Help! I need to replace my CB350 piston rings.

D

Dr.Chris

Kelevra chillin' in the sidecar of my 73 CB350G
Cyclewerx did a leakdown test on my right cylinder that had no compression. They`re reasonably confident it needs new piston rings. It`s high season so they don`t have time to pull the engine and heads but they`ll do the valves once the engine is out. I planto do the rings on both sides while the top is off, and probaby the cam chain. What I`m wondering is:

1) Anyone have a good DIY guide for these?
2) Other than the rings and the cam chain what else should I replace while I am in there?
3) Apart from the rings, a new cam chain, and a new gasket, what parts will I need?
4) What else am I missing?

Christopher
 
Ideally, you will want to measure your pistons/cylinders to confirm they're still in spec with regards to each other. If they are, then new rings will suffice with a hone of the cylinders ($20 per hole for honing usually).

You should consider cam chain tensioner/guides - not sure what's in the engine. You'll want a base gasket too, and there may be o-rings around the base of each cylinder.

Definitely seek out the service and parts manuals for your bike. That's your best DIY guide. It's dead easy to do all the work you're needing. I did my CB550F no problem.
 
Not to discourage you but rebuilding the top end is a big job. You'll also need a shitload of tools to do it properly. Torque wrench, feeler gauge, timing light, gasket sealer, etc. And you need to pull out the motor to do it. But if you can learn from reading a manual then go for it.
 
DrJ said:
Not to discourage you but rebuilding the top end is a big job. You'll also need a shitload of tools to do it properly. Torque wrench, feeler gauge, timing light, gasket sealer, etc. And you need to pull out the motor to do it. But if you can learn from reading a manual then go for it.
Click to expand...
Do you have a recomendation on WHICH shop manual I should buy?

Thanks,
Christopher
 
Hi I have done this rebuild a few times, its not that bad.
Download the cb350 pdf from repairclub.com
I bought the pistons off of ebay, brought i set to a locall machine shop out here, they did the oversize for my own.
I needed a gasket set- for the top end , a cam chain, and piston-piston ring set. Also lots of clean rags , oil and spray cans of brake cleaner.
The hardest part is getting a few hours in a row to work on it.
you could rebuild with out removing the motor, that's if you don't have any other problems ( low mile motor) I am doing my cam right now with only teh tank off.

Just email as you go, if I am on here I will reply.

Harry
 
Are you sure you can remove the top end of a CB350 twin top end without taking the motor out? Is there enough room between the engine studs and frame top tube to remove the head and barrel?
 
sorry www.repairmanualclub.com

you'll need to sign up,

serach for teh cb250 350 shop manual.

did you need a step by step list how to remove and replace the pistons?
 
hamfast said:
sorry www.repairmanualclub.com

you'll need to sign up,

serach for teh cb250 350 shop manual.

did you need a step by step list how to remove and replace the pistons?
Click to expand...
Unfortunately the CB350 manual for the twin keeps failing when I try to download it. I have the tank off and all the bolts are undone from the head, but it won't clear all the studs at once, it keeps bumping the top of the frame. I'm considering cutting a tiny notch so it will clear.

Christopher

P.S. Step by step would be great...
 
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