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Think I found the problem

motogtp

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I have been struggling with running rich and fouled plugs ever since I got it running. 1978 SS with 6100 miles that runs well with new plugs. I finally ran a compression test today. Dry test #1-80 psi, #2-75 psi, #3-70 psi, and #4-70 psi. Wet test #1-85, #2-88, #3-82, and #4-90 psi. I know these numbers are low but what exactly are they telling me? Bad rings, valves, or both? Either way it looks like I am opening up the top end.
 

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Yup. Both the throttle and choke were wide open. I think I read somewhere that 100 psi is considered a minimum.
 
170 is Honda spec. I say anything below 120 is bad unless there is a huge cam in it. Looking at the compression numbers I would say you have some stuck rings and a couple of valves that have issues. You should increase about 10 psi at least with oil. I guess you will find out when it comes apart. I am suspect about the 6000miles on the bike...something doesn't add up. Take pictures when she is apart!
 
170 is Honda spec. I say anything below 120 is bad unless there is a huge cam in it. Looking at the compression numbers I would say you have some stuck rings and a couple of valves that have issues. You should increase about 10 psi at least with oil. I guess you will find out when it comes apart. I am suspect about the 6000miles on the bike...something doesn't add up. Take pictures when she is apart!

I am skeptical, too. I hope the cylinders are in decent shape. I will take pictures as I tear her down. Haven't been inside an engine for awhile so hopefully I can shake off the rust. Going to look at a Yamaha 1100 Special tonight so I have something to ride in the meantime. Thanks for all your great input DD.
 
Moto i had a '80' 1100 special very fast bike, put 81,000 miles on it before i sold it. If it has the origanal exhaust make sure the cross over is'nt rusted out cant get them any more and wont run proper with out it.
 
Moto i had a '80' 1100 special very fast bike, put 81,000 miles on it before i sold it. If it has the origanal exhaust make sure the cross over is'nt rusted out cant get them any more and wont run proper with out it.

Good advice I will check it out. This is a 1980 as well. Another barn find with a gawdaweful Aero Pacifica front fairing and a torn up seat cover. But only 26,000 miles, in decent shape, brakes are free, and it ran last year. Retired farmer says he will have it running when I get there and wants $400 to get it out of his shed. If I buy it I think I am going to go for more of an urban moto look.
 
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