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Post by o0ohakko0o on Sept 18, 2015 20:55:35 GMT -6
Yes Jr I found that video and in the process cheers thanks
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Post by o0ohakko0o on Sept 19, 2015 1:38:35 GMT -6
here are the valves though bit hard to see but they are black full of carbon also am i meant to take them off to give a good clean out inside the casing or just the valve stems ( not sure how to get the stems out though ) on the picture below picture 1 , One seems to be smaller than the other   Also with the head off should I look at piston and rings etc ? |
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Post by JR on Sept 19, 2015 7:59:06 GMT -6
Yes I would look at the piston and rings, as you said this engine is dirty! You could have a stuck ring as well. When we get this thing running a good thing to do will be run it for a few hours with a good 10W/40W high detergent oil, drain it and then refill. May want to do this several times after say 20 hours until the engine cleans itself up.
Let's see if we can find some material on how to pull the valves out and the larger valve will be the exhaust valve which is common.
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Post by JR on Sept 19, 2015 8:20:26 GMT -6
Here is a 125cc pit bike engine which is very similar to the 110cc and down toward the end of the video it shows how to remove the valves. He made a home made tool to remove the valves which is easy to do, you have to watch this video on You Tube. Now here is another guy who made a tool to remove the valves. Also one can get the springs and keepers back together without having to buy tools: thescooterprofessor.proboards.com/thread/2431/engine-exhaust-install-springs-compressionWe want to pull the valves out since you have it apart and do what is call lapping them with valve paste/compound which you can get at a auto parts store. Lapping them will insure a good air tight seal. When removing the valves make sure they come out easily and the stems aren't binding. Here is some ways to lap them again without expensive tools: thescooterprofessor.proboards.com/thread/1504/gy-valve-lapping-spring-replacementYou can buy a simple hand stopper valve lapping tool at the auto parts store or any where they sell small engine tools. One that looks like this:  |
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Post by o0ohakko0o on Sept 19, 2015 18:27:17 GMT -6
Jr how can i tell if the rings are stuck or anything im unsure what im looking for etc ? Also with the valve stems after getting those 2 braces out should the stems just easily fall out mine are not just falling out about half way there getting stuck then I have to pull them really hard to get the stems completely out there also was a valve stem oil seal broken only half there and have a look at this piston looks like i need a new 1 of them also as you can see in the photo its been rubbing on something  |
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Post by JR on Sept 19, 2015 21:57:03 GMT -6
If the valves are extremely hard to pull out after removing the springs then there is so much crud in the guides that they are sticking. The piston along with the rings are toast, here is why the scooter won't start, sticky valves and a bad piston. I'm betting the cylinder wall of the head is ruined too. I'd say it's time for a complete top end rebuild. You can clean the valve head up, put new seals in it, lap the valves and clean up the valve stem guides or just buy a complete new head assembly.
Need to look everything else over and make sure this is all you need? You also now know why the engine just quit.
JR
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Post by o0ohakko0o on Sept 19, 2015 23:09:48 GMT -6
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Post by JR on Sept 20, 2015 13:16:07 GMT -6
The cylinder doesn't look that bad, it's possible you could hone it out cleanly? Here is a video demonstrating how to hone a head. You need to remember that if you take too much out the piston will be sloppy and the rings may not do well for long.
If you can clean it up and also can rebuild the valve head assembly it will save you some bucks for sure. You can get the valve guides cleaned up by applying a very small amount of valve lapping compound and plenty of oil on them and then spinning them in the head itself. This will polish both the valve stem and the valve guide so that when you clean them up perfectly and oil the valve stems they will freely move up and down again, then lap the valve into the seat, install new seals and put it back together.
If you can get the piston cylinder to clean up then all you'll need is a new piston, rings set and gaskets. If the wear mark in the head doesn't clean up quickly then you'll need a new cylinder head too.
But with a top end rebuild it should run like new again.
JR
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Post by o0ohakko0o on Sept 20, 2015 23:11:14 GMT -6
Hi there JR I'm going to try and recover the cylinder head also clean the valve stems etc and also try to clean the piston cylinder but obviously buy new oil seals and new piston and rings with the piston cylinder can I try to clean that up with some of that lapping compound ? Oh and my new gaskets arrived today
Also unsure what size piston to get
Also I have to buy a pair of valve stems as one of them is bent
I just measured the old piston and it measured 52mm in diameter
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Post by JR on Sept 21, 2015 17:56:54 GMT -6
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Post by o0ohakko0o on Sept 21, 2015 23:50:14 GMT -6
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Post by JR on Sept 22, 2015 11:32:25 GMT -6
Most engines I know indeed they are always the same length but it's very common for the head of the exhaust valves to be larger. Very strange you had a bent valve? I'm thinking it hit the piston? Was all the little half moon keeper clips on the valves when you removed the springs?
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Post by o0ohakko0o on Sept 22, 2015 15:46:12 GMT -6
Yes they sure we're , I ain't looking forward to putting them back on when I have to they were hard to get off without the correct tool
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Post by JR on Sept 23, 2015 5:41:08 GMT -6
BTW when the new valves come in you will still have to get some lapping compound (fine) and seat the new valves to the head for a perfect seal. Do not dare put it back together without lapping the valves.
JR
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Post by o0ohakko0o on Sept 23, 2015 13:45:34 GMT -6
Ive got the lapping compound JR bought it the other day
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