1971 CB350 . . . 40 year hibernation

I added the CB350 to my insurance policy this morning and took it for a state inspection, which it passed. I'm always a little nervous riding a recently reanimated motorcycle in traffic, but the bike did well on the 5-6 mile trip (both ways). The front forks and wheel come from a CL360 and the 19" front wheel feels a little clumsy to me so far. The front suspension also felt a little bouncy, so maybe I should add a bit more fork oil or use something heavier. I hope the wheel was balanced correctly. I could smell that something was hot and I expect/hope that was coming from the scrambler exhaust, which has not seen much heat since it was originally painted last summer and then touched up with high-temp engine paint a few weeks back. When I shut the bike off, I noticed that there was visible smoke/steam/whatever coming from the breather outlet (no tube is attached currently).

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Hopefully next Thursday I can take care of registration and get a plate on this thing.
 
Way to go, on the road, and the bike looks great! There is always some smell from a rebuilt engine just cleaning solvents and small amounts of oil on parts no matter how much you clean and a small amount of vapor coming from the blow-by tube is normal but as you know get a downdraft hose on it soon to avoid a mess. If you need an OEM hose clip let me know as I have an extra.
 
Hopefully the smell was just fresh paint on the exhaust.
stl360+450 said:
When I shut the bike off, I noticed that there was visible smoke/steam/whatever coming from the breather outlet (no tube is attached currently).
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You should get the breather tube on it soon before oil mist makes a mess of the area on a longer ride.
 
LongDistanceRider said:
Check that the tires are fully seated all the way around on both sides, there's a small raised line right next to the rim that should be even for the entire circumference.
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Thanks, Jim, I will have a look and I appreciate the suggestion.

I assume this is a response to my comment about the front suspension feeling a little bouncy rather than you noticing something amiss in one of the recently posted photos?
 
Get the front wheel off the ground and spin it with a wire wheel in a drill held against the tire. Easy to see hopping from a poorly seated tire and check the speedo function too.
 
stl360+450 said:
Thanks, Jim, I will have a look and I appreciate the suggestion.

I assume this is a response to my comment about the front suspension feeling a little bouncy rather than you noticing something amiss in one of the recently posted photos?
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Just the bouncy comment, a rear tire can cause the front to bounce so check both.
 
LongDistanceRider said:
Check that the tires are fully seated all the way around on both sides, there's a small raised line right next to the rim that should be even for the entire circumference.
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I looked at both wheels today. The raised line seems to keep a pretty uniform distance from the rim on the front. On the rear it's close, although it gets closer to the rim for a short section. I grabbed a video for the rear and the questionable spot is in the 10-11 second range.


If this far enough off for concern?
 
stl360+450 said:
Might it help to release some of the tube pressure and then pump back up?
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It will also need a little talcum powder or other lube in that area to allow it to open up fully to seat correctly, it's dragging on the inner side of the rim in that area and not expanding fully. You'll want to deflate it fully, squeeze the sidewall inward away from the rim and dust some powder in the area, then overinflate it when you reinflate. You can take it up to 50 to 60 lbs briefly to help seat the tire.
 
ancientdad said:
It will also need a little talcum powder or other lube in that area to allow it to open up fully to seat correctly, it's dragging on the inner side of the rim in that area and not expanding fully. You'll want to deflate it fully, squeeze the sidewall inward away from the rim and dust some powder in the area, then overinflate it when you reinflate. You can take it up to 50 to 60 lbs briefly to help seat the tire.
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Thanks, Tom!
 
I rode the bike to work for the first time today. The carbs could still use some fine tuning at idle, but otherwise it felt good.

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I knew my attempts to get the rear tire fully seated last weekend did not completely correct the issue and I felt it on the ride. Will need to work on that again. You can see some residue of the talcum powder on the rear tire – I thought I had cleaned all of that off!
 
I think the witness line on the rear tire has been working it's way to a more uniform position, but still isn't perfect. I've deflated and reinflated the tire several times and am riding it occasionally.

I chose to test the carb kit brass with this build and held the original brass in reserve. So far, no issues and the bike feels good, although I'm still adjusting to the 19" front wheel. I can appreciate why some prefer the 350 to the 360, but I'm still partial to my 360G.

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stl360+450 said:
I think the witness line on the rear tire has been working it's way to a more uniform position, but still isn't perfect. I've deflated and reinflated the tire several times and am riding it occasionally.

I chose to test the carb kit brass with this build and held the original brass in reserve. So far, no issues and the bike feels good, although I'm still adjusting to the 19" front wheel. I can appreciate why some prefer the 350 to the 360, but I'm still partial to my 360G.
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How high a pressure have you inflated it to in order to fully seat the tire? I know it can be a bit scary but you can put 60 lbs in them if necessary.
 
ancientdad said:
How high a pressure have you inflated it to in order to fully seat the tire? I know it can be a bit scary but you can put 60 lbs in them if necessary.
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Probably about 40-45 psi and I'm using a hand pump. I've read that it helps to remove the valve and use an air compressor — I could try that if it doesn't get better.

I did pop a bicycle tube once that was pinched during the installation. That was very loud, so I'm probably a little gunshy from that experience.
 
stl360+450 said:
Probably about 40-45 psi and I'm using a hand pump. I've read that it helps to remove the valve and use an air compressor — I could try that if it doesn't get better.

I did pop a bicycle tube once that was pinched during the installation. That was very loud, so I'm probably a little gunshy from that experience.
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Yeah, a hand pump doesn't have the "impact" that a fast fill with an air compressor does with the valve removed, that would probably finish it off.
 
ancientdad said:
Yeah, a hand pump doesn't have the "impact" that a fast fill with an air compressor does with the valve removed, that would probably finish it off.
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Always raise the tire off the ground for first fill or if very low. If still not seating, let all air out and massage all around squeezing tire beads together towards center and loose from the rim edge. Then fill only about 10psi and spin to check seating before full fill.
 
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