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Post by duosport on May 9, 2010 14:08:44 GMT -5
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Post by 2strokd on May 9, 2010 14:33:36 GMT -5
Trust me here...Making yourself one of these might(will) save you money in the long run! 49ccscoot.proboards.com/index.cgi?board=yamajog&action=display&thread=425I think your plug situation is common, if it seals, and a leaktester will tell you if it does, then its not the(A) problem. No offense but i think your turning a little aint mound into a mountain the way your going with this. |
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Post by 90GTVert on May 9, 2010 14:41:08 GMT -5
Those inserts should work if you do need them. You could do a quick mock-up and I would think you should be able to feel it if pressure was escaping when you turn the engine over. Use a little soapy water and you'll see it if pressure is escaping there. The leakdown tester will also work for that purpose and find other leaks if they are present.
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Post by duosport on May 9, 2010 14:45:32 GMT -5
Trust me here...Making yourself one of these might(will) save you money in the long run! 49ccscoot.proboards.com/index.cgi?board=yamajog&action=display&thread=425I think your plug situation is common, if it seals, and a leaktester will tell you if it does, then its not the(A) problem. No offense but i think your turning a little aint mound into a mountain the way your going with this. How so? Your tester will tell me I have a leak somewhere. I already know I have a leak right? So what will I learn from it? It will not pin point that it is the spark plug now will it? I already know I have a leak of compression in the top end. I have been extremly logical in it all. Lots of people here have been illogical. Wanting me to check Variators and reeds. Really! The problem I am having is in the top end only. I do not need at this point to register leaks in the whole engine including crankcase. So if I had the pressure tester right now and came back online and said: "yes it is losing pressure." What would you then say to me? |
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Post by duosport on May 9, 2010 14:48:24 GMT -5
Those inserts should work if you do need them. You could do a quick mock-up and I would think you should be able to feel it if pressure was escaping when you turn the engine over. Use a little soapy water and you'll see it if pressure is escaping there. The leakdown tester will also work for that purpose and find other leaks if they are present. with 92 PSI clearly I already know I have a leak right? The question is where in the top end is it? Are you saying I should run the engine and spary soapy water on the spark plug area? |
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Post by 90GTVert on May 9, 2010 14:56:32 GMT -5
I meant just crank it over to create pressure in the cylinder. Actually, the leakdown tester WILL pinpoint leaks. You pump it up and it puts pressure inside the engine. You can usually hear a leak and trace it. You can put a little soapy water solution over the area you suspect is leaking if you aren't sure and the pressure escaping will cause bubbles. It can help you find leaks in the intake, reeds, case, spark plug hole, exhaust if you set it up that way, head gasket, and base gasket. I'm not so sure how well it would work for a liquid cooled engine with the head and base gaskets (sorry, I have yet to have the pleasure of working on an LC 2T). Knowing that, do you still believe that when we suggested a leakdown test some time ago it was illogical? I never owned a leakdown tester myself until recently, and now I realize how great of a tool it is if you really want to get your engine running tip top. You can run with small leaks and never realize it until you do a leakdown test sometimes. Fix the leaks and next thing you know the engine is easier to tune and runs better. It's not a miracle worker, but it's a real nice thing to have in your toolbox if you plan on servicing your own 2T.
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Post by duosport on May 9, 2010 14:56:29 GMT -5
Mountains out of mole hills indeed!
I have run the engine and poured soapy water around the base of the plug...lots and lots of pretty air bubbles formed. A nice frothy pile of suds were produced. It is leaking big time from the spark plug hole.
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Post by 90GTVert on May 9, 2010 15:01:26 GMT -5
Glad you found your leak. Give it a compression test once you get those threads repaired just to be sure and if it runs well you'll know what numbers you are looking for if it starts feeling weak in the future.
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Post by duosport on May 9, 2010 15:01:36 GMT -5
I have major air loss through the spark plug hole. All else has been pretty well ruled out. I have brought the head and cylinder top to spec on flatness. When I first removed the rings from the piston a couple of months ago it was pretty clear that the top piston was worn smaller. So now the rings are replaced. I have checked the tolerances as bes I could on the rings piston and bore. So that leaves the spark plug hole wich is obviously losing pressure in a big way.
