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Discussion Starter · #1 ·
Hey All, I've been helping a buddy get a '71 CL350 back on the road after sitting for years. The engine has been rebuilt with new oversized pistons, new valves, and new gaskets all around. It's in the frame now and I'm trying to get the electrical worked out but I can't seem to figure out what mechanical advance I'm supposed to use on the bike. It's a '71 CL350 like I said but I've tried 2 different advance units that the parts fiche and manual say should fit it. Part number 30220-286-014. I'm guessing now that the camshaft in the bike is from a SL350, CB360, or something like that. Does anyone know how I can figure out what advance unit will fit on this camshaft? He lost the original one or never had it, which makes me think that it was discarded because it didn't fit the possibly new cam.

I see some mechanical advance units with 312 stamped on them instead of 286. Does anyone know if the 312 units have a larger cylinder hole for the camshaft?

Also, what's up with the springs on these things? Are they all worn out or do they hold up?

Thanks in advance,
 

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CB, CL, SL cams all use the same advance mechanism. The early fat cams and later skinny cams all use the same advance mechanism.

The advance mechanism part number you posted is the correct part.

CB360 cam won't fit into a CB350.

What isn't fitting? can you post up a picture or two.
 

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Discussion Starter · #4 ·
So even though Honda has a different part number for the '71 SL350's timing advance (30220-312-004) it is the same as the CB and CL's?

I don't have the advance units anymore. I returned them since they didn't fit.

My camshaft end where the advance unit is supposed to slide on measures 11.2mm if that helps anyone figure this out.

I'll get some pictures when I get home from work this evening.
 

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So even though Honda has a different part number for the '71 SL350's timing advance (30220-312-004) it is the same as the CB and CL's?

I don't have the advance units anymore. I returned them since they didn't fit.

My camshaft end where the advance unit is supposed to slide on measures 11.2mm if that helps anyone figure this out.

I'll get some pictures when I get home from work this evening.
The part you quoted for the SL should fit, it just has( slightly) different advance characteristics vs the cb/cl.
 

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Discussion Starter · #6 ·
Ok, so here are some photos if that helps anyone. The first is of my camshaft end. Not sure if that's helpful. Second picture is of the back of an advance unit that looks like the ones I tried. The next two pics are of advance units that are listed as the 286 or 312 kind but have a slightly different back. The cutouts are a different shape and there are two extra holes punched in them. Maybe they have a different sized opening for the camshaft? The last photos is of the front of a 286 type part. Not sure if that's helpful at all.

So are we sure that the 286 and 312 type advances have the same sized cylinder opening for the camshaft? If so, what other camshafts will fit in a '71 CL350?





 

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No other cams fit a the 350's of this vintage other than the two variations, known as fat and skinny. Both have the same dimensions in regard to the advance unit. There are some racing cams available but I've never seen one of those with a variation of this part of the cam.

I currently don't have access to my parts stash to give you measurements .... have to support the economy in a warmer country ..... but all looks correct from your photos.

I have never had any issues fitting an advance unit in place, I have seen a bent shaft where the cam was dropped and I have seen one with an end that had been peened from hammer blows. Yours does not look like it has suffered either of those fates.

I see the screws that hold the points plate in place are there but I don't think they would interfere with putting the two parts together.
 

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So what's the issue here? Your adv unit won't fit on the camshaft, or it won't engage with the pin?
The photo of the camshaft doesn't show the pin.
The second photo down looks like someone tried to secure the adv unit without locking it into the camshaft pin.
Pls confirm the outer camshaft dia and inner dia of your adv units.
 

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Should add to the above photo .... this is a fat cam with the pin in the shaft, your cam may have the pin in the vertical face. Either pin placement works with all the advance mechanisms.
 

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Tom....I moved it....

Tanerrx... To my old eyes, the end of your camshaft looks very slightly "mushroomed" in the pic...and the advance shown has burrs raised by a mispositioned set-pin...
However, measuring the snout of several shafts averaged .4339" which is the 11.02mm you got.......
Even the smallest amount of displaced metal (mushroom or burrs) would hamper the install as tolerances are very close....

Were I you, I would consider slightly chamfering the perimeter at the end of the "snout" with a file.......Feel free to phone to discuss...540-525-5199
 

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Simon, Nice to know I'm not the only one seeing that from the pic....
Possibly a slight burr at about 3 O'clock as well...
I suggested he dress it gently (slight chamfer) with a file....
 

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Discussion Starter · #15 ·
The issue is that the advance unit won't fit on the end of the camshaft. The pin is there but because of the angle of my photo it is hidden. All the other photos are not mine. I pulled them off the internet because I don't have an advance unit on hand. I returned the two I tried from eBay. So I don't have the internal measurements for them. All I know is that my camshaft end is 11.2mm in diameter.
 

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Discussion Starter · #16 ·
Didn't see all the replies before I posted that last comment. I'll get another advance unit since it seems there is no way that it could be a different style camshaft and try to take a file to the end of the camshaft. Thanks for all the help y'all. I'll try to update the outcome when I can.
 

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If it really is mushroomed then I would also check if the end is still straight and not wobbling. Could result in some very interesting ignition timing phenomena.
 
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