CB350 to cafe' from scratch by a (not so much) teen

Alon said:
Thanks for your input! Why would I need a new gasket though? It’s brand new
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Because it's been compressed under the torque level of the head fasteners and will no longer crush, they only crush to fit once.
 
Alon said:
The motor only ran not more than 20 seconds a couple times. Would that be considered heat cycled?
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The head gasket still got crushed with cylinder head torque, meaning the crushable fire rings got crushed. You're welcome to re-use it, but you might regret it.
 
That would really depend on how it came off. Personally, since that’s an engine-out kind of thing, I’d take my lumps and use a fresh one. The downside being if it failed right away you’re pulling it again.
 
Do you guys know where I can get a 1.5 mm over-bore head gasket (I have 65.5 mm pistons). I saw on another thread here that the stock sized gasket would work up to a 1mm oversized piston.
The only thing close to relevant was a 68 mm gasket for sale on ebay, but I'm pretty sure that's too big - listing.
 
Alon said:
Do you guys know where I can get a 1.5 mm over-bore head gasket (I have 65.5 mm pistons). I saw on another thread here that the stock sized gasket would work up to a 1mm oversized piston.
The only thing close to relevant was a 68 mm gasket for sale on ebay, but I'm pretty sure that's too big - listing.
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Just found this Cometic 66 mm gasket - https://ebay.us/m/rvDeOL
 
I put back everything together and getting really close to get it licensed!
Two problems that I have are:
1. The rear brake pedal collar/bushing is stuck frozen inside the pedal which doesn’t allow it to be torqued and move freely.
2. Both tires touch the floor when on the center stand. It’s very hard getting it off and on it. When I put some plywood under for some height then the rear tire rises and it’s just above the floor.

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That centerstand doesn't look like it's fully deployed. Maybe something is blocking it?
 
Centerstand looks bent backwards a bit to me, previous owners probably slammed it back on the stand or did a lot of kick starting while it was on the centerstand. Or the cross-shaft get pivots on may well be bent. Of course, if the bike has larger tires on it than stock that also contributes.
 
I know the CL models have a stopper on them. Mine doesn’t as one off a CB and also the part where you push with your foot was broken off at one time. I’ll remove it and post some pics of it to show you guys better.
I can say that the left bracket on the frame is a little warped. Pretty sure on of the POs crashed it at one point. The brake pedal shows signs of a crash and also the problem the I had with the engine mount.
 
Alon said:
I know the CL models have a stopper on them. Mine doesn’t as one off a CB and also the part where you push with your foot was broken off at one time. I’ll remove it and post some pics of it to show you guys better.
I can say that the left bracket on the frame is a little warped. Pretty sure on of the POs crashed it at one point. The brake pedal shows signs of a crash and also the problem the I had with the engine mount.
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Yep, the stops or fame tube is smashed in. Probably easier to weld/modify the center stand at this point.
 
Image 5214.
Set a straight edge/ruler against the upper pipe section where it's braced, right side in photo. The end of the bracing is where I see the bend.
I don't see a bend in 5215 so I suspect it starts up near the pivot section.
 
I'll try straightening it with some kind of metal pipe
 
I’m tackling the seat hoop that the PO welded on. It was clearly gonna hit the wheel if the shocks compressed enough so I cut it off. I left only one shock on and compressed it all the way to see the clearance I would need. Should I actually anticipate the being able to go this high up? I feel like this would make it really problematic putting a cafe racer/brat style seat.
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Alon said:
I’m tackling the seat hoop that the PO welded on. It was clearly gonna hit the wheel if the shocks compressed enough so I cut it off. I left only one shock on and compressed it all the way to see the clearance I would need. Should I actually anticipate the being able to go this high up? I feel like this would make it really problematic putting a cafe racer/brat style seat.
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I wasn't going for a cafe style hoop at the back of my frame, just revised rear fender mounts for the aftermarket fender I chose. This is with both shocks off the swingarm to measure max travel for the 1.5" shorter shocks I bought to lower my bike that amount.

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I’m ready to get it licensed!!!
Any recommendations for breaking it in? What’s the process?
 
1st ride run up and down thru the gears using @5K as shift points. Decel is as important as accel. Run @ 5 miles
Let cool and retorque the head. Check valve clearances and timing, reset mixture as needed.
2nd ride repeat the 1st using 6K shift points, run @5 miles.
Keep repeating the rides progressively increasing shift point rpm.
After 100 miles or so change the oil and clean the filter including the pickup screen.
 
LongDistanceRider said:
1st ride run up and down thru the gears using @5K as shift points. Decel is as important as accel. Run @ 5 miles
Let cool and retorque the head. Check valve clearances and timing, reset mixture as needed.
2nd ride repeat the 1st using 6K shift points, run @5 miles.
Keep repeating the rides progressively increasing shift point rpm.
After 100 miles or so change the oil and clean the filter including the pickup screen.
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Awesome!! Just to clarify, what do you mean by run @ 5 miles?
 
I ran it for less than a mile and it’s leaking a lot of oil from the left side. I’m thinking from the points cover and from the starter 😦
 
Alon said:
I ran it for less than a mile and it’s leaking a lot of oil from the left side. I’m thinking from the points cover and from the starter 😦
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Possibly the left cam bearing cover gasket on backwards. If the oil is coming from the inside of the points cover it would likely be the seal on the camshaft behind the advancer.
 
