[Crashoverride]

Decided to pull the top end off my second spare CB350 engine. It cleaned up good and turns over but I have no idea how many miles on it. Figured I would put it in projects because its the first time for me and I will take lots of pics and prob have lots of questions. First thing is to setup a workspace so I can store the parts safely and out of the way.

 

[ctrider]

Dang, it looks in better shape than my good engine on my bike, lol

 

[Crashoverride]

Well it seems to me to be in good shape. I think it has just sat on some shelf for many a year. I would like to learn and investigate the engine, make sure that if I do need to swap it in, I am putting something good. So here we go. Took off the top cover, came off nice and seems pretty clean. Took off the points plate and have the screws holding the left and right shaft housing in some penetrant for today. The screws looks to have never seen a screwdriver look new. I do have the manual and have watched the videos but will still like to ask some questions from our experts.
First one, when removing the camshaft nuts, should the engine be at any specific orientation?
Second should I remove the camshaft tensioner before I remove the left and right holders?

 

[Crashoverride]

Question. Once you take out the center nut, does the advancer just pull straight off the shaft?

 

[Crashoverride]

Ok I turned the barrel counter clock and it came off then the entire unit slid off. The barrel had a line pointing down and the unit has 286 in top left and a slot in the back that points NW when installed. Camshaft has mark /pin at the top also

 

[Crashoverride]

Ready to take the camshaft out tomorrow. The picture with the camchain wheel and the L and flat line. Is that how it should be lined up when it goes back together? If so should I mark the chain to either side with a marker or paint or such?

 

[LiamG6]

The procedure for engine disassembly/assembly are in the factory service manual, I would follow that and if you need clarification ask here. The FSM is very good and it is very helpful to have a good understanding of it. You can find an FSM for your bike on common motor co website. The FSM will explain the procedure better than most of us can but can get confusing at times because it assumes we know certain things or leaves things out. The reason I suggest following the FSM is it also tells you the tolerances for many parts so you can check them as you go along and decide if you need replacements or not.

 

[Crashoverride]

Got down to the bottom end. How much tightness do I have to keep on the chain when removing the bottom part? The cams looks to be nice condition.

 

[Crashoverride]

Any tips to remove the last part? The pistons move freely but I can't seem to remove the assembly. Seems to be stuck on.

 

[doode]

You cam chain might be bunched up in the bottom end. Straighten it and rock the crank back and forth

 

[Crashoverride]

Chain seems fine, moves easily when i give it a little tension and rotate the engine but it refuses to budge.

 

[Crashoverride]

The base gasket was just on there like glue. I eventually managed to break the seal by lifting and then is smoothly came off.

The rollers seem to be solid and in good shape and then guide is smooth.

Other than cleaning everything up first, what should be my next steps?

 

[Crashoverride]

Just to be clear, I was interested in replacing the gaskets cause I could see some weep from in the past and check the rest of it, not build a race engine or such. The cam/rockers and rollers look good. Is it good practice to install new rings in the pistons?

 

[Crashoverride]

While I figure out a plan everything gets its own box for safe keeping. They are all on sale at can tire.

 

[Yendor]

As far as the Cam Chain Roller go - it's not what they look like.

The problem is the rubber gets hard and cracks.

Unless they are known to be new replace them.
They are one part you don't want to have to go back in next year if that's when they decide to fall apart.
Think Rubber Bands - One day they are just fine and a week later they dry out crack and break.

 

[Boomer343]

What Yendor said ... when you get the new ones you will able to compare and see what they are supposed to feel like. Same with the cam chain. It is stretched after all the years of being under tension. Replace.

If the pistons and bores are reasonable then I buy a set of one oversize piston rings then file the ring end gap to spec. New ones also have the 3 piece oil control ring.

One of the followers has some pitting, clean and check the cam. You can use a flat diamond file to clean up minor imperfections on the cam and followers.

 

[Crashoverride]

Do I need to open up the bottom end to replace the chain and rollers?

 

[Boomer343]

To replace the chain you need to split the cases. Makes it easier to replace the case seals and to clean up/inspect bottom end. Easiest part of the whole process.

Not required to split cases to replace rollers.

 

[outobie]

Cam chains don’t normally need to be replaced. If the horizontal line on the left of the cam sprocket lines up with the top of the cam box whe the crank is at LT then your chain is fine. If the horizontal line does not line up at LT (when the head is fully assembled and torqued) then replace

definitely replace the cam chain rollers though.

Using oversized rings is a solution of last resort; to be done only when you can’t find the correct sized rings. If correct sized rings for Your bore don’t fit then you need to overbore the cylinders and go up a size in pistons as well as rings.

while you motor is apart is a good time to inspect your valves, valve guides, springs and seats

never file your cam or rockers with anything. They have a stellite surface hardening applied and filing will remove the hardening and dramatically shorten the life of the component. If the surface needs attention have it replaced or rehardened by Delta or megacycle cams

 

[Yendor]

Splitting the cases is MUCH Easier than the rest of the rebuild.
It also allows you to get in and clean out the sump which WILL be full of sludge and crud.

There is really no reason to take apart the transmission gears.
The both Shafts with gears in place can be removed and set aside intact.

There are a couple of things to watch out for but nothing difficult.

One of the biggest things to watch are the Alignment Pins on the Transmission Shaft End Cap Bearings.
The Bearing Caps have small Dimples and the Pins MUST be aligned to seat in the dimples.
If the cases are assembled and the pins are NOT in the dimples the Pins WILL break out a chip in the case.
This will allow the Bearing End Caps / Transmission Shaft to SLIP out of position and create shifting problems.