1974 CB360 - first bike/build

huck_finn

Been Around the Block
Here a couple of shots I took of the cylinders. None of the scoring could be felt when I ran my finger nail down the cylinder wall.
 

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irk miller

You've been mostly-dead all day.
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When you noticed the tensioner loose, did you check to make sure it was set to be tensioned? Did you notice if the bottom of the tensioner is seated? Check the piston skirts too. See if they have any marks.
 

huck_finn

Been Around the Block
When you noticed the tensioner loose, did you check to make sure it was set to be tensioned? Did you notice if the bottom of the tensioner is seated? Check the piston skirts too. See if they have any marks.
I found the tensioner update supplement over on Honda Twins. I must have never seated the tensioner slipper properly, because it was definitely too high and was likely caught behind the lower damper.

I didn't see anything on the piston skirts that wasn't already there when I installed them. And I didn't see anything that would make me think the valves were coming into contact with the crown.

I am going to reassemble tonight and make sure I have the tensioner slipper properly seated before trying to start it up again. Hopefully that will take care of it.
 

irk miller

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Good chance you were hearing noise related to the tensioner, but by asking about your piston skirts I was referring to piston slap. Your valves would come in contact with the crown.
 

huck_finn

Been Around the Block
Here are a few shots I took of my pistons last night
 

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huck_finn

Been Around the Block
Got back in the garage this past weekend and set the tensioner in place. Got everything back together, and still got a very similar noise. There is a little whine in the video, but I think it just might be the intake boot gasket not being set quite right. Any ideas on what I am hearing?

 

MiniatureNinja

Coast to Coast
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When you updated the tensioner - did you also get the new style top tensioner retainer? the original type is not compatible with the new tensioners.



old style on top, new on bottom
 

Jimbonaut

Over 1,000 Posts
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I haven't read through the thread so discount this if irrelevant, but that noise sounds very similar to the noise I heard in my engine after an overbore and rebuild. Turns out I'd installed the wrong head gasket - I installed the OEM diameter gasket rather than the overbore-specific gasket. The noise was the pistons coming into contact with the inner metal rings of the too-small gasket.
 

huck_finn

Been Around the Block
The tensioner retainer on my bike looks like the first (top) one in your photo. It has a thin side and a thick side - I installed with the thin side towards the center of the engine. Is that the updated version?

Head gasket is new: 69mm x 0.042'
 

ridesolo

“Kto ne riskuet, ne pyot champanskoye.”
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I haven't read through the thread so discount this if irrelevant, but that noise sounds very similar to the noise I heard in my engine after an overbore and rebuild. Turns out I'd installed the wrong head gasket - I installed the OEM diameter gasket rather than the overbore-specific gasket. The noise was the pistons coming into contact with the inner metal rings of the too-small gasket.

For what it's worth; when @Hurco550 and I installed the pistons and bored cylinders on my engine we were about to button it up and discovered that my copper gasket needed just a bit of "adjustment." Things looked pretty good and lined up, but the bore cutouts were a tad small. Levi cleared things up w/ a Dremel. You've had yours apart and now back together so I think you'd notice a bit of "mangled" gasket, but I thought I'd mention it anyway.
 

huck_finn

Been Around the Block
I am open to all suggestions. I didn't notice anything with the head gasket when I was reassembling. But it is worth taking another look at it.
 

MiniatureNinja

Coast to Coast
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The tensioner retainer on my bike looks like the first (top) one in your photo. It has a thin side and a thick side - I installed with the thin side towards the center of the engine. Is that the updated version?

Head gasket is new: 69mm x 0.042'

you need the one pictured on the bottom.

no one mentions this when talking about the updated tensioner I had to find this out myself while in the shop putting the engine together which was very frustrating to know I had to wait an addition week to put it together for one tiny little part) (see my experience with that https://www.dotheton.com/index.php?threads/75-cb360-bad-omen-yatagarasu-build.75072/post-901427
the new tensioner is angled (it slopes at the back so the tensioner is held in securely with the new position

you can find those holders on ebay all day long. but yes.. you need the updated tensioner holder

edit: the little black rubber insert is not shown in the bottom one, but they both need it
 
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irk miller

You've been mostly-dead all day.
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Sounds like rocker arm to me, as though one is adjusted to the high side of the lobe instead of the lowest side.
 

MiniatureNinja

Coast to Coast
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that doesn't sound like a tensioner issue, (but I would still correct it)
that sounds like a clearance issue.
 

huck_finn

Been Around the Block
For what it's worth; when @Hurco550 and I installed the pistons and bored cylinders on my engine we were about to button it up and discovered that my copper gasket needed just a bit of "adjustment." Things looked pretty good and lined up, but the bore cutouts were a tad small. Levi cleared things up w/ a Dremel. You've had yours apart and now back together so I think you'd notice a bit of "mangled" gasket, but I thought I'd mention it anyway.

It was the copper gasket causing the noise! I was able to find a NOS tensionor retainer on ebay and used a time-sert kit to repair a stripped bolt holding it down. I buttoned everything up, set the valves, did a rough timing and it started up on the first kick.

Then...

I went to do some fine tuning on the timing after it had warmed up a bit, and my kick start wouldn't engage (no electric start). I tried adjusting the clutch, even pulled the right cover off to double check the clutch basket - made sure the bolts were set to the proper torque. I am using some heavy duty clutch springs from Bore Tech.

When I pull in the clutch I can see that the plates move out to disengage, but it takes a few rocks to get the bike to move when it is disengaged. It is not the normal drag you feel when you pull in the clutch - it takes some intentional effort.

I deglazed the steel plates with some sand paper, and the friction plates have been soaking in oil throughout my rebuild. I don't have a problem finding neutral with the gear selector, and the bike rolls as it should when in neutral.
 

huck_finn

Been Around the Block
Pulled the engine and split the cases over the weekend - incredibly lucky that I didn't put it in gear while running. The clip on the internal end of the kickstart spindle had come off. It was so fatigued that I could put it on and flick it off by hand. I have a new one ordered and on the way. Hopefully it will be here this weekend.
 

crazypj

Split personality, I fake being smart
I am open to all suggestions. I didn't notice anything with the head gasket when I was reassembling. But it is worth taking another look at it.
If you have the 'straight' top holder it's the early style and should be changed. The 'cup' part will have the 'thin' side towards centre of engine
 

huck_finn

Been Around the Block
Got everything back together. I am getting 208 psi in my left cylinder and 210 psi in my right. I have taken it on some short rides and everything is sounding and feeling great (a little sluggish around 6K rpm though). I didn't re-jet the carbs yet - I wanted to get it moving again. Been over a year since I had it on the road.

I going to trim about 2 inches off the length of my seat too. It will line the back of the seat up with the rear axle. Right now it is sitting flush with the backside of the rear hub. Once I do that, I will finally get around to painting it.
 

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