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Old Feb 21, 2016, 06:00 PM
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Help!
Sudden loss of compression?

I have recently purchased a xtm buggy with a RB WS7 engine on it used, it had pretty good compression on it but today I took it out for its first run and when I got it back to the house it has barely any compression at all. any help will be appreciated, thanks in advance
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Old Feb 22, 2016, 09:19 AM
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Appears piston/sleeve could be worn out. Cause can be from not using a fuel filter, not the correct oil lube fuel or the engine was leaned out from the previous person. You should buy a new piston sleeve and break in engine. If you can start the engine again it may last a little while. Buying a used nitro can be a real pain!
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Old Feb 22, 2016, 03:16 PM
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Originally Posted by txt killer View Post
Appears piston/sleeve could be worn out. Cause can be from not using a fuel filter, not the correct oil lube fuel or the engine was leaned out from the previous person. You should buy a new piston sleeve and break in engine. If you can start the engine again it may last a little while. Buying a used nitro can be a real pain!
Thanks, i started it today is seems to run ok, I'll see if I can find a rebuild kit for it and see if that helps
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Old Feb 22, 2016, 03:23 PM
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here..http://www.dynamiterc.com/Products/D...ProdID=DYN2514
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Old Feb 22, 2016, 03:30 PM
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Originally Posted by Nitrboy01 View Post
Thanks, i started it today is seems to run ok, I'll see if I can find a rebuild kit for it and see if that helps
The only real way to tell if you need a new piston/sleeve is to use a compression gauge or disassemble the engine and see if the piston pushes all the way threw the sleeve when the parts are removed from the engine.
The only choices are to buy a new piston sleeve http://ashfordhobby.com/detail.aspx?ID=2016 or have the piston/sleeve re pinched. Just by the cost of replacement parts it's expensive to replace.
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Old Feb 22, 2016, 04:53 PM
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Originally Posted by txt killer View Post
The only real way to tell if you need a new piston/sleeve is to use a compression gauge or disassemble the engine and see if the piston pushes all the way threw the sleeve when the parts are removed from the engine.
The only choices are to buy a new piston sleeve http://ashfordhobby.com/detail.aspx?ID=2016 or have the piston/sleeve re pinched. Just by the cost of replacement parts it's expensive to replace.
Thanks for the help
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Old Feb 22, 2016, 05:23 PM
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Originally Posted by txt killer View Post
The only real way to tell if you need a new piston/sleeve is to use a compression gauge or disassemble the engine and see if the piston pushes all the way threw the sleeve when the parts are removed from the engine.
The only choices are to buy a new piston sleeve http://ashfordhobby.com/detail.aspx?ID=2016 or have the piston/sleeve re pinched. Just by the cost of replacement parts it's expensive to replace.
thanks for the help
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Old Mar 02, 2016, 12:44 PM
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Quote:
Originally Posted by Nitrboy01 View Post
I have recently purchased a xtm buggy with a RB WS7 engine on it used, it had pretty good compression on it but today I took it out for its first run and when I got it back to the house it has barely any compression at all. any help will be appreciated, thanks in advance
If you're in a cold climate, yes your engine will have more compression cold than hot. Take a hair drier and heat it up and see if it happens on the bench.
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Old Mar 04, 2016, 02:41 AM
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Got a question guys. My brother has losi 8 2.0 with the 350 nitro motor. It's about 4 years old and has lost its tune. We have leaned it out as good as we can but it has no low end power. Do u think it may be the compression. He's gonna just buy a new 350 for it but is wondering what's up with this one.
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Old Mar 04, 2016, 07:06 AM
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It could be that? If you want you engine to last longer don't rush on maxing it out on the high fast. Also use fuel with more oil lube. These new engines today are more expensive to rebuild today. So try and take it easy on them to last longer.
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Old Mar 04, 2016, 07:15 AM
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Yea my buddy sold it to him and he used to race it but it sat for a while. So we got it started and it just didn't run right so we took carb apart cleaned and restored back to factory setting and still no low end power. Guessing this baby is close to kicking the ol bucket.
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Old Mar 04, 2016, 07:50 AM
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The only way to tell is to use a compression gauge to see how low the compression is? It could be as simple as putting new o-rings in the carb? Due to the age and sitting I would see how much it costs to replace the o-rings in the carb and a new piston sleeve. Re-pinching is another option. New engines are expensive. I'm blown away at how much nitro engines are today! they are twice the price of when I was able to buy new. Now all I do is look for used engines and new parts as it is way cheaper to keep running old engines. When I run out of engines and can't find parts anymore I done with nitro. Gas is way cheaper to run now.
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