CB350 Top End Rebuild Questions

captainjmash

captainjmash

Working on first build - '73 CB350
Hey Guys,


I'm rebuilding a '73 CB350, but the motor is a type 1 from a '68 CL350.
The bike ran poorly when I bought it, but it did run. After Purchase I immediately started taking it apart
and replacing all worn and rusted parts.


- rebuilt the carbs, replaced all cable and lines, new rectifier, new coils wire and plugs, etc etc

This is my first project bike and I'm really excited about it. I'll post the details in the member
intro page section, but for now I would like some info from you pros out there.


I would like to get the head "rebuilt" ( hope I am using the term correctly. )


- Gaskets replaced
- Piston rings replaced
- Put back together with a new bolt set


If at all possible, I would like to leave the bottom end alone.


My question is, what will the estimated cost in labor be? I have a great idea about how much the parts will cost.


Also, if I undertake this, what else should I do? I.E. cam chain replacement?


Lastly, I'm in the Anaheim, CA area and any shop recommendations would be great.


Thanks for your time! Look forward to posting more as my bike progresses.


-Frank
 
Theres no way anyone can give you an accurate number on labor cost over the web. Your best bet is to call around or stop in at some local shops. Just a quick Google search turned up a ton of places, heres a few:

-Q&E Engine rebuilders, (714)630-7724
-Sonic Moto (714)533-9400
-Engines by AJ (714)609-1922
-Asylum Motorcycles (626)965-6600

Im not from the area, so I cant verify the quality of any of these shops by the way. I was just showing you how easy it is to find local mechanics. You should always stop by the shop and check it out personally before letting them work on your stuff. Talk to the techs, and see what other things theyre working on. The CB350 motor is about as simple as it gets, but I still wouldnt want just anyone messing with any of mine. The best thing you can do is find past customers, and see if they were happy with the place.

Ok, now that thats out of the way...

The work youre describing can easily be done at home. Though if you have never pulled the top end of a motor apart, it can seem quite daunting.

I would suggest finding a shop that will let you hang out and "help" them work on your motor. Its pretty rare to find guys willing to let that happen anymore, but its worth asking. Either that or ask around here on DTT. Im willing to bet that theres a member local to you that could possibly help you do the work yourself.

Either way, good luck! Keep us posted as to your progress, and oh ya...

REPLACE THE CAM CHAIN AND THE TENSIONER. The stock ones are crap. Youre looking at around $150 for a new unit. Les Barker as well as a few others make them.
 
VonYinzer, thanks for the great reply.

Will order the Cam chain and tensioner before I start working. I'm ready and willing to do the work myself, just need to find some guidance.
 
Well you'll have that to spare around here. I'm glad to see you tackle the work yourself. I'm currently working on my first rebuild as well and decided to do as much as I can without paying someone. I'm quite glad I've gone that route.
 
captainjmash said:
I'm ready and willing to do the work myself, just need to find some guidance.
Click to expand...

You have come to the right place sir.

The only thing you may need to pay for labor wise is to have the cylinders/pistons measured (to make sure they are still within spec) and have the cylinders honed (if necessary). I didn't know how to do it nor did I have the tools. I took my jugs and pistons into a shop that does lawnmowers and they did it for $25. *Normally I wouldn't go to a lawnmower shop, but the machinist there also restores Model A Fords.
 
Having the jugs honed is a must. While youre in there Id suggest some oversized pistons and a rebore as well...

http://cgi.ebay.com/ebaymotors/New-Set-Honda-CB350-CL350-SL350-Piston-Ring-Kit-1-00-_W0QQcmdZViewItemQQhashZitem53e5f20e7cQQitemZ360340131452QQptZMotorcyclesQ5fPartsQ5fAccessories

Also, one thing you could have a shop do (dont try this at home unless you KNOW what youre doing) is to have the head ported and polished. Really open some flow up. That Type 1 has the high rev cam, and with some engine work these motors can haul ass.
 
