Ccm: Seizure in Seattle

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pinsx3
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Ccm: Seizure in Seattle

Post by pinsx3 »

This is the barn find number one in the project bike section.

Fresh oil
Clean screens
New air filter
New oil lines
100 octane fuel With lead
History of running well and racing
Several fifteen minute practice sessions before race
Fifteen minutes of race practice
One full moto with big fourth gear pulls
Second moto made it three laps before it seized in a slow corner on top of the hill
Broke lt loose when coasting down To the pits

Low compression now. Kinda scrapy sounding I did not try to start
Oil looks dirty but no metal in screens in frame or sump.

Before it is pulled it apart, what do you all think are the suspected causes?

peter in Seattle.
Norman_John
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Re: Ccm: Seizure in Seattle

Post by Norman_John »

Heat - wild guesses are a combination of insufficient oil under the piston to cool it, timing too advanced at WOT followed by carb too weak on the over-run? Guessing the piston has picked up and nipped a ring.

However, you may be lucky and just have an exhaust valve tightened up!

Hope the post mortem is quick and easy.

John
pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

Good thoughts Norman! I'll let you know what I find out. Pete
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Re: Ccm: Seizure in Seattle

Post by Canberra »

Don't you love these posts where we all decide what has gone wrong before we strip the engines. We really should be considering gift to the winning guesses?

The B50 colours the oil after a short period of time so oil colour really doesn't give too much of a clue. Did you have sufficient/correct ring gaps on build?

John
pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

got hot! I wonder how and why? I mean it was kinda hot. Not really. 80 F.

89.5 piston approx
89.7-8 bore approx

Its supposed to be 90 by 90.

Here is a picture:
Attachments
aluminum transfer to the cylinder wall and some scoring.  exhaust side.
aluminum transfer to the cylinder wall and some scoring. exhaust side.
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Re: Ccm: Seizure in Seattle

Post by Canberra »

Pete,

That bore sounds rather worn? What type of piston is it? Is it hepolite? Where did you measure the piston - it is usually 1/2in up from base of the skirt running for/aft of the motor which should be the max dia.
Also where did you measure the bore - it should be 1/2 to inch below the top of the bore to give the most worn spot, again for/aft of the motor.

The type of piston should give us some idea of what clearance should be.

John
pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

Do you think clearance was the culprit?
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

I think it is a "four corner seizure" although there are only three areas of marks around the piston.
sclark309d
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Re: Ccm: Seizure in Seattle

Post by sclark309d »

Canberra wrote:Pete,

That bore sounds rather worn? What type of piston is it? Is it hepolite? Where did you measure the piston - it is usually 1/2in up from base of the skirt running for/aft of the motor which should be the max dia.
Also where did you measure the bore - it should be 1/2 to inch below the top of the bore to give the most worn spot, again for/aft of the motor.

The type of piston should give us some idea of what clearance should be.

John
I'm new to the BSA/CCM arena, and am looking to learn.
How can you tell what kind of piston it is or whether it's heplolite?

Steve
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Re: Ccm: Seizure in Seattle

Post by minetymenace »

Maybe if someone has a collection of piston photos, they could publish them in the Tech Write Ups section, otherwise, the best way is to post a few pictures and appeal to the members, to me they are a bit like sheep (pistons and members :???: ), how do you know if you have got hold of an ugly one?
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pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

I think it was lubrication because the small end bushing got hot and was loose enough to push out by hand. The piston pin had started to seize too. We are going to check all the passageways.

We were hoping that we could save the bore because apparently those sleeves are hard to come by. The bore had different measurements all over up down and around. And it looked like it had had some water in it at some time. The rings were a bit rusty and the bore had what looked like old rust stains or minor pitting.

but for certain, I need to bore it out. It was standard.

Does anyone know where I can get a 90 mm piston .20 over?

Pete
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steve m
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Re: Ccm: Seizure in Seattle

Post by steve m »

Ed Valiket at E&V Engineering
http://www.shopevengineering.com/EV-B50 ... 2087&fpg=1
and i'm sure Mark Cook at CCM-Britain would also be able to help.
both are frequent posters here so you could PM them. Marks web site is one of the red buttons at the top of every page here.

steve
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Mark Cook
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Re: Ccm: Seizure in Seattle

Post by Mark Cook »

Two things.

It looks like it ran dry. I wonder if the crank is blocked.

The second one ends up being the first. If you get an old CCM running well, it will clean the frame with hot oil and the debris shifted will block the crank.
This can happen in less than an hour.
Motorcycles and other parts manufactured by PES

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pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

Mark,

What would you recommend for a piston? It looks like I can go .20 over and keep the liner.

Pete
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

Thanks!!! I got a piston from Ed. Much appreciated on all the help.
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Re: Ccm: Seizure in Seattle

Post by Norman_John »

Make sure you wait till you actually get the piston and then fit the bore to match the piston. JE pistons run with much smaller clearances than BSA originals as they don't expand as much.

Good luck with removing the sludge trap...

Cheers
John
pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

Yeah. How do I go about that? Lol. Should I clean out the frame somehow?
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Re: Ccm: Seizure in Seattle

Post by minetymenace »

do you mean "how do I remove the sludge trap?"....There are quite a few posts on this topic, try searching for "Sludge Trap", this is quite a good one.
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pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

And Mark Cook wins the prize for long distance diagnosis!

Done with discovery- Lot's of carnage!
Crank pin oil galley plugged with sludge-put air pressure to it-No joy-

Odd thing was the sludge trap wasn't packed full, I think there was sludge from sum where that got ingested and wouldn't pass the galley into the crank pin.

Rod got hot, small end bush spun and loose.
needs new Crank pin,
new Cam shaft? Is this a CCM grind or standard b50?
Need to remachine t/c case for an oversize cam bushing -spun in case,

Luckily the mains-Oil pump and trans ok!

Primary Cush drive need's attention-

The head looks old, so that will have to be redone too.

so should I get a carillo rod or is the BSA good enough for mx work.
pinsx3
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Re: Ccm: Seizure in Seattle

Post by pinsx3 »

here are some photos of the carnage: :cry: :cry:

It's coming apart, so the question becomes. what should I do?

does a CCM use a standard cam?
should I upgrade to a Carillo rod?

Pete
Attachments
Big end CCM
Big end CCM
cam damage -- should I replace it?
cam damage -- should I replace it?
crank galley plugged.  Air wont clear.
crank galley plugged. Air wont clear.
Barry Creary
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Re: Ccm: Seizure in Seattle

Post by Barry Creary »

Pete
I replaced with Carrillo rod and JE piston and big end from Edv in USA, I also replaced the cam with a MX joycam from Mark Cook at PES in UK and got the crank balanced.hope this helps.
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Re: Ccm: Seizure in Seattle

Post by beat »

hi pins,
pinsx3 wrote:what do you all think are the suspected causes?
answer you giving yourself I guess :
pinsx3 wrote:Fresh oil
minetymenace wrote:Maybe if someone has a collection of piston photos, they could publish them
there are collections of sized B50 pistones in this forum !!!!

some examples from my very secret personaly collection :oops: :oops: :
DSCN8028.jpg
DSCN8029.jpg
anyone needs some more ???
beat :???:
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