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Post by duosport on May 9, 2010 15:11:57 GMT -5
...You can put a little soapy water solution over the area you suspect is leaking if you aren't sure and the pressure escaping will cause bubbles. It can help you find leaks in the intake, reeds, case, spark plug hole, exhaust if you set it up that way, head gasket, and base gasket. I'm not so sure how well it would work for a liquid cooled engine with the head and base gaskets (sorry, I have yet to have the pleasure of working on an LC 2T). Knowing that, do you still believe that when we suggested a leakdown test some time ago it was illogical?.. Look I am on limited funds at the moment. I did not buy a caliper gauge let alone put together a 40 dollar pressure tester. I felt the pressure tester was not going to really give me any further info about the top end that I could not find without it. As far as your point about the liquid cooled engine is concerned that is exactly why pin pointing a leak in the top end is difficult. It could leak right into the water jacket and you could not see it. I found my flatness of head and piston to be well out of Malaguti's tolerances. Perhaps I was leaking into the cooling system. I did the soap water test around the spark plug and it is frothing all the way around it. so now what is my next step? |
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Post by 2strokd on May 9, 2010 15:11:50 GMT -5
Juss tryin to help man, sorry if your PO,ed  . Hell in know its a b!tch to find, fix problems with these things and ive been turning wrenches all my life. I was suggesting making a leak down tester because in the long run i was hoping to save you money by not having to throw cash at one part after another until the problem is fixed  ! I really hope its just the plug threads, and you can fix it with a helicoil or something else cheap. Maybe you could wrap your plug threads with electrical tape or pipe thread tape? It would temporarily tell you how much more power you will have by temporarily sealing the plug. Also sometimes the crush(seal) washer gets warn on plugs and wont seal. A new plug might fix it? |
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Post by duosport on May 9, 2010 15:21:50 GMT -5
... I really hope its just the plug threads, and you can fix it with a helicoil or something else cheap. Maybe you could wrap your plug threads with electrical tape or pipe thread tape? It would temporarily tell you how much more power you will have by temporarily sealing the plug. Also sometimes the crush(seal) washer gets warn on plugs and wont seal. A new plug might fix it? Really the plug rocks back and forth before being screwed in all the way. there is entirely way too much play in it. I see no evidence that the previous owner cross threaded it, so perhaps he simply screwed the plug in too tight too often. The scooter has 4,000 miles registered on it. Perhaps the rings were the original set. It is my understanding that rings need to be changed pretty often on a 2 stroke. If this is so that would be a lot of miles on the original set right? Anyway it is a good feeling to have the rings changed on it and the tolerances checked and the head flatness corrected. If I can fix the plug leak and that corrects the PSI problem, then I will count myself ahead. Your'e not POing me off at all. I appreciate the advice. I will be making myself a pressure testor and buying a caliper when the funds start rolling in. Meanwhile I will look for the best means to accomplish my problems on a limited budget. |
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Post by duosport on May 9, 2010 15:32:34 GMT -5
... Maybe you could wrap your plug threads with electrical tape or pipe thread tape? It would temporarily tell you how much more power you will have by temporarily sealing the plug. Also sometimes the crush(seal) washer gets warn on plugs and wont seal. A new plug might fix it? You know what I just did? I put some teflon tape on the spark plug threads and screwed it in. I started it up and took off and I will be damned if that thing did not wind out and go 28 mph straight up the hill! |
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Post by duosport on May 9, 2010 15:35:26 GMT -5
I wonder if there is any kind of heat resistant tape I could put on the threads for a semi perminant solution?
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Post by Fox on May 9, 2010 16:30:25 GMT -5
I wonder if there is any kind of heat resistant tape I could put on the threads for a semi perminant solution? Aluminum foil? Lead foil? I would try one layer of aluminum foil around the plug threads and use a generous amount of WD40 or grease even on it so it goes in nice. Might work as a temp solution. |
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. Hell in know its a b!tch to find, fix problems with these things and ive been turning wrenches all my life. I was suggesting making a leak down tester because in the long run i was hoping to save you money by not having to throw cash at one part after another until the problem is fixed 
!
