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Correlation between CB350K engine numbers and 10,500 rpm redline tachometers?

ausman1000

ausman1000

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Here is a pic of my tach. The engine number begins with 109 and the frame number begins with 104 making it a CB350K1 model I believe. In the past I was of the belief that 10,500 redline tachs were associated with fat cams. My engine number according to Partszilla would contain the thin cam p/n 14101-286-050. Starting to think maybe the gauge cluster I have is not original to the bike. hmmm

sorry, don't know why the pic went sideways

5.jpg
 
Your 350 is in fact a K1. Far from an expert on the 350 myself so I can't comment on when exactly the redline was changed but this page from the Honda ID Guide confirms your bike. Check the link in your Welcome Package (or in the link to it at the top of the forum in many locations) for a link to explain picture orientation.

Kyc3lfE.jpg
 
I don't recall redline #s and can check later today, but you can also tell early and later model gauges by their construction. The glass in earlier protrude above the aluminum housing, and are recessed in later ones. I can't tell from your photo if they're the same or different.
 
MrPepper said:
I don't recall redline #s and can check later today, but you can also tell early and later model gauges by their construction. The glass in earlier protrude above the aluminum housing, and are recessed in later ones. I can't tell from your photo if they're the same or different.
Click to expand...

Both gauges have glass that do protrude above the housing.
 
My 1970 K2 has that same tach with a 10,500 RL. Engine number starts with 2. Never been inside the motor but a CL motor with engine number also starting with 2 I recently tore down had a fat cam in it.


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RockReef said:
My 1970 K2 has that same tach with a 10,500 RL. Engine number starts with 2. Never been inside the motor but a CL motor with engine number also starting with 2 I recently tore down had a fat cam in it.


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Click to expand...

Ok, your info is something to ponder. Maybe my 10,500 tach is period correct for a K1 but minus the fat cam.
 
I can state for fact that the 050 cam is a skinny cam with a perpendicular drive pin.
I have a 108**** engine that had a fat cam, engine number makes it a K1.
 
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LongDistanceRider said:
I can state for fact that the 050 cam is a skinny cam with a horizontal(parallel to cam) drive pin.
I have a 108**** engine that had a fat cam, engine number makes it a K1.
Click to expand...

Would it have been unheard of for honda to use up old parts and that's why we see the fat cam in new engines?

It would seem unlikely that a PO had the cam replaced. Though I suppose it's possible.

It would seem more likely the reference materials are wrong.
 
My 68 CL350 with engine 1012--- and frame 1016--- has the fat cam and the 10,500 tach. The gauges look Like this
100_4215.jpg not the raised lens's on the gauges 100_4216.jpg
 
When you have a chance, can you see if your fat cam has a vertical drive pin (with flat and not rounded ends) and the tip where the spark adv slides is more beveled than the skinny cam?

Those are the differences I noticed on mine, but I haven't been able to locate the other to check against


LongDistanceRider said:
I can state for fact that the 050 cam is a skinny cam with a horizontal(parallel to cam) drive pin.
I have a 108**** engine that had a fat cam, engine number makes it a K1.
Click to expand...
 
1968-1970 CB and CL 350s have 10,500 rpm redline tachs. The 1971-1973 models have 9200 rpm redline tachs. I don’t think the fat cams were used past 1969 or maybe early 1970. A look through the parts books for cam part numbers might shed more light on things, but my guess is there were both a fat cam and then a skinny cam with roughly the same cam lobe profile, and then a switch to a slightly milder cam the second half of 350 production.
 
all CB350 cams (or all the ones I've measured and WebCam have measured) are basically the same,that being both INT and EXH lobes .265" to .270" lift and 230 degrees duration @ .040" lift. Which is pretty mild...and that goes for both early and late cams. Almost no difference between any of them..

cam mapping fixture.jpg
 
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MrPepper said:
When you have a chance, can you see if your fat cam has a vertical drive pin (with flat and not rounded ends) and the tip where the spark adv slides is more beveled than the skinny cam?

Those are the differences I noticed on mine, but I haven't been able to locate the other to check against
Click to expand...
Both of my new cams are still in Sturgis, a**hole hasn't shipped them back yet. I was in error about the drive pin, the 050 cam has a perpendicular drive pin and the 070 has the horizontal. Cams don't have pins in them new.
 
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