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72 CB350
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Discussion Starter · #1 ·
The bike was exposed to the weather and I am unable to remove the cam off of the mechanical advance.
It has been soaking in PB blaster for 2 weeks. I've heating the cam and also put it in the deep freezer with no luck. Any suggestions?

Is that an oillite bushing the cam rotates on?

As always I appreciate the input!
 

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Ok, try this but you must obey all common sense safety first principles and rules....hot oil.

Get a small sauce pan and camping stove. Small Sauce pan with a lid.

Outside, in no rain or snow type weather, set up stove. Place sauce pan on stove. Thread copper wire thru advancer centre hole to make easy to use handle. Place advancer unit in sauce pan after having checked it for no hot oil damageable parts, drive side down. Pour in enough engine oil ( even used ) oil to cover most of the unit. Heat oil until just before it starts to show the hint of smoking. Remove saucepan from heat.

You may see oil rise between advancer base and moving cam, capiliiry action, along with rust...

Allow to cool down.

Does the cam now rotate, even slightly, on the base unit ?

If yes, patience patience patience.

If no, repeat hot oil.

Rotates this time ?

No.

Third try....

No joy...

Set up on firm bench, wood blocks either side of advancer base, cam downwards, with enough clearance, so that a "gravity hammer" can be used.

Place advancer in oil, cam end down, with sufficient oil to heat the cam. Heat oil.

Turn off heat, gloved hand, remove the advancer from the hot oil and place the advancer base only in cold water, to cool the base a bit, use gravity hammer/momentum to hopefully cause the cam to come off the shaft it turns on.

The cold water should be at least 10 foot away from the hot oil. DO NOT allow water or anything else anywhere near the hot oil.

You could of course, set up the advancer so in hot oil, the cam drops off the shaft due to gravity.

Naturally, no pets, kids or d#拢&@55es anywhere near that hot oil.

Before you do any of this, make your self fully aware of all the risks of using heat, hot oil etc. and only do this technique OUTSIDE !!!!

Research " chip pan fires", this is important.

I recon with a good initial heating the parts will turn at least.

Your picture shows no sign of "riveting".....

The hot oil technique works on all sorts of problems, I have to use it from time to time, this being one of them.

Stand by......

Dd23馃
 

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The end of the base plate post the cam rotates a bit on " domed or riveted" stopping the cam from lifting off...

You have access to a lathe or large chuck ?

A 2 inch strip of leather belt...
To grip and protect the cam .....

Take your time...the hot old method does work...just be really carefull.

Research chip pan fires....
 

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This type of heat gun might be simpler and it works for a variety of issues. A lazer pointer temp sensor is also handy because you need to get thins around 150F or hotter to make things move.

Careful use of adjustable pliers and some old inner tube protecting the cam usually works as well. Remember when you do get it apart you can reasemble it 180 degrees out. and it won't start.
 

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There is another thing to try, and that is KROIL. Special Stuff. Gets into place where there are no places. Upgrade over PB Blaster. It could also take some time, with multiple applications.
Buy, try: Kroil Original Penetrating Oil | Kano Laboratories, LLC
Otherwise, since you could be stuck with buying a new cam and advancer anyway, heat up the advancer with a torch, and try using a puller to try to pull it off. I like the HF heat guy, above, for the money. Or take it to an automotive machine shop and let them have a crack at it.
 

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Here's a tool I have used a lot. I even use it on exhaust pipes to see which cylinder is not running. When heating up cases to put in bearing and such it really lets you get things up to temp. It takes a long time to heat up a aluminum case.
 

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Any joy with the hot oil technique at all ?

Does the cam rotate, even a fraction, relative to be base plate ?

Cam looks a bit "blued" so you have heated it ?

Hope you removed the springs ?

Feedback to help others...
 

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72 CB350
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Discussion Starter · #13 ·
It looks like HF is the place to shop, got one of those too!
I have not has the chance to boil it, will do soon.
I heated it let it cool, put it in the deep freezer and the let it get to room temp and heated x 3
It has been soaking in PB and now trying Kroil before the boil.

THX guys
 

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Unless you are doing this as an exercise to take it apart quit now and get a serviceable part. It needs to have fairly tight specs or your timing will be off one side to the other and that rough surface the points run on will take the rub blocks out in no time.
 

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Can you post some more pictures from different positions, if the unit to include the small rounded "foot" of the weights were they fit into the slots in the cam part. The weights foot moves, advancing the cam.

Are those feet in place properly or are they jamming the cam ?

Pictures pictures pictures.....
 

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72 CB350
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Discussion Starter · #16 ·
Thanks dd23 for the tip

Oil temp 215 degrees 10 minutes and let cool. Minimal difficulty to remove the cam.

Double, double toil and trouble;
Fire burn and caldron bubble.
Cool it with a baboon's blood, (forewent the baboon's blood)
Then the cam is free and loose and good. 馃お馃馃槑

FREE AT LAST, FREE AT LAST, FREE AT LAST 馃檪馃檭馃檪馃檭馃檪馃檭

I want to thank everyone else who chimed in!!! This is a GREAT site!!!馃憡

Thank God it was not an exercise in futility.

Bicycle part Auto part Metal Circle Fashion accessory
 

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Yes, a risky process but it works, on many things.

Did you see the hot oil wick up and appear at the top ?

If the hot oil covered the top, did you see some rising rusty oil ?

It's free, wonderfully news. Just reassemble correctly else engine will not start.

Good show and happy to help, which is why I/we are here.

Dd23馃馃榿
 
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