Author Topic: Honda CL175 Carb. Questions  (Read 3788 times)

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Offline iya0yas

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Honda CL175 Carb. Questions
« on: June 18, 2012, 07:15:25 PM »
Back again....this time with a few carb questions.

1972 CL175 K6 w/5,172 miles...

Finally got my head (cyl. head ;) issues sorted out with a valve job, fixed the leaking spark plug, honed cyl's., new pistone, rings, gaskets and set all valve clearances to 0.002".  I also reset the timing with a timing light so it's spot on now and I finally got the engine running...hooray!

Per the Clymer manual I set the idle mixture and speed screws accordingly.  With the engine warm I shut it off the disconnected the left spark plug and proceeded to tune the running carb so that it would idle properly.  Leaving the idle mixture screw at 1-1/4 turns out I tried to adjust the idle speed screw but could not get the idle below 2500 rpm without the engine stalling.   Okay, so I switched carbs. and tried to repeat the process for the right carb. but basically got the same result.  I verified I'm getting fuel to both carbs, good spark with new NGK plugs (OEM spec) and no airflow restrictions.

I've since removed the carbs for inspection and this time paid closer attention to the pilot and main jet #'s.  Both main and pilot jets were the same for both carbs at 92 & 35, respectively.  The Clymer manual specifies 90 and 38.  Could the smaller pilot jet be causing the lean running condition at idle consistent with the symptoms described above? 

I also double checked that idle and main circuits within the carb body are clear of any obstructions.

I purchased this bike from the original owner (a woman) and she told me before I bought the bike that no modifications of any sort were done to the bike.  Perhaps her dealer could have swapped jets?  Perhaps the Clymer manual is incorrect?

Any thoughts on this topic would be appreciated...thanks-
« Last Edit: June 18, 2012, 07:18:44 PM by iya0yas »

Offline Old Scrambler

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Re: Honda CL175 Carb. Questions
« Reply #1 on: June 19, 2012, 08:40:52 AM »
Lots of individual jet changes occurred during that period of time....Clymer is a generalist......not the HONDA manual.

The extra load of trying to set idle with one cylinder not firing is new to me. How does it idle with both plugs connected?

Is the airbox and filter clean?  Any air-leaks on the manifold?  Try a little more air on the screw and run premium grade fuel. 
Dennis in Wisconsin
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