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Post by wizardaeon on Sept 25, 2011 23:45:51 GMT -5
Ok im pretty sure my engine just has low compression. I know Ive got good spark and its getting fuel fine.
Im just not sure where to start with this. I dont think I can do a engine rebuild soon and besides the weather is starting to get cold and rainy (its virginia)
I did notice 1) my kickstart doesnt do anything, it just goes down and doesnt spring back like its supposed to. 2) the electric starter works fine as long as I have a good charge on the battery.
When I try to start it it sounds like it wants to start.
I just want to know where to look as to whats causing low compression. I dont have a actual compression gauge to check it I use my finger in the spark plug hole. It pushes my finger out, but in puffs.
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Post by carasdad on Sept 26, 2011 0:27:12 GMT -5
Check your valve lash(valve clearance) if too tight the valve won't seat and you will lose compression and vacuum....  |
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Post by bvance554 on Sept 26, 2011 0:43:53 GMT -5
It is supposed to only push your finger out in 'puffs.' The piston is moving up and down as it cranks. Find a compression gauge.
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Post by meitianman on Sept 26, 2011 1:39:43 GMT -5
as mentioned above valves can cause compression loss, along with bad head gaskets, rings, and worn cylinders. if you turn over the engine slowly by kick starter till it hits its compression stroke then continue turning the engine listen for a hissing sound, it can help lead to where the air is leaking out, if the oil filler plug is out and you can hear the hissing in there quite well then its probably rings, but if you can hear it in the exhaust or carb it could be a mis-adjusted/damaged valve. could put a few drops of oil in the cylinder then kick it over without the spark plug a few times to spread the oil out and then try your thumb check to see if it feels like it has more compression, ive used this many times to check the rings/cylinder on a engine.
how many miles on the engine? have you adjusted your valves as mentioned above? they can calls all kinds of issues when slightly off spec.
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Post by wizardaeon on Sept 26, 2011 10:09:25 GMT -5
Ive adjusted the valves multiple times, according to the specs in my manual
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Post by Pony66 on Sept 26, 2011 10:14:12 GMT -5
Go to Autozone, they will loan you a compression tester for free.
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lbw1
New Puppy Dawg
Posts: 1
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Post by lbw1 on Oct 1, 2011 9:17:18 GMT -5
I am guessing it is a 49cc gy6? If so I usually get 140psi engine compression. If not look closely at the valves. They are usually the culprit.
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Post by qwertydude on Oct 1, 2011 13:41:38 GMT -5
Are you sure it's compression? Sometimes a bad spark plug will fire in the air but not under compression. Make sure you have a good spark plug and it's firing then try to start the engine.
If it still doesn't want to start, try some starting fluid. If it does start you're facing fueling issues, not compression.
Lastly it's really hard to tell how well you're adjusting your valves. A lot of times people say they adjusted their valves but did it wrong, like tightening the nut without checking the lash afterwards, this ends up with you tightening the valve lash. Remember to double check after tightening the nut.
If after those fail then I'd start looking at compression, and as a last resort, pulling the head and cylinder to inspect everything.
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Post by skuttadawg on Oct 4, 2011 12:49:10 GMT -5
I had a piston crack and another totally get fried causing no compression I could push down kickstart with one finger
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Post by wizardaeon on Oct 5, 2011 11:11:07 GMT -5
gonna try the stuff you guys suggested today. dont know about the compression tester, I tried buying one before and coudnt find one. (for spark plug socket)
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