VonYinzer, if I were to go oversized would I maintain a clean power-band? I know I could benefit from more power but I do not want to sacrifice ride-ability or affect the power curve too much.


I was thinking about rings that are .25 over if I need to hone the cylinders.
What are your thoughts about a smaller step up?
 
if you're doing any of the work yourself, get a CLYMER manual for it.

have the cylinders honed first. the shop will be able to tell you if you're still within the range of stock pistons and rings, or if you will need an overbore, and they can do that too. then you'll need the correct sized pistons and rings. make sure you deburr the rings with some 400 grit sandpaper on the edges of the gap so it doesn't score the cylinder. make sure you inspect any bearing surfaces for scoring too, like the small ends of the connecting rods, wristpins, cam bearings, rocker arms and cam lobes. if in doubt, bring the part to a shop and they can tell you if it's useable. clean the head gasket surfaces well, and if possible, get a copper gasket, they work better. properly lap the valves, inspect the valve guides for wear, as shown in the clymer manual. ensure all oil passages are clear. you can do some small things to improve performance, like match porting the intakes to the carb boots, and the carburetor throats, removing the base gasket to up compression. you can probably get up to the claimed horsepower if you massage the engine a bit.
 
rockcitycafe, thanks for the great feedback.

I have a digital version of the manual, my buddy who has the same bike is assisting me with this. Although, he did not have to open up his motor for his rebuild.
 
Also, switching over to a set of Mikuni VM or similar carbs will really help with tuning and performance. A proper exhaust is also a plus.
 
Flugtechnik said:
Stop it Mike. You're going to send him down the path to financial ruin. ;)
Click to expand...

Very true!

This being my first build, I'm looking more for reliability than power. Just replacing the worn parts is really adding up. I have not even gotten to the fun "looks department" spending. I'm not going to fully cafe it out, just trimming off the fat and making her safe and reliable again. I plan to have this bike for a long time. My next build will be full cafe.

She's been sitting in my friends garage waiting to be put back together. The more I tore it apart the more work she needed. Big surprise right? All the parts needed to get her running again have finally come in and should have it back on the road this weekend!

Thanks everyone for the advice! I'll link my intro page here when I write it in the next few days.
 
There is a great deal on NOS piston's on Ebay right now. If I get stock pistons, can I put .25 over rings on them?
 
Usually, yes, just make sure the rings ware for stock pistons. You will have to have the cyinders bored .25 over.
 
captainjmash said:
rockcitycafe, thanks for the great feedback.

I have a digital version of the manual, my buddy who has the same bike is assisting me with this. Although, he did not have to open up his motor for his rebuild.
Click to expand...

digital version of the clymer manual? or the shop manual? get the clymer, my friend a bmw master technician, won't even crack open the motor on these old bikes until he has a clymer manual in his hands. the shop manual is good for some specs, like wear limits, etc, but the clymer people take the entire bike apart and reassemble it, so it's not a manual written by a tech writer at honda who never worked on the bike.
 
Rockcity, you're right. It's just a shop manual. Will pick up a Clymer soon. Thanks for the info!

As far as the engine goes, I just got a quote for honing @ $20 a cylinder.
Then I asked how much he would charge to replace the gaskets on the top end...... $400!

Does that sound like too much? I was thinking $300 tops. But, then again, I'm a total n00b at this.
 
Which gaskets? Just the head and breather? That will take you about two hours even if you have no clue what you're doing.

These bikes are pretty simple machines, man. If you have the tools (you should, all you need is a metric set of wrenches, a screwdriver, and some feeler gauges) and a brain, you can work on old Hondas.

If you get stuck, just take some photos and post on the forums. We love this stuff. :D
 
Sonreir said:
If you get stuck, just take some photos and post on the forums. We love this stuff. :D
Click to expand...

Thanks for the encouragement. Great idea about the pics, will post some tomorrow to get some recommendations.
 
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