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Discussion Starter · #1 ·
I'm trying to restore this bike but ran into a few issues when I got to the cam shaft and valve springs. I am wondering if anyone else has had the same problem.

So, when inspecting the cam shaft I noticed the manuals I have (Honda 1968, Honda 1974, and Clymer 2006) said that the lobe diameter (largest measurement around the lobes) should be measured at 36.858 to 36.898 mm or 1.451 to 1.453 inches standard and replace if under 36.68 mm or 1.444". When I measure the lobes for the cam shaft that came with my bike they measure above 39 mm. Also most of the replacements I have found (1970, 1971, and 1973) are also around this size. The manuals are for a range of bikes but all of my other parts I inspected fit the spec so I thought it strange that this is the only one that is different.

Also, on the springs I measured the outer valve springs to the same specs given in the manual but the inners were under. I measured about 39 mm on one and about 38.6 or 38.7 mm on the others but the manual I have says replace of under 39.3 mm. I bought some stock ones off of a website called bor-tech and they told me they were slightly used but still usable. When I measure the ones they sold me they are measuring almost exactly the sizes as the inner spring that I originally had. They said I can return them but I find this all a little strange.

I was wondering if the lobes on the cam shaft are larger, maybe the springs compress more so then shorter springs are ok. I don't know. I am new to this but I do know all of this stuff should be very precise so I don't want to use just any old part especially if they don't agree with any of my manuals.

Has anyone else run into this?

Also, if anyone has a camshaft that matches the one for my bike could you tell me what you guys measure for your lobes?
 

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is your bike a k4 or k5?
 

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I have a cl350 k4 in the garage I can measure for you if you like but I don't know if it's the same as K5...might be
 

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Discussion Starter · #5 ·
I am pretty sure they are the same. They had the same part number at least. Yeah let me know the lobe diameter (longest section) when you get a chance.
 

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Discussion Starter · #6 ·
By the way guys this is the last thing I need to figure out and my engine will be complete after cleaning, sandblasting, and painting every piece. I took apart everything and inspected everything and it's so freaking close. Someone must know if 39.00mm inner springs are okay to use! I really appreciate the help.

-Kitty
 

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I just measured my '72 CL350K4 with just under 7K miles. cams show some wear with slight pitting
from left to right on the cam shaft here are the numbers:
1.566
1.561
1.564
1.562
 

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I'm curious about the springs as well. Mine are a little under what the manual says, and I'm wondering if I can put off getting new ones. I really want to finish assembling and ride (and not wait another week for part delivery).

Will
 

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Hey outable, could you post a pic of the pitting/spalling on your camshaft? Mine has some as well, but I don't know how much is okay. Ideally I'd keep my valve springs and camshaft for a few thousand miles and replace them both at the same time later on.

Thanks,
Will
 

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Discussion Starter · #10 ·
I just measured my '72 CL350K4 with just under 7K miles. cams show some wear with slight pitting
from left to right on the cam shaft here are the numbers:
1.566
1.561
1.564
1.562
Thanks for the measurements. :D I guess that means I can keep the cam that I have.

If anyone has any spring measurements that they know are fine to use, let me know. Thanks

-Kitty
 

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Spring "free length" (where critical) is usually specified in the manual.....Shorter than specs is time to replace......Springs are relatively inexpensive.....

I guess this also means you don't want that camshaft as well........ :D Steve
 

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Discussion Starter · #12 ·
Actually, what kind of condition is the camshaft in? Because mine does have pitting or spalling on the lobes I figure I'll have to replace it eventually, just not sure when. A back up is always a nice thing to have. If you have pictures or anything ill take a look.

-Kitty
 

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Discussion Starter · #13 ·
OK. I bit the bullet and just bought new springs for $35, probably should have just bought them in the first place. Coming tomorrow!

I'll post the free length of the new springs just incase anyone is interested. By the way, I have never found a cam shaft that measures 36 / 37 mm or whatever my manual says. I am guessing those are not the measurements for my cam shaft.

Kitty
 

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Discussion Starter · #14 ·
If anyone was interested, the new inner springs measure to be all around 39.60 mm. Glad I just bought new ones.

Kitty
 

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Discussion Starter · #16 ·
I found the springs at Montgomeryville Cycle Center in PA phone # (215) 712-7433. Im sure they would have more. If you live in PA they come next day! Also, I believe you can also order them from babbittsonline.com.

I had to replace one of my exhaust valves. I picked the valves up from a cycle salvage place for pretty cheap, but I had to get both exhausts valves. The two I got were both better than the ones I had so now I am replacing them both.

I read somewhere that when you replace the valves, you also have to replace the the valve guides so I am also in the process of replacing those for the exhausts. This has become more of a pain than it needed to be, but hey at least I'm learning. The valve guides I got from bore-tech.com. They are bronze though, so you kind of have to be gentle when installing them.

I think thats it.... Could have been worse!
 

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yeah, that's not too shabby! did you get just the inner springs replaced? or did you do the outer springs as well?

i might just go for the works and get stainless valves, bronze valve guides, bore-techs KA tensioner, HD cam chain. I don't plan on getting into this engine again and want it to run strong.
 

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Discussion Starter · #18 ·
I actually didnt have to replace the outer springs. Surprisingly, they were all within the standard measurements that the manual gave. The exhausts were worn slightly more than the intakes, but still had good measurements.

Yeah, the stuff bore-tech has is really awesome and most of it is meant for racing. I am probably going to do the same this winter. I havent ridden this bike yet and am eager to do so. I figure I would ride it around this summer, figure out what it is lacking and where it tends to fail and then go crazy replacing things this winter.

I dont know if you would still be interested but I just found out they sell new camshafts and rockers. I forget if they are stock or aftermarket. They have a ton of stuff they sell but dont advertise on their website. Definitely call them up and ask. I actually got a set of used springs there, thinking that they were new which I was able to return.

I have also been eyeing the electronic ignition they have.... there's so many options!
 

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thanks for the heads up on the camshafts.

apparently their ignitions are for racing only. i think your lights will pull too much power with the EI. Have you check out Hondaman ignitions? Not quite electronic, but your points will last a lot longer and need to be serviced less often. Do some searching around for info.
 

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Hey dan and kitty, this may be of interest to you...
I spoke to a local mechanic who only does vintage stuff and does a ton of 350s (liberty vintage in philadelphia).
I showed him my camshaft and he said he wouldn't hesitate to use a cam in that shape in a customers engine, that the pitting wasn't that bad and I shouldn't worry about it. His exact words were, "Dude, I think you're being a little anal..."
So if it's helpful at all as a reference, pictures of my cam are here viewtopic.php?f=5&t=3390&start=0&st=0&sk=t&sd=a
 
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