"Patina" The 1973 CB175 Cafe Racer

Texasstar said:
Did you leave your carbs on? Check to see if you have fuel in your oil...we had this same problem with Lucky if your oil smells like gas it will run like a two smoke..


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Gassy oil will also turn the cam and journals into cottage cheese in short order
 
Re: "Patina" The 1973 CB175 Cafe Racer

1sttimer said:
Please noooooo. How can I tell that seals are bad?
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Continuous smoking from the exhaust. Those things are cheap and you change them every time the motor is apart for service (every 30 years on a moped like this)
 
Re: "Patina" The 1973 CB175 Cafe Racer

Always remember the glorious thing about working on these twins...they are female. They will let you know ever time you have done something wrong ;) ;)


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I'm gonna buy a compression tester and see where that gets me. From a video I saw with Brian Fuller, a compression that increases with a drop of oil in the cylinder means it's the rings. A compression that stays the same with a drop of oil means it's the valves. Logically this makes sense and I have yet to check compression after the new rings. I'm interested to see what it is anyway. Sorry for the late response - not getting notifications on my phone anymore for some reason.
 
The only solace I can take in this bike right now is that the bottom end is great now (because I fixed that idiot's mistakes) and the bike is charging because of the new stator. So there's that...
 
Even with perfectly sealing valves, the seals can still leak oil when they open.

175 seals are pretty basic and wear out fast. Fortunately they are easy to change. You could upgrade to all CB200 valve guides with modern seals for not a lot of money.
 
Re: "Patina" The 1973 CB175 Cafe Racer

Interesting compression results. Dead cold 120 left, 105 right. Added a little oil. 134 left, 205?????? Right. That didn't seem right so I let it settle and got 155 right.
 
Re: "Patina" The 1973 CB175 Cafe Racer

Got it warm this time. 117 on the right, 123 on the left.
 
Re: "Patina" The 1973 CB175 Cafe Racer

Throttle wide open, kicked until it stopped rising. The right side jumped from zero to 30 first kick. The left side 0 to 60 first kick.
 
Re: "Patina" The 1973 CB175 Cafe Racer

Throttle wide open?


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Re: "Patina" The 1973 CB175 Cafe Racer

Valve lash was set to .006 a few months ago. They haven't been checked since, so I'll do that.
 
Re: "Patina" The 1973 CB175 Cafe Racer

Cb200 tappet is .002" per the manual set when it is cold...I will check the cb175 manual give me a minute


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Re: "Patina" The 1973 CB175 Cafe Racer

8054096caab15de9b7402c0e69009b4f.jpg
.002"


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Re: "Patina" The 1973 CB175 Cafe Racer


Texasstar said:
8054096caab15de9b7402c0e69009b4f.jpg
.002"


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Yeah I found that too. 3x is not good. Why exactly does valve clearance matter exactly? If it was too loose, they would open slightly later, but how does that impact compression numbers? Sorry for my ignorance :)
 
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