I checked under the points cover and it doesn’t seem to be coming from the seal under it.
You can see a little bit of oil on the bottom ridge of the points cover. And a lot on the fins (marked in the image below).
I’m thinking it could maybe be coming from between the cylinder head and cylinders. The spark plug cap is pretty oily.

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But, the head gasket is where the blue arrow is pointing, and oil generally doesn't go up that far from a head gasket leak. I'd suspect the gasket behind the left cam bearing cover.

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I noticed a little bit of oil also around the gasket between the cam box and head. Could it be that the engine nuts weren’t torqued to the correct specifications? I think my larger torque wrench gave a false reading. I checked yesterday with my smaller one that goes up to 12.5 ft lbs and I had a little wiggle room. So let’s say it was torqued around 12 ft lbs. Also I’m using stainless steel bolts and nuts from alloyboltz.
 
Alon said:
I noticed a little bit of oil also around the gasket between the cam box and head. Could it be that the engine nuts weren’t torqued to the correct specifications? I think my larger torque wrench gave a false reading. I checked yesterday with my smaller one that goes up to 12.5 ft lbs and I had a little wiggle room. So let’s say it was torqued around 12 ft lbs. Also I’m using stainless steel bolts and nuts from alloyboltz.
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Unfortunately, retorquing the head and cylinder rarely stops an oil leak.
 
Good news! I think i found the leak. Its from the left cam box points side gasket.
Can i take this side off without taking the engine out?

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That was my suspicion from the start, and yes it CAN be done with the engine in the frame, but you have to be very careful to do it correctly or you can cause yourself a lot of trouble. You have to position the crankshaft as if you're going to adjust the cam chain (90° past LT on compression stroke) and loosen all the valve adjusters to maximum clearance to take the load off the camshaft so the left bearing cover will slide off and back on without force. And while the cam bearing cover is off you do NOT rotate the engine at all.
 
I took it off and I think I put it on reversed. Also you can see the gasket was pinched.
This is how I put it:
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I put another one I had on now:
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So that oil leak has been fixed. Turns out I have another one between the cambox and head 🤦🏻‍♂️.
Also, when setting the valve clearance, the right side exhaust has a very tight 0.004’’ clearance only this way (any other direction is even tighter). I set each side on the respective top dead center of compression stroke (LT and T)
Right side:
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Left side:
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Alon said:
So that oil leak has been fixed. Turns out I have another one between the cambox and head 🤦🏻‍♂️.
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Ugh, sorry to hear it. That would definitely require the engine to be removed from the frame.
Alon said:
Also, when setting the valve clearance, the right side exhaust has a very tight 0.004’’ clearance only this way (any other direction is even tighter).
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I'm afraid this tells me that when your valve seats were cut, the valve depth is now deeper in the head which takes up more of the distance between valve stem tip and the rocker arm. Problem is, on the 350 and DOHC 450 there's only so much adjustment movement available from the eccentric valve adjuster shaft to compensate for the reduced clearance, and the solution is to have that valve stem "tipped" a few thousandths to give more adjustment clearance.
 
ancientdad said:
Ugh, sorry to hear it. That would definitely require the engine to be removed from the frame.

I'm afraid this tells me that when your valve seats were cut, the valve depth is now deeper in the head which takes up more of the distance between valve stem tip and the rocker arm. Problem is, on the 350 and DOHC 450 there's only so much adjustment movement available from the eccentric valve adjuster shaft to compensate for the reduced clearance, and the solution is to have that valve stem "tipped" a few thousandths to give more adjustment clearance.
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Thanks for the help!! How do I know how much needs to be removed?
 
Alon said:
Thanks for the help!! How do I know how much needs to be removed?
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You don't really know exactly, but a machinist can take off as little as .001" to .002". If you can barely achieve a .004" adjustment right now and the valves will seat and drop into the head a tiny bit more as the miles on the rebuild add up, you'll want at least .002" to .004" more for future clearance needs. When you tell the machinist what is happening and what your valve adjustment clearances are supposed to be (.004" exhaust), he should have a good idea of how much to take off.
 
Before opening the engine again, do you think I'll need a new cylinder head gasket? Because I did run the engine. It's a 60$ gasket, and it takes a month just to get it here :(.
 
Alon said:
Before opening the engine again, do you think I'll need a new cylinder head gasket? Because I did run the engine. It's a 60$ gasket, and it takes a month just to get it here :(.
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The head gasket includes metal crush rings for the cylinders that are designed to be used only once. Once the head is torqued, those rings are crushed. It may be worth keeping a spare on hand to avoid delays.

Did you find the location of the second oil leak?
 
ancientdad said:
You don't really know exactly, but a machinist can take off as little as .001" to .002". If you can barely achieve a .004" adjustment right now and the valves will seat and drop into the head a tiny bit more as the miles on the rebuild add up, you'll want at least .002" to .004" more for future clearance needs. When you tell the machinist what is happening and what your valve adjustment clearances are supposed to be (.004" exhaust), he should have a good idea of how much to take off.
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Can I grind off the rocker arm instead?
Is that something I can do by myself?
 
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