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Discussion Starter · #1 ·
Rode the CB200 in to work this morning for the first time. Lots of fun! except...
I have not been able to get the bike to idle whatsoever. Even though the throttle stop screws are almost all the way in.
The points and timing have been set. The air filters are newly refurbished with polyurethane foam and fairly well sealed.
I tried to sync the carbs, but the signals would barely register on my gages. I think I may have had leaky connections at the manifolds. The exhaust is not at all stock. It's a 2-1 with huge primaries (I'm guessing 1.25" O.D.). Under full throttle it runs pretty well. Part throttle sputters and pops - but never dies. If you let it drop below 1.5k rpm it just stops running. The carbs have been cleaned and rebuilt with the keester kits. Two new floats. New condenser. Ignition coil wires replaced. New plug caps. New plugs. Since I couldn't get the syncronizers to work, I bench synced as best I could. I used a 7/64" drill bit.

Is this throttle stop opening too large? Could the jetting be screwy? Is it the aftermarket exhaust messing me up? Any ideas what to try next would be greatly appreciated.

Kenolds
 

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What are your compression readings?..........
 

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Discussion Starter · #3 ·
I did a compression test to the best of my abilities several months ago. I don't remember what I got exactly. but I was convinced it was not "the problem". If I had to spit out a number. I would say 95psi on both cylinders. My test method was s little crude. I don't have the proper threaded adapter for my compression gage, so i tried to modify a spark plug -didn't work. I ended up cutting the threads on the lathe into a piece of UHMW. I am no machinist - they turned out pretty rough - but worked well enough to convince me that the compression was OK.

Thanks,
Kenolds
 

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Compression specs for a CB 200 are 170PSI... Below 153 it needs re-ringed...(at the minimum, possibly rebuilt....)
A "bad" reading engine won't idle......but still may run (somewhat).....
......Your move............
 

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Discussion Starter · #5 ·
Well, I'm not sure wherer I got 95 from??? - but I just redid my crude compression test and got 130psi. My tester has a very long hose, but also has a schreader valve down by the cylinder. The UHMW adapter I made does add a little volume to the system, but not much more than a stock adapter. Do you think 130psi is low enough to prevent smooth idling?
By the way - thanks so much for your help. I really enjoy tinkering on this old bike. I thinkI'll really enjoy riding it someday, too.

-Kenolds
 

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Again, ...153PSI ABSOLUTE MINIMUM!..........
 

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Discussion Starter · #7 ·
Can you please describe the compression tester that you use to get the numbers that you quote. I am curious how much volume your tester adds to the compression chamber (thereby reducing the compression readings). I don't want to open up this motor if I don't absolutely need to.

Thanks again for your input.

Kenolds
 

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kenolds said:
Can you please describe the compression tester that you use to get the numbers that you quote. I am curious how much volume your tester adds to the compression chamber (thereby reducing the compression readings). I don't want to open up this motor if I don't absolutely need to.

Thanks again for your input.

Kenolds
He's not quoting #'s he got from another tester, he's quoting from the manual. I believe it would be in your best interest and for your peace of mind to get your hands on a legit compression tester rather than a "crud" one. It honestly doesn't take much to get a bad reading which will lead you on a wild goose chase. You can buy an adequate one for $30-40 or you can rent one for $5.00/hr at most rental places.

Just my 2 cents...
 

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Discussion Starter · #9 ·
My tester is the $30-40 kind. The "crude" portion is the adapter for the spark plug hole. I am pretty confident that most any quality tester will give similar results. However, I have heard from the SOHC4 forum that the compression numbers Honda gives are only valid for their rather specialized exactly perfect custom made compression tester - so that's why I wanted to know what kind of tester was being referenced.

SO - now that it looks like rings are in order - Anyone know where I can buy rings (or if I'm in there, I'd probably just rather buy .25 over pistons and rings)? They are not available through "regular" Honda dealerships. I have already put in an email to WesternHonda and see that there are some pistons on E-bay.

Thanks
Kenolds
 

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So...130 PSI.... That was with engine hot, no plugs, no choke, throttles wide open right?......... The reason for this question is IF it was done cold, (or otherwise improperly), you might be able to just lightly hone and replace the rings and gaskets.....
Regardless, the conditions when it's torn down will tell.........
 

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Discussion Starter · #11 ·
130 psi was obtained under these circumstances:

Engine warm to the touch - not hot.
One plug installed, compression tester in other plug hole.
Choke off.
Wide Open Throttle.
Kick Starter Only - Electric start does not work.

I'll get it warm tonight, remove the other plug, and see if I can hot-wire the starter and report.

- OK make that soem night soon - it rained last night.

Thanks Again
Kenolds
 
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