a top end kit. Where I purchased it from, ebay! was that the best decision probably not. I go on to install the new top end cleaning all old gasket material off and torqueing the head bolts in the number order. The banshee comes back to life, but still smokes like crazy and spits spooge. I can feel raw fuel on the back where the pipe meets the exhaust. Although it smoked the compression was at 115 psi in both. it was consistent. Well this sequence happened about a month ago. Today I go back to diagnose it and it wouldn't start. I check my compression again and its a 60 psi in both cylinders. What the f*ck? The carbs were completely off when I was performing this test. What could have caused this? failure of break in process? The bike has not been ridden at all since the rebuild. Also the reed seem to be in correct order also when I checked them. I'm lost for words on this one. I'm in need of help really bad. Quote Link to comment Share on other sites More sharing options...
Offroadman72 Posted February 17, 2017 Report Share Posted February 17, 2017 Im glad i have found this forum, i need some 2 stroke 101! I'm very good with 4 strokes, I rebuilt those on a daily basis. I'm having trouble with this 2 stroke banshee. I'm going to tell you what has happened and what I have done and maybe you can help me or point me in the correct direction. Once upon a time, I had a banshee come in for repair. It was leaking from the overflow and had spooge with the bottom end bog. I adjust floats, and still get smoke and spooge. Well I know spooge is leftover fuel that the chamber didn't burn. I then check the jetting, it have 25 for pilot and 280 for main. Although the main is a huge jump from stock, the bike has fmf pipes and k&n filter with the lid cut in half. My first instinct is not to toy with the jetting just yet because as we all know a 2 stroke that is starving for fuel or running lean will lock up, due to lack of cooling. I then go on to change the clip on the needle jet. That made a difference, it was actually rideable. It still had the bottom end bog, but once it hit the power band it would haul A**. My next thought is we may need to take it to the dirt and open it up, and burn all that spooge out. I was totally wrong. What happened next is the spark plug porcelain engraved a hole in the piston on the right side. Well without a doubt we had to purchase a top end kit. Where I purchased it from, ebay! was that the best decision probably not. I go on to install the new top end cleaning all old gasket material off and torqueing the head bolts in the number order. The banshee comes back to life, but still smokes like crazy and spits spooge. I can feel raw fuel on the back where the pipe meets the exhaust. Although it smoked the compression was at 115 psi in both. it was consistent. Well this sequence happened about a month ago. Today I go back to diagnose it and it wouldn't start. I check my compression again and its a 60 psi in both cylinders. What the f*ck? The carbs were completely off when I was performing this test. What could have caused this? failure of break in process? The bike has not been ridden at all since the rebuild. Also the reed seem to be in correct order also when I checked them. I'm lost for words on this one. I'm in need of help really bad. BAD CRANK SEALS WILL GIVE YOU POOR COMPRESSION!! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted February 17, 2017 Report Share Posted February 17, 2017 Leak down test? Sent from my SM-S820L using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted February 17, 2017 Report Share Posted February 17, 2017 Try it with the carbs on. I've had lower results without carbs before, not that low and no idea why. Was it the same tester? If Harbor Freight tester -throw in trash Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted February 17, 2017 Report Share Posted February 17, 2017 And 2 strokes are supposed to smoke, and usually spooge out the pipe too. You didn't mention oil brand and mix ratio. Quote Link to comment Share on other sites More sharing options...
blowit Posted February 17, 2017 Report Share Posted February 17, 2017 BAD CRANK SEALS WILL GIVE YOU POOR COMPRESSION!! Sent from my iPhone using Tapatalk This is just not correct but no disrespect for trying to help. Quote Link to comment Share on other sites More sharing options...
blowit Posted February 17, 2017 Report Share Posted February 17, 2017 OP, a couple things. I would first verify your comp tester works right. I might recommend you read a post we still have on our site about compression testing. I suspect you might have a setup issue there. If that is accurate, you have a real concern. What you describe certainly sounds carb related but from what I read, it might be wise to network with a local expert and learn a few things here as you might burn a few engines trying to figure some things out. It sounds like you could have some plugged jets, and a carb sync issue. Probably need to start at the top and work your way down. Mull Engineering Quote Link to comment Share on other sites More sharing options...
hoppedupandcutdown Posted February 17, 2017 Report Share Posted February 17, 2017 Leak down test? Sent from my SM-S820L using Tapatalk This, because air leak is probably the cause of your bog and first melted piston. 1 Quote Link to comment Share on other sites More sharing options...
kingster1 Posted February 17, 2017 Author Report Share Posted February 17, 2017 harbor freight tester it is lucas oil 32:1 ratio Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted February 17, 2017 Report Share Posted February 17, 2017 Try a craftsman. Not to bad price wise, and a hell of alot more dependable then harbor freight. Sent from my SM-S820L using Tapatalk Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted February 17, 2017 Report Share Posted February 17, 2017 This is just not correct but no disrespect for trying to help.Lol, maybe he just browsed through to much info in a day. Sent from my SM-S820L using Tapatalk Quote Link to comment Share on other sites More sharing options...
kingster1 Posted February 17, 2017 Author Report Share Posted February 17, 2017 its ironic because this is my first time using this tester on this bike. I just recently brought this harbor freight tester. I will try my old one tomorrow. carb syncing could also be an issue, the hole in the piston is that from overheating or detonation? Quote Link to comment Share on other sites More sharing options...
blowit Posted February 17, 2017 Report Share Posted February 17, 2017 harbor freight tester it is lucas oil 32:1 ratio I highly recommend our post. It could be improved but gets the point across. the gauge itself likely is not the issue, it is the end of the hose that will lie to you. If you have Lucas full synth, that might be a little 'slobbery' of a ratio. Might report back with more intel on that. Here is a few quick tips. When you say 'overheat' I read that to mean total engine overheat, which certain can cause the hole. However, I think you are suffering a more acute condition. detonation is rapid rise in compression after spark and usually on the exhaust side of the piston. IE, erosion on the exhaust side of the crown. A central hole technically 'is' detonation but actually caused by pre ignition. Pre ignition will be caused by extremely high compression, carbon build up, damaged spots holding carbon, super lean jetting, hot plug, etc. Basically with pre ign, something is acting like a glow plug. However, pre ignition means "ignition before we ask it to", it does NOT mean violent combustion. Ignitions just means "lighting the fire", the word detonation has more to do with burn speed. There comes a burn rate that I cannot remember that it is no longer 'burning' at a certain rate, it just rips ass and explodes. What I am getting at is the detonation caused by the high heat and pressure of preignition is what causes the hole. So........ Very likely a lean condition caused the hole..... Or something else... Quote Link to comment Share on other sites More sharing options...
blowit Posted February 17, 2017 Report Share Posted February 17, 2017 Lol, maybe he just browsed through to much info in a day. Sent from my SM-S820L using Tapatalk i hate to ding the new guy, as I am not into hazing but i have seen this before and the next thing you know, the OP is out there ripping his engine and installing crank seals. Though it is possible, a compression test would never show that. This is sounding more carb related but stay tuned. Who know where we are going. 1 Quote Link to comment Share on other sites More sharing options...
kingster1 Posted February 17, 2017 Author Report Share Posted February 17, 2017 (edited) I will most definetly try to get my hands on a leak down tester. I also see where they make a carb sync tool. I need that also. I hope its the hose that's lieing to me. It has to be the hose. It does make sense that an air leak is causing all this mayhem. Edited February 17, 2017 by kingster1 Quote Link to comment Share on other sites More sharing options...
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